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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/fork.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * 'fork.c' contains the help-routines for the 'fork' system call | |
9 | * (see also entry.S and others). | |
10 | * Fork is rather simple, once you get the hang of it, but the memory | |
11 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' | |
12 | */ | |
13 | ||
1da177e4 | 14 | #include <linux/slab.h> |
4eb5aaa3 | 15 | #include <linux/sched/autogroup.h> |
6e84f315 | 16 | #include <linux/sched/mm.h> |
f7ccbae4 | 17 | #include <linux/sched/coredump.h> |
8703e8a4 | 18 | #include <linux/sched/user.h> |
6a3827d7 | 19 | #include <linux/sched/numa_balancing.h> |
03441a34 | 20 | #include <linux/sched/stat.h> |
29930025 | 21 | #include <linux/sched/task.h> |
68db0cf1 | 22 | #include <linux/sched/task_stack.h> |
32ef5517 | 23 | #include <linux/sched/cputime.h> |
037741a6 | 24 | #include <linux/rtmutex.h> |
1da177e4 LT |
25 | #include <linux/init.h> |
26 | #include <linux/unistd.h> | |
1da177e4 LT |
27 | #include <linux/module.h> |
28 | #include <linux/vmalloc.h> | |
29 | #include <linux/completion.h> | |
1da177e4 LT |
30 | #include <linux/personality.h> |
31 | #include <linux/mempolicy.h> | |
32 | #include <linux/sem.h> | |
33 | #include <linux/file.h> | |
9f3acc31 | 34 | #include <linux/fdtable.h> |
da9cbc87 | 35 | #include <linux/iocontext.h> |
1da177e4 LT |
36 | #include <linux/key.h> |
37 | #include <linux/binfmts.h> | |
38 | #include <linux/mman.h> | |
cddb8a5c | 39 | #include <linux/mmu_notifier.h> |
133ff0ea | 40 | #include <linux/hmm.h> |
1da177e4 | 41 | #include <linux/fs.h> |
615d6e87 DB |
42 | #include <linux/mm.h> |
43 | #include <linux/vmacache.h> | |
ab516013 | 44 | #include <linux/nsproxy.h> |
c59ede7b | 45 | #include <linux/capability.h> |
1da177e4 | 46 | #include <linux/cpu.h> |
b4f48b63 | 47 | #include <linux/cgroup.h> |
1da177e4 | 48 | #include <linux/security.h> |
a1e78772 | 49 | #include <linux/hugetlb.h> |
e2cfabdf | 50 | #include <linux/seccomp.h> |
1da177e4 LT |
51 | #include <linux/swap.h> |
52 | #include <linux/syscalls.h> | |
53 | #include <linux/jiffies.h> | |
54 | #include <linux/futex.h> | |
8141c7f3 | 55 | #include <linux/compat.h> |
207205a2 | 56 | #include <linux/kthread.h> |
7c3ab738 | 57 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 58 | #include <linux/rcupdate.h> |
1da177e4 LT |
59 | #include <linux/ptrace.h> |
60 | #include <linux/mount.h> | |
61 | #include <linux/audit.h> | |
78fb7466 | 62 | #include <linux/memcontrol.h> |
f201ae23 | 63 | #include <linux/ftrace.h> |
5e2bf014 | 64 | #include <linux/proc_fs.h> |
1da177e4 LT |
65 | #include <linux/profile.h> |
66 | #include <linux/rmap.h> | |
f8af4da3 | 67 | #include <linux/ksm.h> |
1da177e4 | 68 | #include <linux/acct.h> |
893e26e6 | 69 | #include <linux/userfaultfd_k.h> |
8f0ab514 | 70 | #include <linux/tsacct_kern.h> |
9f46080c | 71 | #include <linux/cn_proc.h> |
ba96a0c8 | 72 | #include <linux/freezer.h> |
ca74e92b | 73 | #include <linux/delayacct.h> |
ad4ecbcb | 74 | #include <linux/taskstats_kern.h> |
0a425405 | 75 | #include <linux/random.h> |
522ed776 | 76 | #include <linux/tty.h> |
fd0928df | 77 | #include <linux/blkdev.h> |
5ad4e53b | 78 | #include <linux/fs_struct.h> |
7c9f8861 | 79 | #include <linux/magic.h> |
d70f2a14 | 80 | #include <linux/sched/mm.h> |
cdd6c482 | 81 | #include <linux/perf_event.h> |
42c4ab41 | 82 | #include <linux/posix-timers.h> |
8e7cac79 | 83 | #include <linux/user-return-notifier.h> |
3d5992d2 | 84 | #include <linux/oom.h> |
ba76149f | 85 | #include <linux/khugepaged.h> |
d80e731e | 86 | #include <linux/signalfd.h> |
0326f5a9 | 87 | #include <linux/uprobes.h> |
a27bb332 | 88 | #include <linux/aio.h> |
52f5684c | 89 | #include <linux/compiler.h> |
16db3d3f | 90 | #include <linux/sysctl.h> |
5c9a8750 | 91 | #include <linux/kcov.h> |
d83a7cb3 | 92 | #include <linux/livepatch.h> |
48ac3c18 | 93 | #include <linux/thread_info.h> |
afaef01c | 94 | #include <linux/stackleak.h> |
1da177e4 LT |
95 | |
96 | #include <asm/pgtable.h> | |
97 | #include <asm/pgalloc.h> | |
7c0f6ba6 | 98 | #include <linux/uaccess.h> |
1da177e4 LT |
99 | #include <asm/mmu_context.h> |
100 | #include <asm/cacheflush.h> | |
101 | #include <asm/tlbflush.h> | |
102 | ||
ad8d75ff SR |
103 | #include <trace/events/sched.h> |
104 | ||
43d2b113 KH |
105 | #define CREATE_TRACE_POINTS |
106 | #include <trace/events/task.h> | |
107 | ||
ac1b398d HS |
108 | /* |
109 | * Minimum number of threads to boot the kernel | |
110 | */ | |
111 | #define MIN_THREADS 20 | |
112 | ||
113 | /* | |
114 | * Maximum number of threads | |
115 | */ | |
116 | #define MAX_THREADS FUTEX_TID_MASK | |
117 | ||
1da177e4 LT |
118 | /* |
119 | * Protected counters by write_lock_irq(&tasklist_lock) | |
120 | */ | |
121 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
fb0a685c | 122 | int nr_threads; /* The idle threads do not count.. */ |
1da177e4 LT |
123 | |
124 | int max_threads; /* tunable limit on nr_threads */ | |
125 | ||
126 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
127 | ||
c59923a1 | 128 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
129 | |
130 | #ifdef CONFIG_PROVE_RCU | |
131 | int lockdep_tasklist_lock_is_held(void) | |
132 | { | |
133 | return lockdep_is_held(&tasklist_lock); | |
134 | } | |
135 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
136 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
137 | |
138 | int nr_processes(void) | |
139 | { | |
140 | int cpu; | |
141 | int total = 0; | |
142 | ||
1d510750 | 143 | for_each_possible_cpu(cpu) |
1da177e4 LT |
144 | total += per_cpu(process_counts, cpu); |
145 | ||
146 | return total; | |
147 | } | |
148 | ||
f19b9f74 AM |
149 | void __weak arch_release_task_struct(struct task_struct *tsk) |
150 | { | |
151 | } | |
152 | ||
f5e10287 | 153 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
e18b890b | 154 | static struct kmem_cache *task_struct_cachep; |
41101809 TG |
155 | |
156 | static inline struct task_struct *alloc_task_struct_node(int node) | |
157 | { | |
158 | return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node); | |
159 | } | |
160 | ||
41101809 TG |
161 | static inline void free_task_struct(struct task_struct *tsk) |
162 | { | |
41101809 TG |
163 | kmem_cache_free(task_struct_cachep, tsk); |
164 | } | |
1da177e4 LT |
165 | #endif |
166 | ||
b235beea | 167 | void __weak arch_release_thread_stack(unsigned long *stack) |
f19b9f74 AM |
168 | { |
169 | } | |
170 | ||
b235beea | 171 | #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR |
41101809 | 172 | |
0d15d74a TG |
173 | /* |
174 | * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a | |
175 | * kmemcache based allocator. | |
176 | */ | |
ba14a194 | 177 | # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) |
ac496bf4 AL |
178 | |
179 | #ifdef CONFIG_VMAP_STACK | |
180 | /* | |
181 | * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB | |
182 | * flush. Try to minimize the number of calls by caching stacks. | |
183 | */ | |
184 | #define NR_CACHED_STACKS 2 | |
185 | static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); | |
19659c59 HR |
186 | |
187 | static int free_vm_stack_cache(unsigned int cpu) | |
188 | { | |
189 | struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu); | |
190 | int i; | |
191 | ||
192 | for (i = 0; i < NR_CACHED_STACKS; i++) { | |
193 | struct vm_struct *vm_stack = cached_vm_stacks[i]; | |
194 | ||
195 | if (!vm_stack) | |
196 | continue; | |
197 | ||
198 | vfree(vm_stack->addr); | |
199 | cached_vm_stacks[i] = NULL; | |
200 | } | |
201 | ||
202 | return 0; | |
203 | } | |
ac496bf4 AL |
204 | #endif |
205 | ||
ba14a194 | 206 | static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) |
b69c49b7 | 207 | { |
ba14a194 | 208 | #ifdef CONFIG_VMAP_STACK |
ac496bf4 AL |
209 | void *stack; |
210 | int i; | |
211 | ||
ac496bf4 | 212 | for (i = 0; i < NR_CACHED_STACKS; i++) { |
112166f8 CL |
213 | struct vm_struct *s; |
214 | ||
215 | s = this_cpu_xchg(cached_stacks[i], NULL); | |
ac496bf4 AL |
216 | |
217 | if (!s) | |
218 | continue; | |
ac496bf4 | 219 | |
ca182551 KK |
220 | /* Clear stale pointers from reused stack. */ |
221 | memset(s->addr, 0, THREAD_SIZE); | |
e01e8063 | 222 | |
ac496bf4 | 223 | tsk->stack_vm_area = s; |
ac496bf4 AL |
224 | return s->addr; |
225 | } | |
ac496bf4 | 226 | |
9b6f7e16 RG |
227 | /* |
228 | * Allocated stacks are cached and later reused by new threads, | |
229 | * so memcg accounting is performed manually on assigning/releasing | |
230 | * stacks to tasks. Drop __GFP_ACCOUNT. | |
231 | */ | |
48ac3c18 | 232 | stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, |
ac496bf4 | 233 | VMALLOC_START, VMALLOC_END, |
9b6f7e16 | 234 | THREADINFO_GFP & ~__GFP_ACCOUNT, |
ac496bf4 AL |
235 | PAGE_KERNEL, |
236 | 0, node, __builtin_return_address(0)); | |
ba14a194 AL |
237 | |
238 | /* | |
239 | * We can't call find_vm_area() in interrupt context, and | |
240 | * free_thread_stack() can be called in interrupt context, | |
241 | * so cache the vm_struct. | |
242 | */ | |
243 | if (stack) | |
244 | tsk->stack_vm_area = find_vm_area(stack); | |
245 | return stack; | |
246 | #else | |
4949148a VD |
247 | struct page *page = alloc_pages_node(node, THREADINFO_GFP, |
248 | THREAD_SIZE_ORDER); | |
b6a84016 ED |
249 | |
250 | return page ? page_address(page) : NULL; | |
ba14a194 | 251 | #endif |
b69c49b7 FT |
252 | } |
253 | ||
ba14a194 | 254 | static inline void free_thread_stack(struct task_struct *tsk) |
b69c49b7 | 255 | { |
ac496bf4 | 256 | #ifdef CONFIG_VMAP_STACK |
9b6f7e16 RG |
257 | struct vm_struct *vm = task_stack_vm_area(tsk); |
258 | ||
259 | if (vm) { | |
ac496bf4 AL |
260 | int i; |
261 | ||
9b6f7e16 RG |
262 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { |
263 | mod_memcg_page_state(vm->pages[i], | |
264 | MEMCG_KERNEL_STACK_KB, | |
265 | -(int)(PAGE_SIZE / 1024)); | |
266 | ||
267 | memcg_kmem_uncharge(vm->pages[i], 0); | |
268 | } | |
269 | ||
ac496bf4 | 270 | for (i = 0; i < NR_CACHED_STACKS; i++) { |
112166f8 CL |
271 | if (this_cpu_cmpxchg(cached_stacks[i], |
272 | NULL, tsk->stack_vm_area) != NULL) | |
ac496bf4 AL |
273 | continue; |
274 | ||
ac496bf4 AL |
275 | return; |
276 | } | |
ac496bf4 | 277 | |
0f110a9b | 278 | vfree_atomic(tsk->stack); |
ac496bf4 AL |
279 | return; |
280 | } | |
281 | #endif | |
282 | ||
283 | __free_pages(virt_to_page(tsk->stack), THREAD_SIZE_ORDER); | |
b69c49b7 | 284 | } |
0d15d74a | 285 | # else |
b235beea | 286 | static struct kmem_cache *thread_stack_cache; |
0d15d74a | 287 | |
9521d399 | 288 | static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, |
0d15d74a TG |
289 | int node) |
290 | { | |
b235beea | 291 | return kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node); |
0d15d74a TG |
292 | } |
293 | ||
ba14a194 | 294 | static void free_thread_stack(struct task_struct *tsk) |
0d15d74a | 295 | { |
ba14a194 | 296 | kmem_cache_free(thread_stack_cache, tsk->stack); |
0d15d74a TG |
297 | } |
298 | ||
b235beea | 299 | void thread_stack_cache_init(void) |
0d15d74a | 300 | { |
f9d29946 DW |
301 | thread_stack_cache = kmem_cache_create_usercopy("thread_stack", |
302 | THREAD_SIZE, THREAD_SIZE, 0, 0, | |
303 | THREAD_SIZE, NULL); | |
b235beea | 304 | BUG_ON(thread_stack_cache == NULL); |
0d15d74a TG |
305 | } |
306 | # endif | |
b69c49b7 FT |
307 | #endif |
308 | ||
1da177e4 | 309 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 310 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
311 | |
312 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 313 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
314 | |
315 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 316 | struct kmem_cache *files_cachep; |
1da177e4 LT |
317 | |
318 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 319 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
320 | |
321 | /* SLAB cache for vm_area_struct structures */ | |
3928d4f5 | 322 | static struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
323 | |
324 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 325 | static struct kmem_cache *mm_cachep; |
1da177e4 | 326 | |
490fc053 | 327 | struct vm_area_struct *vm_area_alloc(struct mm_struct *mm) |
3928d4f5 | 328 | { |
a670468f | 329 | struct vm_area_struct *vma; |
490fc053 | 330 | |
a670468f | 331 | vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
027232da KS |
332 | if (vma) |
333 | vma_init(vma, mm); | |
490fc053 | 334 | return vma; |
3928d4f5 LT |
335 | } |
336 | ||
337 | struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) | |
338 | { | |
95faf699 LT |
339 | struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
340 | ||
341 | if (new) { | |
342 | *new = *orig; | |
343 | INIT_LIST_HEAD(&new->anon_vma_chain); | |
344 | } | |
345 | return new; | |
3928d4f5 LT |
346 | } |
347 | ||
348 | void vm_area_free(struct vm_area_struct *vma) | |
349 | { | |
350 | kmem_cache_free(vm_area_cachep, vma); | |
351 | } | |
352 | ||
ba14a194 | 353 | static void account_kernel_stack(struct task_struct *tsk, int account) |
c6a7f572 | 354 | { |
ba14a194 AL |
355 | void *stack = task_stack_page(tsk); |
356 | struct vm_struct *vm = task_stack_vm_area(tsk); | |
357 | ||
358 | BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0); | |
359 | ||
360 | if (vm) { | |
361 | int i; | |
362 | ||
363 | BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE); | |
364 | ||
365 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { | |
366 | mod_zone_page_state(page_zone(vm->pages[i]), | |
367 | NR_KERNEL_STACK_KB, | |
368 | PAGE_SIZE / 1024 * account); | |
369 | } | |
ba14a194 AL |
370 | } else { |
371 | /* | |
372 | * All stack pages are in the same zone and belong to the | |
373 | * same memcg. | |
374 | */ | |
375 | struct page *first_page = virt_to_page(stack); | |
376 | ||
377 | mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB, | |
378 | THREAD_SIZE / 1024 * account); | |
379 | ||
ed52be7b JW |
380 | mod_memcg_page_state(first_page, MEMCG_KERNEL_STACK_KB, |
381 | account * (THREAD_SIZE / 1024)); | |
ba14a194 | 382 | } |
c6a7f572 KM |
383 | } |
384 | ||
9b6f7e16 RG |
385 | static int memcg_charge_kernel_stack(struct task_struct *tsk) |
386 | { | |
387 | #ifdef CONFIG_VMAP_STACK | |
388 | struct vm_struct *vm = task_stack_vm_area(tsk); | |
389 | int ret; | |
390 | ||
391 | if (vm) { | |
392 | int i; | |
393 | ||
394 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { | |
395 | /* | |
396 | * If memcg_kmem_charge() fails, page->mem_cgroup | |
397 | * pointer is NULL, and both memcg_kmem_uncharge() | |
398 | * and mod_memcg_page_state() in free_thread_stack() | |
399 | * will ignore this page. So it's safe. | |
400 | */ | |
401 | ret = memcg_kmem_charge(vm->pages[i], GFP_KERNEL, 0); | |
402 | if (ret) | |
403 | return ret; | |
404 | ||
405 | mod_memcg_page_state(vm->pages[i], | |
406 | MEMCG_KERNEL_STACK_KB, | |
407 | PAGE_SIZE / 1024); | |
408 | } | |
409 | } | |
410 | #endif | |
411 | return 0; | |
412 | } | |
413 | ||
68f24b08 | 414 | static void release_task_stack(struct task_struct *tsk) |
1da177e4 | 415 | { |
405c0759 AL |
416 | if (WARN_ON(tsk->state != TASK_DEAD)) |
417 | return; /* Better to leak the stack than to free prematurely */ | |
418 | ||
ba14a194 | 419 | account_kernel_stack(tsk, -1); |
b235beea | 420 | arch_release_thread_stack(tsk->stack); |
ba14a194 | 421 | free_thread_stack(tsk); |
68f24b08 AL |
422 | tsk->stack = NULL; |
423 | #ifdef CONFIG_VMAP_STACK | |
424 | tsk->stack_vm_area = NULL; | |
425 | #endif | |
426 | } | |
427 | ||
428 | #ifdef CONFIG_THREAD_INFO_IN_TASK | |
429 | void put_task_stack(struct task_struct *tsk) | |
430 | { | |
431 | if (atomic_dec_and_test(&tsk->stack_refcount)) | |
432 | release_task_stack(tsk); | |
433 | } | |
434 | #endif | |
435 | ||
436 | void free_task(struct task_struct *tsk) | |
437 | { | |
438 | #ifndef CONFIG_THREAD_INFO_IN_TASK | |
439 | /* | |
440 | * The task is finally done with both the stack and thread_info, | |
441 | * so free both. | |
442 | */ | |
443 | release_task_stack(tsk); | |
444 | #else | |
445 | /* | |
446 | * If the task had a separate stack allocation, it should be gone | |
447 | * by now. | |
448 | */ | |
449 | WARN_ON_ONCE(atomic_read(&tsk->stack_refcount) != 0); | |
450 | #endif | |
23f78d4a | 451 | rt_mutex_debug_task_free(tsk); |
fb52607a | 452 | ftrace_graph_exit_task(tsk); |
e2cfabdf | 453 | put_seccomp_filter(tsk); |
f19b9f74 | 454 | arch_release_task_struct(tsk); |
1da5c46f ON |
455 | if (tsk->flags & PF_KTHREAD) |
456 | free_kthread_struct(tsk); | |
1da177e4 LT |
457 | free_task_struct(tsk); |
458 | } | |
459 | EXPORT_SYMBOL(free_task); | |
460 | ||
d70f2a14 AM |
461 | #ifdef CONFIG_MMU |
462 | static __latent_entropy int dup_mmap(struct mm_struct *mm, | |
463 | struct mm_struct *oldmm) | |
464 | { | |
465 | struct vm_area_struct *mpnt, *tmp, *prev, **pprev; | |
466 | struct rb_node **rb_link, *rb_parent; | |
467 | int retval; | |
468 | unsigned long charge; | |
469 | LIST_HEAD(uf); | |
470 | ||
471 | uprobe_start_dup_mmap(); | |
472 | if (down_write_killable(&oldmm->mmap_sem)) { | |
473 | retval = -EINTR; | |
474 | goto fail_uprobe_end; | |
475 | } | |
476 | flush_cache_dup_mm(oldmm); | |
477 | uprobe_dup_mmap(oldmm, mm); | |
478 | /* | |
479 | * Not linked in yet - no deadlock potential: | |
480 | */ | |
481 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
482 | ||
483 | /* No ordering required: file already has been exposed. */ | |
484 | RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); | |
485 | ||
486 | mm->total_vm = oldmm->total_vm; | |
487 | mm->data_vm = oldmm->data_vm; | |
488 | mm->exec_vm = oldmm->exec_vm; | |
489 | mm->stack_vm = oldmm->stack_vm; | |
490 | ||
491 | rb_link = &mm->mm_rb.rb_node; | |
492 | rb_parent = NULL; | |
493 | pprev = &mm->mmap; | |
494 | retval = ksm_fork(mm, oldmm); | |
495 | if (retval) | |
496 | goto out; | |
497 | retval = khugepaged_fork(mm, oldmm); | |
498 | if (retval) | |
499 | goto out; | |
500 | ||
501 | prev = NULL; | |
502 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { | |
503 | struct file *file; | |
504 | ||
505 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
506 | vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt)); | |
507 | continue; | |
508 | } | |
509 | charge = 0; | |
655c79bb TH |
510 | /* |
511 | * Don't duplicate many vmas if we've been oom-killed (for | |
512 | * example) | |
513 | */ | |
514 | if (fatal_signal_pending(current)) { | |
515 | retval = -EINTR; | |
516 | goto out; | |
517 | } | |
d70f2a14 AM |
518 | if (mpnt->vm_flags & VM_ACCOUNT) { |
519 | unsigned long len = vma_pages(mpnt); | |
520 | ||
521 | if (security_vm_enough_memory_mm(oldmm, len)) /* sic */ | |
522 | goto fail_nomem; | |
523 | charge = len; | |
524 | } | |
3928d4f5 | 525 | tmp = vm_area_dup(mpnt); |
d70f2a14 AM |
526 | if (!tmp) |
527 | goto fail_nomem; | |
d70f2a14 AM |
528 | retval = vma_dup_policy(mpnt, tmp); |
529 | if (retval) | |
530 | goto fail_nomem_policy; | |
531 | tmp->vm_mm = mm; | |
532 | retval = dup_userfaultfd(tmp, &uf); | |
533 | if (retval) | |
534 | goto fail_nomem_anon_vma_fork; | |
535 | if (tmp->vm_flags & VM_WIPEONFORK) { | |
536 | /* VM_WIPEONFORK gets a clean slate in the child. */ | |
537 | tmp->anon_vma = NULL; | |
538 | if (anon_vma_prepare(tmp)) | |
539 | goto fail_nomem_anon_vma_fork; | |
540 | } else if (anon_vma_fork(tmp, mpnt)) | |
541 | goto fail_nomem_anon_vma_fork; | |
542 | tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT); | |
543 | tmp->vm_next = tmp->vm_prev = NULL; | |
544 | file = tmp->vm_file; | |
545 | if (file) { | |
546 | struct inode *inode = file_inode(file); | |
547 | struct address_space *mapping = file->f_mapping; | |
548 | ||
549 | get_file(file); | |
550 | if (tmp->vm_flags & VM_DENYWRITE) | |
551 | atomic_dec(&inode->i_writecount); | |
552 | i_mmap_lock_write(mapping); | |
553 | if (tmp->vm_flags & VM_SHARED) | |
554 | atomic_inc(&mapping->i_mmap_writable); | |
555 | flush_dcache_mmap_lock(mapping); | |
556 | /* insert tmp into the share list, just after mpnt */ | |
557 | vma_interval_tree_insert_after(tmp, mpnt, | |
558 | &mapping->i_mmap); | |
559 | flush_dcache_mmap_unlock(mapping); | |
560 | i_mmap_unlock_write(mapping); | |
561 | } | |
562 | ||
563 | /* | |
564 | * Clear hugetlb-related page reserves for children. This only | |
565 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
566 | * are not guaranteed to succeed, even if read-only | |
567 | */ | |
568 | if (is_vm_hugetlb_page(tmp)) | |
569 | reset_vma_resv_huge_pages(tmp); | |
570 | ||
571 | /* | |
572 | * Link in the new vma and copy the page table entries. | |
573 | */ | |
574 | *pprev = tmp; | |
575 | pprev = &tmp->vm_next; | |
576 | tmp->vm_prev = prev; | |
577 | prev = tmp; | |
578 | ||
579 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
580 | rb_link = &tmp->vm_rb.rb_right; | |
581 | rb_parent = &tmp->vm_rb; | |
582 | ||
583 | mm->map_count++; | |
584 | if (!(tmp->vm_flags & VM_WIPEONFORK)) | |
585 | retval = copy_page_range(mm, oldmm, mpnt); | |
586 | ||
587 | if (tmp->vm_ops && tmp->vm_ops->open) | |
588 | tmp->vm_ops->open(tmp); | |
589 | ||
590 | if (retval) | |
591 | goto out; | |
592 | } | |
593 | /* a new mm has just been created */ | |
1ed0cc5a | 594 | retval = arch_dup_mmap(oldmm, mm); |
d70f2a14 AM |
595 | out: |
596 | up_write(&mm->mmap_sem); | |
597 | flush_tlb_mm(oldmm); | |
598 | up_write(&oldmm->mmap_sem); | |
599 | dup_userfaultfd_complete(&uf); | |
600 | fail_uprobe_end: | |
601 | uprobe_end_dup_mmap(); | |
602 | return retval; | |
603 | fail_nomem_anon_vma_fork: | |
604 | mpol_put(vma_policy(tmp)); | |
605 | fail_nomem_policy: | |
3928d4f5 | 606 | vm_area_free(tmp); |
d70f2a14 AM |
607 | fail_nomem: |
608 | retval = -ENOMEM; | |
609 | vm_unacct_memory(charge); | |
610 | goto out; | |
611 | } | |
612 | ||
613 | static inline int mm_alloc_pgd(struct mm_struct *mm) | |
614 | { | |
615 | mm->pgd = pgd_alloc(mm); | |
616 | if (unlikely(!mm->pgd)) | |
617 | return -ENOMEM; | |
618 | return 0; | |
619 | } | |
620 | ||
621 | static inline void mm_free_pgd(struct mm_struct *mm) | |
622 | { | |
623 | pgd_free(mm, mm->pgd); | |
624 | } | |
625 | #else | |
626 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) | |
627 | { | |
628 | down_write(&oldmm->mmap_sem); | |
629 | RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); | |
630 | up_write(&oldmm->mmap_sem); | |
631 | return 0; | |
632 | } | |
633 | #define mm_alloc_pgd(mm) (0) | |
634 | #define mm_free_pgd(mm) | |
635 | #endif /* CONFIG_MMU */ | |
636 | ||
637 | static void check_mm(struct mm_struct *mm) | |
638 | { | |
639 | int i; | |
640 | ||
641 | for (i = 0; i < NR_MM_COUNTERS; i++) { | |
642 | long x = atomic_long_read(&mm->rss_stat.count[i]); | |
643 | ||
644 | if (unlikely(x)) | |
645 | printk(KERN_ALERT "BUG: Bad rss-counter state " | |
646 | "mm:%p idx:%d val:%ld\n", mm, i, x); | |
647 | } | |
648 | ||
649 | if (mm_pgtables_bytes(mm)) | |
650 | pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n", | |
651 | mm_pgtables_bytes(mm)); | |
652 | ||
653 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS | |
654 | VM_BUG_ON_MM(mm->pmd_huge_pte, mm); | |
655 | #endif | |
656 | } | |
657 | ||
658 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) | |
659 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
660 | ||
661 | /* | |
662 | * Called when the last reference to the mm | |
663 | * is dropped: either by a lazy thread or by | |
664 | * mmput. Free the page directory and the mm. | |
665 | */ | |
d34bc48f | 666 | void __mmdrop(struct mm_struct *mm) |
d70f2a14 AM |
667 | { |
668 | BUG_ON(mm == &init_mm); | |
3eda69c9 MR |
669 | WARN_ON_ONCE(mm == current->mm); |
670 | WARN_ON_ONCE(mm == current->active_mm); | |
d70f2a14 AM |
671 | mm_free_pgd(mm); |
672 | destroy_context(mm); | |
673 | hmm_mm_destroy(mm); | |
674 | mmu_notifier_mm_destroy(mm); | |
675 | check_mm(mm); | |
676 | put_user_ns(mm->user_ns); | |
677 | free_mm(mm); | |
678 | } | |
d34bc48f | 679 | EXPORT_SYMBOL_GPL(__mmdrop); |
d70f2a14 AM |
680 | |
681 | static void mmdrop_async_fn(struct work_struct *work) | |
682 | { | |
683 | struct mm_struct *mm; | |
684 | ||
685 | mm = container_of(work, struct mm_struct, async_put_work); | |
686 | __mmdrop(mm); | |
687 | } | |
688 | ||
689 | static void mmdrop_async(struct mm_struct *mm) | |
690 | { | |
691 | if (unlikely(atomic_dec_and_test(&mm->mm_count))) { | |
692 | INIT_WORK(&mm->async_put_work, mmdrop_async_fn); | |
693 | schedule_work(&mm->async_put_work); | |
694 | } | |
695 | } | |
696 | ||
ea6d290c ON |
697 | static inline void free_signal_struct(struct signal_struct *sig) |
698 | { | |
97101eb4 | 699 | taskstats_tgid_free(sig); |
1c5354de | 700 | sched_autogroup_exit(sig); |
7283094e MH |
701 | /* |
702 | * __mmdrop is not safe to call from softirq context on x86 due to | |
703 | * pgd_dtor so postpone it to the async context | |
704 | */ | |
26db62f1 | 705 | if (sig->oom_mm) |
7283094e | 706 | mmdrop_async(sig->oom_mm); |
ea6d290c ON |
707 | kmem_cache_free(signal_cachep, sig); |
708 | } | |
709 | ||
710 | static inline void put_signal_struct(struct signal_struct *sig) | |
711 | { | |
1c5354de | 712 | if (atomic_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
713 | free_signal_struct(sig); |
714 | } | |
715 | ||
158d9ebd | 716 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 717 | { |
270f722d | 718 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
719 | WARN_ON(atomic_read(&tsk->usage)); |
720 | WARN_ON(tsk == current); | |
721 | ||
2e91fa7f | 722 | cgroup_free(tsk); |
156654f4 | 723 | task_numa_free(tsk); |
1a2a4d06 | 724 | security_task_free(tsk); |
e0e81739 | 725 | exit_creds(tsk); |
35df17c5 | 726 | delayacct_tsk_free(tsk); |
ea6d290c | 727 | put_signal_struct(tsk->signal); |
1da177e4 LT |
728 | |
729 | if (!profile_handoff_task(tsk)) | |
730 | free_task(tsk); | |
731 | } | |
77c100c8 | 732 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 733 | |
6c0a9fa6 | 734 | void __init __weak arch_task_cache_init(void) { } |
61c4628b | 735 | |
ff691f6e HS |
736 | /* |
737 | * set_max_threads | |
738 | */ | |
16db3d3f | 739 | static void set_max_threads(unsigned int max_threads_suggested) |
ff691f6e | 740 | { |
ac1b398d | 741 | u64 threads; |
ff691f6e HS |
742 | |
743 | /* | |
ac1b398d HS |
744 | * The number of threads shall be limited such that the thread |
745 | * structures may only consume a small part of the available memory. | |
ff691f6e | 746 | */ |
ac1b398d HS |
747 | if (fls64(totalram_pages) + fls64(PAGE_SIZE) > 64) |
748 | threads = MAX_THREADS; | |
749 | else | |
750 | threads = div64_u64((u64) totalram_pages * (u64) PAGE_SIZE, | |
751 | (u64) THREAD_SIZE * 8UL); | |
752 | ||
16db3d3f HS |
753 | if (threads > max_threads_suggested) |
754 | threads = max_threads_suggested; | |
755 | ||
ac1b398d | 756 | max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS); |
ff691f6e HS |
757 | } |
758 | ||
5aaeb5c0 IM |
759 | #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT |
760 | /* Initialized by the architecture: */ | |
761 | int arch_task_struct_size __read_mostly; | |
762 | #endif | |
0c8c0f03 | 763 | |
5905429a KC |
764 | static void task_struct_whitelist(unsigned long *offset, unsigned long *size) |
765 | { | |
766 | /* Fetch thread_struct whitelist for the architecture. */ | |
767 | arch_thread_struct_whitelist(offset, size); | |
768 | ||
769 | /* | |
770 | * Handle zero-sized whitelist or empty thread_struct, otherwise | |
771 | * adjust offset to position of thread_struct in task_struct. | |
772 | */ | |
773 | if (unlikely(*size == 0)) | |
774 | *offset = 0; | |
775 | else | |
776 | *offset += offsetof(struct task_struct, thread); | |
777 | } | |
778 | ||
ff691f6e | 779 | void __init fork_init(void) |
1da177e4 | 780 | { |
25f9c081 | 781 | int i; |
f5e10287 | 782 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
1da177e4 | 783 | #ifndef ARCH_MIN_TASKALIGN |
e274795e | 784 | #define ARCH_MIN_TASKALIGN 0 |
1da177e4 | 785 | #endif |
95cb64c1 | 786 | int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN); |
5905429a | 787 | unsigned long useroffset, usersize; |
e274795e | 788 | |
1da177e4 | 789 | /* create a slab on which task_structs can be allocated */ |
5905429a KC |
790 | task_struct_whitelist(&useroffset, &usersize); |
791 | task_struct_cachep = kmem_cache_create_usercopy("task_struct", | |
e274795e | 792 | arch_task_struct_size, align, |
5905429a KC |
793 | SLAB_PANIC|SLAB_ACCOUNT, |
794 | useroffset, usersize, NULL); | |
1da177e4 LT |
795 | #endif |
796 | ||
61c4628b SS |
797 | /* do the arch specific task caches init */ |
798 | arch_task_cache_init(); | |
799 | ||
16db3d3f | 800 | set_max_threads(MAX_THREADS); |
1da177e4 LT |
801 | |
802 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
803 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
804 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
805 | init_task.signal->rlim[RLIMIT_NPROC]; | |
b376c3e1 | 806 | |
25f9c081 EB |
807 | for (i = 0; i < UCOUNT_COUNTS; i++) { |
808 | init_user_ns.ucount_max[i] = max_threads/2; | |
809 | } | |
19659c59 HR |
810 | |
811 | #ifdef CONFIG_VMAP_STACK | |
812 | cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", | |
813 | NULL, free_vm_stack_cache); | |
814 | #endif | |
b09be676 BP |
815 | |
816 | lockdep_init_task(&init_task); | |
1da177e4 LT |
817 | } |
818 | ||
52f5684c | 819 | int __weak arch_dup_task_struct(struct task_struct *dst, |
61c4628b SS |
820 | struct task_struct *src) |
821 | { | |
822 | *dst = *src; | |
823 | return 0; | |
824 | } | |
825 | ||
d4311ff1 AT |
826 | void set_task_stack_end_magic(struct task_struct *tsk) |
827 | { | |
828 | unsigned long *stackend; | |
829 | ||
830 | stackend = end_of_stack(tsk); | |
831 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
832 | } | |
833 | ||
725fc629 | 834 | static struct task_struct *dup_task_struct(struct task_struct *orig, int node) |
1da177e4 LT |
835 | { |
836 | struct task_struct *tsk; | |
b235beea | 837 | unsigned long *stack; |
ba14a194 | 838 | struct vm_struct *stack_vm_area; |
3e26c149 | 839 | int err; |
1da177e4 | 840 | |
725fc629 AK |
841 | if (node == NUMA_NO_NODE) |
842 | node = tsk_fork_get_node(orig); | |
504f52b5 | 843 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
844 | if (!tsk) |
845 | return NULL; | |
846 | ||
b235beea LT |
847 | stack = alloc_thread_stack_node(tsk, node); |
848 | if (!stack) | |
f19b9f74 | 849 | goto free_tsk; |
1da177e4 | 850 | |
9b6f7e16 RG |
851 | if (memcg_charge_kernel_stack(tsk)) |
852 | goto free_stack; | |
853 | ||
ba14a194 AL |
854 | stack_vm_area = task_stack_vm_area(tsk); |
855 | ||
fb0a685c | 856 | err = arch_dup_task_struct(tsk, orig); |
ba14a194 AL |
857 | |
858 | /* | |
859 | * arch_dup_task_struct() clobbers the stack-related fields. Make | |
860 | * sure they're properly initialized before using any stack-related | |
861 | * functions again. | |
862 | */ | |
863 | tsk->stack = stack; | |
864 | #ifdef CONFIG_VMAP_STACK | |
865 | tsk->stack_vm_area = stack_vm_area; | |
866 | #endif | |
68f24b08 AL |
867 | #ifdef CONFIG_THREAD_INFO_IN_TASK |
868 | atomic_set(&tsk->stack_refcount, 1); | |
869 | #endif | |
ba14a194 | 870 | |
164c33c6 | 871 | if (err) |
b235beea | 872 | goto free_stack; |
164c33c6 | 873 | |
dbd95212 KC |
874 | #ifdef CONFIG_SECCOMP |
875 | /* | |
876 | * We must handle setting up seccomp filters once we're under | |
877 | * the sighand lock in case orig has changed between now and | |
878 | * then. Until then, filter must be NULL to avoid messing up | |
879 | * the usage counts on the error path calling free_task. | |
880 | */ | |
881 | tsk->seccomp.filter = NULL; | |
882 | #endif | |
87bec58a AM |
883 | |
884 | setup_thread_stack(tsk, orig); | |
8e7cac79 | 885 | clear_user_return_notifier(tsk); |
f26f9aff | 886 | clear_tsk_need_resched(tsk); |
d4311ff1 | 887 | set_task_stack_end_magic(tsk); |
1da177e4 | 888 | |
050e9baa | 889 | #ifdef CONFIG_STACKPROTECTOR |
7cd815bc | 890 | tsk->stack_canary = get_random_canary(); |
0a425405 AV |
891 | #endif |
892 | ||
fb0a685c DRO |
893 | /* |
894 | * One for us, one for whoever does the "release_task()" (usually | |
895 | * parent) | |
896 | */ | |
897 | atomic_set(&tsk->usage, 2); | |
6c5c9341 | 898 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 899 | tsk->btrace_seq = 0; |
6c5c9341 | 900 | #endif |
a0aa7f68 | 901 | tsk->splice_pipe = NULL; |
5640f768 | 902 | tsk->task_frag.page = NULL; |
093e5840 | 903 | tsk->wake_q.next = NULL; |
c6a7f572 | 904 | |
ba14a194 | 905 | account_kernel_stack(tsk, 1); |
c6a7f572 | 906 | |
5c9a8750 DV |
907 | kcov_task_init(tsk); |
908 | ||
e41d5818 DV |
909 | #ifdef CONFIG_FAULT_INJECTION |
910 | tsk->fail_nth = 0; | |
911 | #endif | |
912 | ||
2c323017 JB |
913 | #ifdef CONFIG_BLK_CGROUP |
914 | tsk->throttle_queue = NULL; | |
915 | tsk->use_memdelay = 0; | |
916 | #endif | |
917 | ||
d46eb14b SB |
918 | #ifdef CONFIG_MEMCG |
919 | tsk->active_memcg = NULL; | |
920 | #endif | |
1da177e4 | 921 | return tsk; |
61c4628b | 922 | |
b235beea | 923 | free_stack: |
ba14a194 | 924 | free_thread_stack(tsk); |
f19b9f74 | 925 | free_tsk: |
61c4628b SS |
926 | free_task_struct(tsk); |
927 | return NULL; | |
1da177e4 LT |
928 | } |
929 | ||
23ff4440 | 930 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 931 | |
4cb0e11b HK |
932 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
933 | ||
934 | static int __init coredump_filter_setup(char *s) | |
935 | { | |
936 | default_dump_filter = | |
937 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
938 | MMF_DUMP_FILTER_MASK; | |
939 | return 1; | |
940 | } | |
941 | ||
942 | __setup("coredump_filter=", coredump_filter_setup); | |
943 | ||
1da177e4 LT |
944 | #include <linux/init_task.h> |
945 | ||
858f0993 AD |
946 | static void mm_init_aio(struct mm_struct *mm) |
947 | { | |
948 | #ifdef CONFIG_AIO | |
949 | spin_lock_init(&mm->ioctx_lock); | |
db446a08 | 950 | mm->ioctx_table = NULL; |
858f0993 AD |
951 | #endif |
952 | } | |
953 | ||
33144e84 VD |
954 | static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) |
955 | { | |
956 | #ifdef CONFIG_MEMCG | |
957 | mm->owner = p; | |
958 | #endif | |
959 | } | |
960 | ||
355627f5 EB |
961 | static void mm_init_uprobes_state(struct mm_struct *mm) |
962 | { | |
963 | #ifdef CONFIG_UPROBES | |
964 | mm->uprobes_state.xol_area = NULL; | |
965 | #endif | |
966 | } | |
967 | ||
bfedb589 EB |
968 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, |
969 | struct user_namespace *user_ns) | |
1da177e4 | 970 | { |
41f727fd VD |
971 | mm->mmap = NULL; |
972 | mm->mm_rb = RB_ROOT; | |
973 | mm->vmacache_seqnum = 0; | |
1da177e4 LT |
974 | atomic_set(&mm->mm_users, 1); |
975 | atomic_set(&mm->mm_count, 1); | |
976 | init_rwsem(&mm->mmap_sem); | |
977 | INIT_LIST_HEAD(&mm->mmlist); | |
999d9fc1 | 978 | mm->core_state = NULL; |
af5b0f6a | 979 | mm_pgtables_bytes_init(mm); |
41f727fd VD |
980 | mm->map_count = 0; |
981 | mm->locked_vm = 0; | |
ce65cefa | 982 | mm->pinned_vm = 0; |
d559db08 | 983 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 984 | spin_lock_init(&mm->page_table_lock); |
88aa7cc6 | 985 | spin_lock_init(&mm->arg_lock); |
41f727fd | 986 | mm_init_cpumask(mm); |
858f0993 | 987 | mm_init_aio(mm); |
cf475ad2 | 988 | mm_init_owner(mm, p); |
2b7e8665 | 989 | RCU_INIT_POINTER(mm->exe_file, NULL); |
41f727fd | 990 | mmu_notifier_mm_init(mm); |
133ff0ea | 991 | hmm_mm_init(mm); |
16af97dc | 992 | init_tlb_flush_pending(mm); |
41f727fd VD |
993 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
994 | mm->pmd_huge_pte = NULL; | |
995 | #endif | |
355627f5 | 996 | mm_init_uprobes_state(mm); |
1da177e4 | 997 | |
a0715cc2 AT |
998 | if (current->mm) { |
999 | mm->flags = current->mm->flags & MMF_INIT_MASK; | |
1000 | mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; | |
1001 | } else { | |
1002 | mm->flags = default_dump_filter; | |
1da177e4 | 1003 | mm->def_flags = 0; |
a0715cc2 AT |
1004 | } |
1005 | ||
41f727fd VD |
1006 | if (mm_alloc_pgd(mm)) |
1007 | goto fail_nopgd; | |
1008 | ||
1009 | if (init_new_context(p, mm)) | |
1010 | goto fail_nocontext; | |
78fb7466 | 1011 | |
bfedb589 | 1012 | mm->user_ns = get_user_ns(user_ns); |
41f727fd VD |
1013 | return mm; |
1014 | ||
1015 | fail_nocontext: | |
1016 | mm_free_pgd(mm); | |
1017 | fail_nopgd: | |
1da177e4 LT |
1018 | free_mm(mm); |
1019 | return NULL; | |
1020 | } | |
1021 | ||
1022 | /* | |
1023 | * Allocate and initialize an mm_struct. | |
1024 | */ | |
fb0a685c | 1025 | struct mm_struct *mm_alloc(void) |
1da177e4 | 1026 | { |
fb0a685c | 1027 | struct mm_struct *mm; |
1da177e4 LT |
1028 | |
1029 | mm = allocate_mm(); | |
de03c72c KM |
1030 | if (!mm) |
1031 | return NULL; | |
1032 | ||
1033 | memset(mm, 0, sizeof(*mm)); | |
bfedb589 | 1034 | return mm_init(mm, current, current_user_ns()); |
1da177e4 LT |
1035 | } |
1036 | ||
ec8d7c14 MH |
1037 | static inline void __mmput(struct mm_struct *mm) |
1038 | { | |
1039 | VM_BUG_ON(atomic_read(&mm->mm_users)); | |
1040 | ||
1041 | uprobe_clear_state(mm); | |
1042 | exit_aio(mm); | |
1043 | ksm_exit(mm); | |
1044 | khugepaged_exit(mm); /* must run before exit_mmap */ | |
1045 | exit_mmap(mm); | |
6fcb52a5 | 1046 | mm_put_huge_zero_page(mm); |
ec8d7c14 MH |
1047 | set_mm_exe_file(mm, NULL); |
1048 | if (!list_empty(&mm->mmlist)) { | |
1049 | spin_lock(&mmlist_lock); | |
1050 | list_del(&mm->mmlist); | |
1051 | spin_unlock(&mmlist_lock); | |
1052 | } | |
1053 | if (mm->binfmt) | |
1054 | module_put(mm->binfmt->module); | |
1055 | mmdrop(mm); | |
1056 | } | |
1057 | ||
1da177e4 LT |
1058 | /* |
1059 | * Decrement the use count and release all resources for an mm. | |
1060 | */ | |
1061 | void mmput(struct mm_struct *mm) | |
1062 | { | |
0ae26f1b AM |
1063 | might_sleep(); |
1064 | ||
ec8d7c14 MH |
1065 | if (atomic_dec_and_test(&mm->mm_users)) |
1066 | __mmput(mm); | |
1067 | } | |
1068 | EXPORT_SYMBOL_GPL(mmput); | |
1069 | ||
a1b2289c SY |
1070 | #ifdef CONFIG_MMU |
1071 | static void mmput_async_fn(struct work_struct *work) | |
1072 | { | |
1073 | struct mm_struct *mm = container_of(work, struct mm_struct, | |
1074 | async_put_work); | |
1075 | ||
1076 | __mmput(mm); | |
1077 | } | |
1078 | ||
1079 | void mmput_async(struct mm_struct *mm) | |
1080 | { | |
1081 | if (atomic_dec_and_test(&mm->mm_users)) { | |
1082 | INIT_WORK(&mm->async_put_work, mmput_async_fn); | |
1083 | schedule_work(&mm->async_put_work); | |
1084 | } | |
1085 | } | |
1086 | #endif | |
1087 | ||
90f31d0e KK |
1088 | /** |
1089 | * set_mm_exe_file - change a reference to the mm's executable file | |
1090 | * | |
1091 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe). | |
1092 | * | |
6e399cd1 DB |
1093 | * Main users are mmput() and sys_execve(). Callers prevent concurrent |
1094 | * invocations: in mmput() nobody alive left, in execve task is single | |
1095 | * threaded. sys_prctl(PR_SET_MM_MAP/EXE_FILE) also needs to set the | |
1096 | * mm->exe_file, but does so without using set_mm_exe_file() in order | |
1097 | * to do avoid the need for any locks. | |
90f31d0e | 1098 | */ |
38646013 JS |
1099 | void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) |
1100 | { | |
6e399cd1 DB |
1101 | struct file *old_exe_file; |
1102 | ||
1103 | /* | |
1104 | * It is safe to dereference the exe_file without RCU as | |
1105 | * this function is only called if nobody else can access | |
1106 | * this mm -- see comment above for justification. | |
1107 | */ | |
1108 | old_exe_file = rcu_dereference_raw(mm->exe_file); | |
90f31d0e | 1109 | |
38646013 JS |
1110 | if (new_exe_file) |
1111 | get_file(new_exe_file); | |
90f31d0e KK |
1112 | rcu_assign_pointer(mm->exe_file, new_exe_file); |
1113 | if (old_exe_file) | |
1114 | fput(old_exe_file); | |
38646013 JS |
1115 | } |
1116 | ||
90f31d0e KK |
1117 | /** |
1118 | * get_mm_exe_file - acquire a reference to the mm's executable file | |
1119 | * | |
1120 | * Returns %NULL if mm has no associated executable file. | |
1121 | * User must release file via fput(). | |
1122 | */ | |
38646013 JS |
1123 | struct file *get_mm_exe_file(struct mm_struct *mm) |
1124 | { | |
1125 | struct file *exe_file; | |
1126 | ||
90f31d0e KK |
1127 | rcu_read_lock(); |
1128 | exe_file = rcu_dereference(mm->exe_file); | |
1129 | if (exe_file && !get_file_rcu(exe_file)) | |
1130 | exe_file = NULL; | |
1131 | rcu_read_unlock(); | |
38646013 JS |
1132 | return exe_file; |
1133 | } | |
11163348 | 1134 | EXPORT_SYMBOL(get_mm_exe_file); |
38646013 | 1135 | |
cd81a917 MG |
1136 | /** |
1137 | * get_task_exe_file - acquire a reference to the task's executable file | |
1138 | * | |
1139 | * Returns %NULL if task's mm (if any) has no associated executable file or | |
1140 | * this is a kernel thread with borrowed mm (see the comment above get_task_mm). | |
1141 | * User must release file via fput(). | |
1142 | */ | |
1143 | struct file *get_task_exe_file(struct task_struct *task) | |
1144 | { | |
1145 | struct file *exe_file = NULL; | |
1146 | struct mm_struct *mm; | |
1147 | ||
1148 | task_lock(task); | |
1149 | mm = task->mm; | |
1150 | if (mm) { | |
1151 | if (!(task->flags & PF_KTHREAD)) | |
1152 | exe_file = get_mm_exe_file(mm); | |
1153 | } | |
1154 | task_unlock(task); | |
1155 | return exe_file; | |
1156 | } | |
1157 | EXPORT_SYMBOL(get_task_exe_file); | |
38646013 | 1158 | |
1da177e4 LT |
1159 | /** |
1160 | * get_task_mm - acquire a reference to the task's mm | |
1161 | * | |
246bb0b1 | 1162 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
1163 | * this kernel workthread has transiently adopted a user mm with use_mm, |
1164 | * to do its AIO) is not set and if so returns a reference to it, after | |
1165 | * bumping up the use count. User must release the mm via mmput() | |
1166 | * after use. Typically used by /proc and ptrace. | |
1167 | */ | |
1168 | struct mm_struct *get_task_mm(struct task_struct *task) | |
1169 | { | |
1170 | struct mm_struct *mm; | |
1171 | ||
1172 | task_lock(task); | |
1173 | mm = task->mm; | |
1174 | if (mm) { | |
246bb0b1 | 1175 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
1176 | mm = NULL; |
1177 | else | |
3fce371b | 1178 | mmget(mm); |
1da177e4 LT |
1179 | } |
1180 | task_unlock(task); | |
1181 | return mm; | |
1182 | } | |
1183 | EXPORT_SYMBOL_GPL(get_task_mm); | |
1184 | ||
8cdb878d CY |
1185 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) |
1186 | { | |
1187 | struct mm_struct *mm; | |
1188 | int err; | |
1189 | ||
1190 | err = mutex_lock_killable(&task->signal->cred_guard_mutex); | |
1191 | if (err) | |
1192 | return ERR_PTR(err); | |
1193 | ||
1194 | mm = get_task_mm(task); | |
1195 | if (mm && mm != current->mm && | |
1196 | !ptrace_may_access(task, mode)) { | |
1197 | mmput(mm); | |
1198 | mm = ERR_PTR(-EACCES); | |
1199 | } | |
1200 | mutex_unlock(&task->signal->cred_guard_mutex); | |
1201 | ||
1202 | return mm; | |
1203 | } | |
1204 | ||
57b59c4a | 1205 | static void complete_vfork_done(struct task_struct *tsk) |
c415c3b4 | 1206 | { |
d68b46fe | 1207 | struct completion *vfork; |
c415c3b4 | 1208 | |
d68b46fe ON |
1209 | task_lock(tsk); |
1210 | vfork = tsk->vfork_done; | |
1211 | if (likely(vfork)) { | |
1212 | tsk->vfork_done = NULL; | |
1213 | complete(vfork); | |
1214 | } | |
1215 | task_unlock(tsk); | |
1216 | } | |
1217 | ||
1218 | static int wait_for_vfork_done(struct task_struct *child, | |
1219 | struct completion *vfork) | |
1220 | { | |
1221 | int killed; | |
1222 | ||
1223 | freezer_do_not_count(); | |
1224 | killed = wait_for_completion_killable(vfork); | |
1225 | freezer_count(); | |
1226 | ||
1227 | if (killed) { | |
1228 | task_lock(child); | |
1229 | child->vfork_done = NULL; | |
1230 | task_unlock(child); | |
1231 | } | |
1232 | ||
1233 | put_task_struct(child); | |
1234 | return killed; | |
c415c3b4 ON |
1235 | } |
1236 | ||
1da177e4 LT |
1237 | /* Please note the differences between mmput and mm_release. |
1238 | * mmput is called whenever we stop holding onto a mm_struct, | |
1239 | * error success whatever. | |
1240 | * | |
1241 | * mm_release is called after a mm_struct has been removed | |
1242 | * from the current process. | |
1243 | * | |
1244 | * This difference is important for error handling, when we | |
1245 | * only half set up a mm_struct for a new process and need to restore | |
1246 | * the old one. Because we mmput the new mm_struct before | |
1247 | * restoring the old one. . . | |
1248 | * Eric Biederman 10 January 1998 | |
1249 | */ | |
1250 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
1251 | { | |
8141c7f3 LT |
1252 | /* Get rid of any futexes when releasing the mm */ |
1253 | #ifdef CONFIG_FUTEX | |
fc6b177d | 1254 | if (unlikely(tsk->robust_list)) { |
8141c7f3 | 1255 | exit_robust_list(tsk); |
fc6b177d PZ |
1256 | tsk->robust_list = NULL; |
1257 | } | |
8141c7f3 | 1258 | #ifdef CONFIG_COMPAT |
fc6b177d | 1259 | if (unlikely(tsk->compat_robust_list)) { |
8141c7f3 | 1260 | compat_exit_robust_list(tsk); |
fc6b177d PZ |
1261 | tsk->compat_robust_list = NULL; |
1262 | } | |
8141c7f3 | 1263 | #endif |
322a2c10 TG |
1264 | if (unlikely(!list_empty(&tsk->pi_state_list))) |
1265 | exit_pi_state_list(tsk); | |
8141c7f3 LT |
1266 | #endif |
1267 | ||
0326f5a9 SD |
1268 | uprobe_free_utask(tsk); |
1269 | ||
1da177e4 LT |
1270 | /* Get rid of any cached register state */ |
1271 | deactivate_mm(tsk, mm); | |
1272 | ||
fec1d011 | 1273 | /* |
735f2770 MH |
1274 | * Signal userspace if we're not exiting with a core dump |
1275 | * because we want to leave the value intact for debugging | |
1276 | * purposes. | |
fec1d011 | 1277 | */ |
9c8a8228 | 1278 | if (tsk->clear_child_tid) { |
735f2770 | 1279 | if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) && |
9c8a8228 ED |
1280 | atomic_read(&mm->mm_users) > 1) { |
1281 | /* | |
1282 | * We don't check the error code - if userspace has | |
1283 | * not set up a proper pointer then tough luck. | |
1284 | */ | |
1285 | put_user(0, tsk->clear_child_tid); | |
2de0db99 DB |
1286 | do_futex(tsk->clear_child_tid, FUTEX_WAKE, |
1287 | 1, NULL, NULL, 0, 0); | |
9c8a8228 | 1288 | } |
1da177e4 | 1289 | tsk->clear_child_tid = NULL; |
1da177e4 | 1290 | } |
f7505d64 KK |
1291 | |
1292 | /* | |
1293 | * All done, finally we can wake up parent and return this mm to him. | |
1294 | * Also kthread_stop() uses this completion for synchronization. | |
1295 | */ | |
1296 | if (tsk->vfork_done) | |
1297 | complete_vfork_done(tsk); | |
1da177e4 LT |
1298 | } |
1299 | ||
a0a7ec30 JD |
1300 | /* |
1301 | * Allocate a new mm structure and copy contents from the | |
1302 | * mm structure of the passed in task structure. | |
1303 | */ | |
ff252c1f | 1304 | static struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
1305 | { |
1306 | struct mm_struct *mm, *oldmm = current->mm; | |
1307 | int err; | |
1308 | ||
a0a7ec30 JD |
1309 | mm = allocate_mm(); |
1310 | if (!mm) | |
1311 | goto fail_nomem; | |
1312 | ||
1313 | memcpy(mm, oldmm, sizeof(*mm)); | |
1314 | ||
bfedb589 | 1315 | if (!mm_init(mm, tsk, mm->user_ns)) |
a0a7ec30 JD |
1316 | goto fail_nomem; |
1317 | ||
a0a7ec30 JD |
1318 | err = dup_mmap(mm, oldmm); |
1319 | if (err) | |
1320 | goto free_pt; | |
1321 | ||
1322 | mm->hiwater_rss = get_mm_rss(mm); | |
1323 | mm->hiwater_vm = mm->total_vm; | |
1324 | ||
801460d0 HS |
1325 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
1326 | goto free_pt; | |
1327 | ||
a0a7ec30 JD |
1328 | return mm; |
1329 | ||
1330 | free_pt: | |
801460d0 HS |
1331 | /* don't put binfmt in mmput, we haven't got module yet */ |
1332 | mm->binfmt = NULL; | |
a0a7ec30 JD |
1333 | mmput(mm); |
1334 | ||
1335 | fail_nomem: | |
1336 | return NULL; | |
a0a7ec30 JD |
1337 | } |
1338 | ||
fb0a685c | 1339 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1340 | { |
fb0a685c | 1341 | struct mm_struct *mm, *oldmm; |
1da177e4 LT |
1342 | int retval; |
1343 | ||
1344 | tsk->min_flt = tsk->maj_flt = 0; | |
1345 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
1346 | #ifdef CONFIG_DETECT_HUNG_TASK |
1347 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
a2e51445 | 1348 | tsk->last_switch_time = 0; |
17406b82 | 1349 | #endif |
1da177e4 LT |
1350 | |
1351 | tsk->mm = NULL; | |
1352 | tsk->active_mm = NULL; | |
1353 | ||
1354 | /* | |
1355 | * Are we cloning a kernel thread? | |
1356 | * | |
1357 | * We need to steal a active VM for that.. | |
1358 | */ | |
1359 | oldmm = current->mm; | |
1360 | if (!oldmm) | |
1361 | return 0; | |
1362 | ||
615d6e87 DB |
1363 | /* initialize the new vmacache entries */ |
1364 | vmacache_flush(tsk); | |
1365 | ||
1da177e4 | 1366 | if (clone_flags & CLONE_VM) { |
3fce371b | 1367 | mmget(oldmm); |
1da177e4 | 1368 | mm = oldmm; |
1da177e4 LT |
1369 | goto good_mm; |
1370 | } | |
1371 | ||
1372 | retval = -ENOMEM; | |
a0a7ec30 | 1373 | mm = dup_mm(tsk); |
1da177e4 LT |
1374 | if (!mm) |
1375 | goto fail_nomem; | |
1376 | ||
1da177e4 LT |
1377 | good_mm: |
1378 | tsk->mm = mm; | |
1379 | tsk->active_mm = mm; | |
1380 | return 0; | |
1381 | ||
1da177e4 LT |
1382 | fail_nomem: |
1383 | return retval; | |
1da177e4 LT |
1384 | } |
1385 | ||
a39bc516 | 1386 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1387 | { |
498052bb | 1388 | struct fs_struct *fs = current->fs; |
1da177e4 | 1389 | if (clone_flags & CLONE_FS) { |
498052bb | 1390 | /* tsk->fs is already what we want */ |
2a4419b5 | 1391 | spin_lock(&fs->lock); |
498052bb | 1392 | if (fs->in_exec) { |
2a4419b5 | 1393 | spin_unlock(&fs->lock); |
498052bb AV |
1394 | return -EAGAIN; |
1395 | } | |
1396 | fs->users++; | |
2a4419b5 | 1397 | spin_unlock(&fs->lock); |
1da177e4 LT |
1398 | return 0; |
1399 | } | |
498052bb | 1400 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
1401 | if (!tsk->fs) |
1402 | return -ENOMEM; | |
1403 | return 0; | |
1404 | } | |
1405 | ||
fb0a685c | 1406 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk) |
a016f338 JD |
1407 | { |
1408 | struct files_struct *oldf, *newf; | |
1409 | int error = 0; | |
1410 | ||
1411 | /* | |
1412 | * A background process may not have any files ... | |
1413 | */ | |
1414 | oldf = current->files; | |
1415 | if (!oldf) | |
1416 | goto out; | |
1417 | ||
1418 | if (clone_flags & CLONE_FILES) { | |
1419 | atomic_inc(&oldf->count); | |
1420 | goto out; | |
1421 | } | |
1422 | ||
a016f338 JD |
1423 | newf = dup_fd(oldf, &error); |
1424 | if (!newf) | |
1425 | goto out; | |
1426 | ||
1427 | tsk->files = newf; | |
1428 | error = 0; | |
1429 | out: | |
1430 | return error; | |
1431 | } | |
1432 | ||
fadad878 | 1433 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
1434 | { |
1435 | #ifdef CONFIG_BLOCK | |
1436 | struct io_context *ioc = current->io_context; | |
6e736be7 | 1437 | struct io_context *new_ioc; |
fd0928df JA |
1438 | |
1439 | if (!ioc) | |
1440 | return 0; | |
fadad878 JA |
1441 | /* |
1442 | * Share io context with parent, if CLONE_IO is set | |
1443 | */ | |
1444 | if (clone_flags & CLONE_IO) { | |
3d48749d TH |
1445 | ioc_task_link(ioc); |
1446 | tsk->io_context = ioc; | |
fadad878 | 1447 | } else if (ioprio_valid(ioc->ioprio)) { |
6e736be7 TH |
1448 | new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE); |
1449 | if (unlikely(!new_ioc)) | |
fd0928df JA |
1450 | return -ENOMEM; |
1451 | ||
6e736be7 | 1452 | new_ioc->ioprio = ioc->ioprio; |
11a3122f | 1453 | put_io_context(new_ioc); |
fd0928df JA |
1454 | } |
1455 | #endif | |
1456 | return 0; | |
1457 | } | |
1458 | ||
a39bc516 | 1459 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1460 | { |
1461 | struct sighand_struct *sig; | |
1462 | ||
60348802 | 1463 | if (clone_flags & CLONE_SIGHAND) { |
1da177e4 LT |
1464 | atomic_inc(¤t->sighand->count); |
1465 | return 0; | |
1466 | } | |
1467 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 1468 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
1469 | if (!sig) |
1470 | return -ENOMEM; | |
9d7fb042 | 1471 | |
1da177e4 | 1472 | atomic_set(&sig->count, 1); |
06e62a46 | 1473 | spin_lock_irq(¤t->sighand->siglock); |
1da177e4 | 1474 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); |
06e62a46 | 1475 | spin_unlock_irq(¤t->sighand->siglock); |
1da177e4 LT |
1476 | return 0; |
1477 | } | |
1478 | ||
a7e5328a | 1479 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 1480 | { |
d80e731e ON |
1481 | if (atomic_dec_and_test(&sighand->count)) { |
1482 | signalfd_cleanup(sighand); | |
392809b2 | 1483 | /* |
5f0d5a3a | 1484 | * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it |
392809b2 ON |
1485 | * without an RCU grace period, see __lock_task_sighand(). |
1486 | */ | |
c81addc9 | 1487 | kmem_cache_free(sighand_cachep, sighand); |
d80e731e | 1488 | } |
c81addc9 ON |
1489 | } |
1490 | ||
b18b6a9c | 1491 | #ifdef CONFIG_POSIX_TIMERS |
f06febc9 FM |
1492 | /* |
1493 | * Initialize POSIX timer handling for a thread group. | |
1494 | */ | |
1495 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
1496 | { | |
78d7d407 JS |
1497 | unsigned long cpu_limit; |
1498 | ||
316c1608 | 1499 | cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
78d7d407 | 1500 | if (cpu_limit != RLIM_INFINITY) { |
ebd7e7fc | 1501 | sig->cputime_expires.prof_exp = cpu_limit * NSEC_PER_SEC; |
d5c373eb | 1502 | sig->cputimer.running = true; |
6279a751 ON |
1503 | } |
1504 | ||
f06febc9 FM |
1505 | /* The timer lists. */ |
1506 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
1507 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
1508 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
1509 | } | |
b18b6a9c NP |
1510 | #else |
1511 | static inline void posix_cpu_timers_init_group(struct signal_struct *sig) { } | |
1512 | #endif | |
f06febc9 | 1513 | |
a39bc516 | 1514 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1515 | { |
1516 | struct signal_struct *sig; | |
1da177e4 | 1517 | |
4ab6c083 | 1518 | if (clone_flags & CLONE_THREAD) |
490dea45 | 1519 | return 0; |
490dea45 | 1520 | |
a56704ef | 1521 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
1522 | tsk->signal = sig; |
1523 | if (!sig) | |
1524 | return -ENOMEM; | |
1525 | ||
b3ac022c | 1526 | sig->nr_threads = 1; |
1da177e4 | 1527 | atomic_set(&sig->live, 1); |
b3ac022c | 1528 | atomic_set(&sig->sigcnt, 1); |
0c740d0a ON |
1529 | |
1530 | /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */ | |
1531 | sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node); | |
1532 | tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head); | |
1533 | ||
1da177e4 | 1534 | init_waitqueue_head(&sig->wait_chldexit); |
db51aecc | 1535 | sig->curr_target = tsk; |
1da177e4 | 1536 | init_sigpending(&sig->shared_pending); |
c3ad2c3b | 1537 | INIT_HLIST_HEAD(&sig->multiprocess); |
e78c3496 | 1538 | seqlock_init(&sig->stats_lock); |
9d7fb042 | 1539 | prev_cputime_init(&sig->prev_cputime); |
1da177e4 | 1540 | |
baa73d9e | 1541 | #ifdef CONFIG_POSIX_TIMERS |
b18b6a9c | 1542 | INIT_LIST_HEAD(&sig->posix_timers); |
c9cb2e3d | 1543 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 1544 | sig->real_timer.function = it_real_fn; |
baa73d9e | 1545 | #endif |
1da177e4 | 1546 | |
1da177e4 LT |
1547 | task_lock(current->group_leader); |
1548 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
1549 | task_unlock(current->group_leader); | |
1550 | ||
6279a751 ON |
1551 | posix_cpu_timers_init_group(sig); |
1552 | ||
522ed776 | 1553 | tty_audit_fork(sig); |
5091faa4 | 1554 | sched_autogroup_fork(sig); |
522ed776 | 1555 | |
a63d83f4 | 1556 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 1557 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 1558 | |
9b1bf12d KM |
1559 | mutex_init(&sig->cred_guard_mutex); |
1560 | ||
1da177e4 LT |
1561 | return 0; |
1562 | } | |
1563 | ||
dbd95212 KC |
1564 | static void copy_seccomp(struct task_struct *p) |
1565 | { | |
1566 | #ifdef CONFIG_SECCOMP | |
1567 | /* | |
1568 | * Must be called with sighand->lock held, which is common to | |
1569 | * all threads in the group. Holding cred_guard_mutex is not | |
1570 | * needed because this new task is not yet running and cannot | |
1571 | * be racing exec. | |
1572 | */ | |
69f6a34b | 1573 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 KC |
1574 | |
1575 | /* Ref-count the new filter user, and assign it. */ | |
1576 | get_seccomp_filter(current); | |
1577 | p->seccomp = current->seccomp; | |
1578 | ||
1579 | /* | |
1580 | * Explicitly enable no_new_privs here in case it got set | |
1581 | * between the task_struct being duplicated and holding the | |
1582 | * sighand lock. The seccomp state and nnp must be in sync. | |
1583 | */ | |
1584 | if (task_no_new_privs(current)) | |
1585 | task_set_no_new_privs(p); | |
1586 | ||
1587 | /* | |
1588 | * If the parent gained a seccomp mode after copying thread | |
1589 | * flags and between before we held the sighand lock, we have | |
1590 | * to manually enable the seccomp thread flag here. | |
1591 | */ | |
1592 | if (p->seccomp.mode != SECCOMP_MODE_DISABLED) | |
1593 | set_tsk_thread_flag(p, TIF_SECCOMP); | |
1594 | #endif | |
1595 | } | |
1596 | ||
17da2bd9 | 1597 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
1598 | { |
1599 | current->clear_child_tid = tidptr; | |
1600 | ||
b488893a | 1601 | return task_pid_vnr(current); |
1da177e4 LT |
1602 | } |
1603 | ||
a39bc516 | 1604 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 1605 | { |
1d615482 | 1606 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 1607 | #ifdef CONFIG_RT_MUTEXES |
a23ba907 | 1608 | p->pi_waiters = RB_ROOT_CACHED; |
e96a7705 | 1609 | p->pi_top_task = NULL; |
23f78d4a | 1610 | p->pi_blocked_on = NULL; |
23f78d4a IM |
1611 | #endif |
1612 | } | |
1613 | ||
b18b6a9c | 1614 | #ifdef CONFIG_POSIX_TIMERS |
f06febc9 FM |
1615 | /* |
1616 | * Initialize POSIX timer handling for a single task. | |
1617 | */ | |
1618 | static void posix_cpu_timers_init(struct task_struct *tsk) | |
1619 | { | |
64861634 MS |
1620 | tsk->cputime_expires.prof_exp = 0; |
1621 | tsk->cputime_expires.virt_exp = 0; | |
f06febc9 FM |
1622 | tsk->cputime_expires.sched_exp = 0; |
1623 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); | |
1624 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); | |
1625 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); | |
1626 | } | |
b18b6a9c NP |
1627 | #else |
1628 | static inline void posix_cpu_timers_init(struct task_struct *tsk) { } | |
1629 | #endif | |
f06febc9 | 1630 | |
2c470475 EB |
1631 | static inline void init_task_pid_links(struct task_struct *task) |
1632 | { | |
1633 | enum pid_type type; | |
1634 | ||
1635 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
1636 | INIT_HLIST_NODE(&task->pid_links[type]); | |
1637 | } | |
1638 | } | |
1639 | ||
81907739 ON |
1640 | static inline void |
1641 | init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid) | |
1642 | { | |
2c470475 EB |
1643 | if (type == PIDTYPE_PID) |
1644 | task->thread_pid = pid; | |
1645 | else | |
1646 | task->signal->pids[type] = pid; | |
81907739 ON |
1647 | } |
1648 | ||
6bfbaa51 IM |
1649 | static inline void rcu_copy_process(struct task_struct *p) |
1650 | { | |
1651 | #ifdef CONFIG_PREEMPT_RCU | |
1652 | p->rcu_read_lock_nesting = 0; | |
1653 | p->rcu_read_unlock_special.s = 0; | |
1654 | p->rcu_blocked_node = NULL; | |
1655 | INIT_LIST_HEAD(&p->rcu_node_entry); | |
1656 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1657 | #ifdef CONFIG_TASKS_RCU | |
1658 | p->rcu_tasks_holdout = false; | |
1659 | INIT_LIST_HEAD(&p->rcu_tasks_holdout_list); | |
1660 | p->rcu_tasks_idle_cpu = -1; | |
1661 | #endif /* #ifdef CONFIG_TASKS_RCU */ | |
1662 | } | |
1663 | ||
1da177e4 LT |
1664 | /* |
1665 | * This creates a new process as a copy of the old one, | |
1666 | * but does not actually start it yet. | |
1667 | * | |
1668 | * It copies the registers, and all the appropriate | |
1669 | * parts of the process environment (as per the clone | |
1670 | * flags). The actual kick-off is left to the caller. | |
1671 | */ | |
0766f788 ER |
1672 | static __latent_entropy struct task_struct *copy_process( |
1673 | unsigned long clone_flags, | |
36c8b586 | 1674 | unsigned long stack_start, |
36c8b586 | 1675 | unsigned long stack_size, |
36c8b586 | 1676 | int __user *child_tidptr, |
09a05394 | 1677 | struct pid *pid, |
3033f14a | 1678 | int trace, |
725fc629 AK |
1679 | unsigned long tls, |
1680 | int node) | |
1da177e4 LT |
1681 | { |
1682 | int retval; | |
a24efe62 | 1683 | struct task_struct *p; |
c3ad2c3b | 1684 | struct multiprocess_signals delayed; |
1da177e4 | 1685 | |
667b6094 MPS |
1686 | /* |
1687 | * Don't allow sharing the root directory with processes in a different | |
1688 | * namespace | |
1689 | */ | |
1da177e4 LT |
1690 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) |
1691 | return ERR_PTR(-EINVAL); | |
1692 | ||
e66eded8 EB |
1693 | if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) |
1694 | return ERR_PTR(-EINVAL); | |
1695 | ||
1da177e4 LT |
1696 | /* |
1697 | * Thread groups must share signals as well, and detached threads | |
1698 | * can only be started up within the thread group. | |
1699 | */ | |
1700 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
1701 | return ERR_PTR(-EINVAL); | |
1702 | ||
1703 | /* | |
1704 | * Shared signal handlers imply shared VM. By way of the above, | |
1705 | * thread groups also imply shared VM. Blocking this case allows | |
1706 | * for various simplifications in other code. | |
1707 | */ | |
1708 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
1709 | return ERR_PTR(-EINVAL); | |
1710 | ||
123be07b SB |
1711 | /* |
1712 | * Siblings of global init remain as zombies on exit since they are | |
1713 | * not reaped by their parent (swapper). To solve this and to avoid | |
1714 | * multi-rooted process trees, prevent global and container-inits | |
1715 | * from creating siblings. | |
1716 | */ | |
1717 | if ((clone_flags & CLONE_PARENT) && | |
1718 | current->signal->flags & SIGNAL_UNKILLABLE) | |
1719 | return ERR_PTR(-EINVAL); | |
1720 | ||
8382fcac | 1721 | /* |
40a0d32d | 1722 | * If the new process will be in a different pid or user namespace |
faf00da5 | 1723 | * do not allow it to share a thread group with the forking task. |
8382fcac | 1724 | */ |
faf00da5 | 1725 | if (clone_flags & CLONE_THREAD) { |
40a0d32d ON |
1726 | if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || |
1727 | (task_active_pid_ns(current) != | |
1728 | current->nsproxy->pid_ns_for_children)) | |
1729 | return ERR_PTR(-EINVAL); | |
1730 | } | |
8382fcac | 1731 | |
c3ad2c3b EB |
1732 | /* |
1733 | * Force any signals received before this point to be delivered | |
1734 | * before the fork happens. Collect up signals sent to multiple | |
1735 | * processes that happen during the fork and delay them so that | |
1736 | * they appear to happen after the fork. | |
1737 | */ | |
1738 | sigemptyset(&delayed.signal); | |
1739 | INIT_HLIST_NODE(&delayed.node); | |
1740 | ||
1741 | spin_lock_irq(¤t->sighand->siglock); | |
1742 | if (!(clone_flags & CLONE_THREAD)) | |
1743 | hlist_add_head(&delayed.node, ¤t->signal->multiprocess); | |
1744 | recalc_sigpending(); | |
1745 | spin_unlock_irq(¤t->sighand->siglock); | |
1746 | retval = -ERESTARTNOINTR; | |
1747 | if (signal_pending(current)) | |
1748 | goto fork_out; | |
1749 | ||
1da177e4 | 1750 | retval = -ENOMEM; |
725fc629 | 1751 | p = dup_task_struct(current, node); |
1da177e4 LT |
1752 | if (!p) |
1753 | goto fork_out; | |
1754 | ||
4d6501dc VN |
1755 | /* |
1756 | * This _must_ happen before we call free_task(), i.e. before we jump | |
1757 | * to any of the bad_fork_* labels. This is to avoid freeing | |
1758 | * p->set_child_tid which is (ab)used as a kthread's data pointer for | |
1759 | * kernel threads (PF_KTHREAD). | |
1760 | */ | |
1761 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; | |
1762 | /* | |
1763 | * Clear TID on mm_release()? | |
1764 | */ | |
1765 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL; | |
1766 | ||
f7e8b616 SR |
1767 | ftrace_graph_init_task(p); |
1768 | ||
bea493a0 PZ |
1769 | rt_mutex_init_task(p); |
1770 | ||
d12c1a37 | 1771 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
1772 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
1773 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
1774 | #endif | |
1da177e4 | 1775 | retval = -EAGAIN; |
3b11a1de | 1776 | if (atomic_read(&p->real_cred->user->processes) >= |
78d7d407 | 1777 | task_rlimit(p, RLIMIT_NPROC)) { |
b57922b6 EP |
1778 | if (p->real_cred->user != INIT_USER && |
1779 | !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) | |
1da177e4 LT |
1780 | goto bad_fork_free; |
1781 | } | |
72fa5997 | 1782 | current->flags &= ~PF_NPROC_EXCEEDED; |
1da177e4 | 1783 | |
f1752eec DH |
1784 | retval = copy_creds(p, clone_flags); |
1785 | if (retval < 0) | |
1786 | goto bad_fork_free; | |
1da177e4 LT |
1787 | |
1788 | /* | |
1789 | * If multiple threads are within copy_process(), then this check | |
1790 | * triggers too late. This doesn't hurt, the check is only there | |
1791 | * to stop root fork bombs. | |
1792 | */ | |
04ec93fe | 1793 | retval = -EAGAIN; |
1da177e4 LT |
1794 | if (nr_threads >= max_threads) |
1795 | goto bad_fork_cleanup_count; | |
1796 | ||
ca74e92b | 1797 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
c1de45ca | 1798 | p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE); |
514ddb44 | 1799 | p->flags |= PF_FORKNOEXEC; |
1da177e4 LT |
1800 | INIT_LIST_HEAD(&p->children); |
1801 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 1802 | rcu_copy_process(p); |
1da177e4 LT |
1803 | p->vfork_done = NULL; |
1804 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 1805 | |
1da177e4 LT |
1806 | init_sigpending(&p->pending); |
1807 | ||
64861634 | 1808 | p->utime = p->stime = p->gtime = 0; |
40565b5a | 1809 | #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME |
64861634 | 1810 | p->utimescaled = p->stimescaled = 0; |
40565b5a | 1811 | #endif |
9d7fb042 PZ |
1812 | prev_cputime_init(&p->prev_cputime); |
1813 | ||
6a61671b | 1814 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN |
bac5b6b6 FW |
1815 | seqcount_init(&p->vtime.seqcount); |
1816 | p->vtime.starttime = 0; | |
1817 | p->vtime.state = VTIME_INACTIVE; | |
6a61671b FW |
1818 | #endif |
1819 | ||
a3a2e76c KH |
1820 | #if defined(SPLIT_RSS_COUNTING) |
1821 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
1822 | #endif | |
172ba844 | 1823 | |
6976675d AV |
1824 | p->default_timer_slack_ns = current->timer_slack_ns; |
1825 | ||
eb414681 JW |
1826 | #ifdef CONFIG_PSI |
1827 | p->psi_flags = 0; | |
1828 | #endif | |
1829 | ||
5995477a | 1830 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
1831 | acct_clear_integrals(p); |
1832 | ||
f06febc9 | 1833 | posix_cpu_timers_init(p); |
1da177e4 | 1834 | |
ccbf62d8 | 1835 | p->start_time = ktime_get_ns(); |
57e0be04 | 1836 | p->real_start_time = ktime_get_boot_ns(); |
1da177e4 | 1837 | p->io_context = NULL; |
c0b0ae8a | 1838 | audit_set_context(p, NULL); |
b4f48b63 | 1839 | cgroup_fork(p); |
1da177e4 | 1840 | #ifdef CONFIG_NUMA |
846a16bf | 1841 | p->mempolicy = mpol_dup(p->mempolicy); |
fb0a685c DRO |
1842 | if (IS_ERR(p->mempolicy)) { |
1843 | retval = PTR_ERR(p->mempolicy); | |
1844 | p->mempolicy = NULL; | |
e8604cb4 | 1845 | goto bad_fork_cleanup_threadgroup_lock; |
fb0a685c | 1846 | } |
1da177e4 | 1847 | #endif |
778d3b0f MH |
1848 | #ifdef CONFIG_CPUSETS |
1849 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE; | |
1850 | p->cpuset_slab_spread_rotor = NUMA_NO_NODE; | |
cc9a6c87 | 1851 | seqcount_init(&p->mems_allowed_seq); |
778d3b0f | 1852 | #endif |
de30a2b3 IM |
1853 | #ifdef CONFIG_TRACE_IRQFLAGS |
1854 | p->irq_events = 0; | |
1855 | p->hardirqs_enabled = 0; | |
1856 | p->hardirq_enable_ip = 0; | |
1857 | p->hardirq_enable_event = 0; | |
1858 | p->hardirq_disable_ip = _THIS_IP_; | |
1859 | p->hardirq_disable_event = 0; | |
1860 | p->softirqs_enabled = 1; | |
1861 | p->softirq_enable_ip = _THIS_IP_; | |
1862 | p->softirq_enable_event = 0; | |
1863 | p->softirq_disable_ip = 0; | |
1864 | p->softirq_disable_event = 0; | |
1865 | p->hardirq_context = 0; | |
1866 | p->softirq_context = 0; | |
1867 | #endif | |
8bcbde54 DH |
1868 | |
1869 | p->pagefault_disabled = 0; | |
1870 | ||
fbb9ce95 IM |
1871 | #ifdef CONFIG_LOCKDEP |
1872 | p->lockdep_depth = 0; /* no locks held yet */ | |
1873 | p->curr_chain_key = 0; | |
1874 | p->lockdep_recursion = 0; | |
b09be676 | 1875 | lockdep_init_task(p); |
fbb9ce95 | 1876 | #endif |
1da177e4 | 1877 | |
408894ee IM |
1878 | #ifdef CONFIG_DEBUG_MUTEXES |
1879 | p->blocked_on = NULL; /* not blocked yet */ | |
1880 | #endif | |
cafe5635 KO |
1881 | #ifdef CONFIG_BCACHE |
1882 | p->sequential_io = 0; | |
1883 | p->sequential_io_avg = 0; | |
1884 | #endif | |
0f481406 | 1885 | |
3c90e6e9 | 1886 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
aab03e05 DF |
1887 | retval = sched_fork(clone_flags, p); |
1888 | if (retval) | |
1889 | goto bad_fork_cleanup_policy; | |
6ab423e0 | 1890 | |
cdd6c482 | 1891 | retval = perf_event_init_task(p); |
6ab423e0 PZ |
1892 | if (retval) |
1893 | goto bad_fork_cleanup_policy; | |
fb0a685c DRO |
1894 | retval = audit_alloc(p); |
1895 | if (retval) | |
6c72e350 | 1896 | goto bad_fork_cleanup_perf; |
1da177e4 | 1897 | /* copy all the process information */ |
ab602f79 | 1898 | shm_init_task(p); |
e4e55b47 | 1899 | retval = security_task_alloc(p, clone_flags); |
fb0a685c | 1900 | if (retval) |
1da177e4 | 1901 | goto bad_fork_cleanup_audit; |
e4e55b47 TH |
1902 | retval = copy_semundo(clone_flags, p); |
1903 | if (retval) | |
1904 | goto bad_fork_cleanup_security; | |
fb0a685c DRO |
1905 | retval = copy_files(clone_flags, p); |
1906 | if (retval) | |
1da177e4 | 1907 | goto bad_fork_cleanup_semundo; |
fb0a685c DRO |
1908 | retval = copy_fs(clone_flags, p); |
1909 | if (retval) | |
1da177e4 | 1910 | goto bad_fork_cleanup_files; |
fb0a685c DRO |
1911 | retval = copy_sighand(clone_flags, p); |
1912 | if (retval) | |
1da177e4 | 1913 | goto bad_fork_cleanup_fs; |
fb0a685c DRO |
1914 | retval = copy_signal(clone_flags, p); |
1915 | if (retval) | |
1da177e4 | 1916 | goto bad_fork_cleanup_sighand; |
fb0a685c DRO |
1917 | retval = copy_mm(clone_flags, p); |
1918 | if (retval) | |
1da177e4 | 1919 | goto bad_fork_cleanup_signal; |
fb0a685c DRO |
1920 | retval = copy_namespaces(clone_flags, p); |
1921 | if (retval) | |
d84f4f99 | 1922 | goto bad_fork_cleanup_mm; |
fb0a685c DRO |
1923 | retval = copy_io(clone_flags, p); |
1924 | if (retval) | |
fd0928df | 1925 | goto bad_fork_cleanup_namespaces; |
3033f14a | 1926 | retval = copy_thread_tls(clone_flags, stack_start, stack_size, p, tls); |
1da177e4 | 1927 | if (retval) |
fd0928df | 1928 | goto bad_fork_cleanup_io; |
1da177e4 | 1929 | |
afaef01c AP |
1930 | stackleak_task_init(p); |
1931 | ||
425fb2b4 | 1932 | if (pid != &init_struct_pid) { |
c2b1df2e | 1933 | pid = alloc_pid(p->nsproxy->pid_ns_for_children); |
35f71bc0 MH |
1934 | if (IS_ERR(pid)) { |
1935 | retval = PTR_ERR(pid); | |
0740aa5f | 1936 | goto bad_fork_cleanup_thread; |
35f71bc0 | 1937 | } |
425fb2b4 PE |
1938 | } |
1939 | ||
73c10101 JA |
1940 | #ifdef CONFIG_BLOCK |
1941 | p->plug = NULL; | |
1942 | #endif | |
42b2dd0a | 1943 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1944 | p->robust_list = NULL; |
1945 | #ifdef CONFIG_COMPAT | |
1946 | p->compat_robust_list = NULL; | |
1947 | #endif | |
c87e2837 IM |
1948 | INIT_LIST_HEAD(&p->pi_state_list); |
1949 | p->pi_state_cache = NULL; | |
42b2dd0a | 1950 | #endif |
f9a3879a GM |
1951 | /* |
1952 | * sigaltstack should be cleared when sharing the same VM | |
1953 | */ | |
1954 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
2a742138 | 1955 | sas_ss_reset(p); |
f9a3879a | 1956 | |
1da177e4 | 1957 | /* |
6580807d ON |
1958 | * Syscall tracing and stepping should be turned off in the |
1959 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 1960 | */ |
6580807d | 1961 | user_disable_single_step(p); |
1da177e4 | 1962 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); |
ed75e8d5 LV |
1963 | #ifdef TIF_SYSCALL_EMU |
1964 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1965 | #endif | |
9745512c | 1966 | clear_all_latency_tracing(p); |
1da177e4 | 1967 | |
1da177e4 | 1968 | /* ok, now we should be set up.. */ |
18c830df ON |
1969 | p->pid = pid_nr(pid); |
1970 | if (clone_flags & CLONE_THREAD) { | |
5f8aadd8 | 1971 | p->exit_signal = -1; |
18c830df ON |
1972 | p->group_leader = current->group_leader; |
1973 | p->tgid = current->tgid; | |
1974 | } else { | |
1975 | if (clone_flags & CLONE_PARENT) | |
1976 | p->exit_signal = current->group_leader->exit_signal; | |
1977 | else | |
1978 | p->exit_signal = (clone_flags & CSIGNAL); | |
1979 | p->group_leader = p; | |
1980 | p->tgid = p->pid; | |
1981 | } | |
5f8aadd8 | 1982 | |
9d823e8f WF |
1983 | p->nr_dirtied = 0; |
1984 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10); | |
83712358 | 1985 | p->dirty_paused_when = 0; |
9d823e8f | 1986 | |
bb8cbbfe | 1987 | p->pdeath_signal = 0; |
47e65328 | 1988 | INIT_LIST_HEAD(&p->thread_group); |
158e1645 | 1989 | p->task_works = NULL; |
1da177e4 | 1990 | |
780de9dd | 1991 | cgroup_threadgroup_change_begin(current); |
7e47682e AS |
1992 | /* |
1993 | * Ensure that the cgroup subsystem policies allow the new process to be | |
1994 | * forked. It should be noted the the new process's css_set can be changed | |
1995 | * between here and cgroup_post_fork() if an organisation operation is in | |
1996 | * progress. | |
1997 | */ | |
b53202e6 | 1998 | retval = cgroup_can_fork(p); |
7e47682e AS |
1999 | if (retval) |
2000 | goto bad_fork_free_pid; | |
2001 | ||
18c830df ON |
2002 | /* |
2003 | * Make it visible to the rest of the system, but dont wake it up yet. | |
2004 | * Need tasklist lock for parent etc handling! | |
2005 | */ | |
1da177e4 LT |
2006 | write_lock_irq(&tasklist_lock); |
2007 | ||
1da177e4 | 2008 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 2009 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 2010 | p->real_parent = current->real_parent; |
2d5516cb ON |
2011 | p->parent_exec_id = current->parent_exec_id; |
2012 | } else { | |
1da177e4 | 2013 | p->real_parent = current; |
2d5516cb ON |
2014 | p->parent_exec_id = current->self_exec_id; |
2015 | } | |
1da177e4 | 2016 | |
d83a7cb3 JP |
2017 | klp_copy_process(p); |
2018 | ||
3f17da69 | 2019 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 | 2020 | |
dbd95212 KC |
2021 | /* |
2022 | * Copy seccomp details explicitly here, in case they were changed | |
2023 | * before holding sighand lock. | |
2024 | */ | |
2025 | copy_seccomp(p); | |
2026 | ||
d7822b1e MD |
2027 | rseq_fork(p, clone_flags); |
2028 | ||
4ca1d3ee | 2029 | /* Don't start children in a dying pid namespace */ |
e8cfbc24 | 2030 | if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) { |
3fd37226 KT |
2031 | retval = -ENOMEM; |
2032 | goto bad_fork_cancel_cgroup; | |
2033 | } | |
4a2c7a78 | 2034 | |
7673bf55 EB |
2035 | /* Let kill terminate clone/fork in the middle */ |
2036 | if (fatal_signal_pending(current)) { | |
2037 | retval = -EINTR; | |
2038 | goto bad_fork_cancel_cgroup; | |
2039 | } | |
2040 | ||
4a2c7a78 | 2041 | |
2c470475 | 2042 | init_task_pid_links(p); |
73b9ebfe | 2043 | if (likely(p->pid)) { |
4b9d33e6 | 2044 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); |
73b9ebfe | 2045 | |
81907739 | 2046 | init_task_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 2047 | if (thread_group_leader(p)) { |
6883f81a | 2048 | init_task_pid(p, PIDTYPE_TGID, pid); |
81907739 ON |
2049 | init_task_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
2050 | init_task_pid(p, PIDTYPE_SID, task_session(current)); | |
2051 | ||
1c4042c2 | 2052 | if (is_child_reaper(pid)) { |
17cf22c3 | 2053 | ns_of_pid(pid)->child_reaper = p; |
1c4042c2 EB |
2054 | p->signal->flags |= SIGNAL_UNKILLABLE; |
2055 | } | |
c3ad2c3b | 2056 | p->signal->shared_pending.signal = delayed.signal; |
9c9f4ded | 2057 | p->signal->tty = tty_kref_get(current->signal->tty); |
749860ce PT |
2058 | /* |
2059 | * Inherit has_child_subreaper flag under the same | |
2060 | * tasklist_lock with adding child to the process tree | |
2061 | * for propagate_has_child_subreaper optimization. | |
2062 | */ | |
2063 | p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper || | |
2064 | p->real_parent->signal->is_child_subreaper; | |
9cd80bbb | 2065 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 2066 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
6883f81a | 2067 | attach_pid(p, PIDTYPE_TGID); |
81907739 ON |
2068 | attach_pid(p, PIDTYPE_PGID); |
2069 | attach_pid(p, PIDTYPE_SID); | |
909ea964 | 2070 | __this_cpu_inc(process_counts); |
80628ca0 ON |
2071 | } else { |
2072 | current->signal->nr_threads++; | |
2073 | atomic_inc(¤t->signal->live); | |
2074 | atomic_inc(¤t->signal->sigcnt); | |
924de3b8 | 2075 | task_join_group_stop(p); |
80628ca0 ON |
2076 | list_add_tail_rcu(&p->thread_group, |
2077 | &p->group_leader->thread_group); | |
0c740d0a ON |
2078 | list_add_tail_rcu(&p->thread_node, |
2079 | &p->signal->thread_head); | |
73b9ebfe | 2080 | } |
81907739 | 2081 | attach_pid(p, PIDTYPE_PID); |
73b9ebfe | 2082 | nr_threads++; |
1da177e4 | 2083 | } |
1da177e4 | 2084 | total_forks++; |
c3ad2c3b | 2085 | hlist_del_init(&delayed.node); |
3f17da69 | 2086 | spin_unlock(¤t->sighand->siglock); |
4af4206b | 2087 | syscall_tracepoint_update(p); |
1da177e4 | 2088 | write_unlock_irq(&tasklist_lock); |
4af4206b | 2089 | |
c13cf856 | 2090 | proc_fork_connector(p); |
b53202e6 | 2091 | cgroup_post_fork(p); |
780de9dd | 2092 | cgroup_threadgroup_change_end(current); |
cdd6c482 | 2093 | perf_event_fork(p); |
43d2b113 KH |
2094 | |
2095 | trace_task_newtask(p, clone_flags); | |
3ab67966 | 2096 | uprobe_copy_process(p, clone_flags); |
43d2b113 | 2097 | |
1da177e4 LT |
2098 | return p; |
2099 | ||
7e47682e | 2100 | bad_fork_cancel_cgroup: |
3fd37226 KT |
2101 | spin_unlock(¤t->sighand->siglock); |
2102 | write_unlock_irq(&tasklist_lock); | |
b53202e6 | 2103 | cgroup_cancel_fork(p); |
425fb2b4 | 2104 | bad_fork_free_pid: |
780de9dd | 2105 | cgroup_threadgroup_change_end(current); |
425fb2b4 PE |
2106 | if (pid != &init_struct_pid) |
2107 | free_pid(pid); | |
0740aa5f JS |
2108 | bad_fork_cleanup_thread: |
2109 | exit_thread(p); | |
fd0928df | 2110 | bad_fork_cleanup_io: |
b69f2292 LR |
2111 | if (p->io_context) |
2112 | exit_io_context(p); | |
ab516013 | 2113 | bad_fork_cleanup_namespaces: |
444f378b | 2114 | exit_task_namespaces(p); |
1da177e4 | 2115 | bad_fork_cleanup_mm: |
c9f01245 | 2116 | if (p->mm) |
1da177e4 LT |
2117 | mmput(p->mm); |
2118 | bad_fork_cleanup_signal: | |
4ab6c083 | 2119 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 2120 | free_signal_struct(p->signal); |
1da177e4 | 2121 | bad_fork_cleanup_sighand: |
a7e5328a | 2122 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
2123 | bad_fork_cleanup_fs: |
2124 | exit_fs(p); /* blocking */ | |
2125 | bad_fork_cleanup_files: | |
2126 | exit_files(p); /* blocking */ | |
2127 | bad_fork_cleanup_semundo: | |
2128 | exit_sem(p); | |
e4e55b47 TH |
2129 | bad_fork_cleanup_security: |
2130 | security_task_free(p); | |
1da177e4 LT |
2131 | bad_fork_cleanup_audit: |
2132 | audit_free(p); | |
6c72e350 | 2133 | bad_fork_cleanup_perf: |
cdd6c482 | 2134 | perf_event_free_task(p); |
6c72e350 | 2135 | bad_fork_cleanup_policy: |
b09be676 | 2136 | lockdep_free_task(p); |
1da177e4 | 2137 | #ifdef CONFIG_NUMA |
f0be3d32 | 2138 | mpol_put(p->mempolicy); |
e8604cb4 | 2139 | bad_fork_cleanup_threadgroup_lock: |
1da177e4 | 2140 | #endif |
35df17c5 | 2141 | delayacct_tsk_free(p); |
1da177e4 | 2142 | bad_fork_cleanup_count: |
d84f4f99 | 2143 | atomic_dec(&p->cred->user->processes); |
e0e81739 | 2144 | exit_creds(p); |
1da177e4 | 2145 | bad_fork_free: |
405c0759 | 2146 | p->state = TASK_DEAD; |
68f24b08 | 2147 | put_task_stack(p); |
1da177e4 | 2148 | free_task(p); |
fe7d37d1 | 2149 | fork_out: |
c3ad2c3b EB |
2150 | spin_lock_irq(¤t->sighand->siglock); |
2151 | hlist_del_init(&delayed.node); | |
2152 | spin_unlock_irq(¤t->sighand->siglock); | |
fe7d37d1 | 2153 | return ERR_PTR(retval); |
1da177e4 LT |
2154 | } |
2155 | ||
2c470475 | 2156 | static inline void init_idle_pids(struct task_struct *idle) |
f106eee1 ON |
2157 | { |
2158 | enum pid_type type; | |
2159 | ||
2160 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
2c470475 EB |
2161 | INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */ |
2162 | init_task_pid(idle, type, &init_struct_pid); | |
f106eee1 ON |
2163 | } |
2164 | } | |
2165 | ||
0db0628d | 2166 | struct task_struct *fork_idle(int cpu) |
1da177e4 | 2167 | { |
36c8b586 | 2168 | struct task_struct *task; |
725fc629 AK |
2169 | task = copy_process(CLONE_VM, 0, 0, NULL, &init_struct_pid, 0, 0, |
2170 | cpu_to_node(cpu)); | |
f106eee1 | 2171 | if (!IS_ERR(task)) { |
2c470475 | 2172 | init_idle_pids(task); |
753ca4f3 | 2173 | init_idle(task, cpu); |
f106eee1 | 2174 | } |
73b9ebfe | 2175 | |
1da177e4 LT |
2176 | return task; |
2177 | } | |
2178 | ||
1da177e4 LT |
2179 | /* |
2180 | * Ok, this is the main fork-routine. | |
2181 | * | |
2182 | * It copies the process, and if successful kick-starts | |
2183 | * it and waits for it to finish using the VM if required. | |
2184 | */ | |
3033f14a | 2185 | long _do_fork(unsigned long clone_flags, |
1da177e4 | 2186 | unsigned long stack_start, |
1da177e4 LT |
2187 | unsigned long stack_size, |
2188 | int __user *parent_tidptr, | |
3033f14a JT |
2189 | int __user *child_tidptr, |
2190 | unsigned long tls) | |
1da177e4 | 2191 | { |
9f5325aa MPS |
2192 | struct completion vfork; |
2193 | struct pid *pid; | |
1da177e4 LT |
2194 | struct task_struct *p; |
2195 | int trace = 0; | |
92476d7f | 2196 | long nr; |
1da177e4 | 2197 | |
09a05394 | 2198 | /* |
4b9d33e6 TH |
2199 | * Determine whether and which event to report to ptracer. When |
2200 | * called from kernel_thread or CLONE_UNTRACED is explicitly | |
2201 | * requested, no event is reported; otherwise, report if the event | |
2202 | * for the type of forking is enabled. | |
09a05394 | 2203 | */ |
e80d6661 | 2204 | if (!(clone_flags & CLONE_UNTRACED)) { |
4b9d33e6 TH |
2205 | if (clone_flags & CLONE_VFORK) |
2206 | trace = PTRACE_EVENT_VFORK; | |
2207 | else if ((clone_flags & CSIGNAL) != SIGCHLD) | |
2208 | trace = PTRACE_EVENT_CLONE; | |
2209 | else | |
2210 | trace = PTRACE_EVENT_FORK; | |
2211 | ||
2212 | if (likely(!ptrace_event_enabled(current, trace))) | |
2213 | trace = 0; | |
2214 | } | |
1da177e4 | 2215 | |
62e791c1 | 2216 | p = copy_process(clone_flags, stack_start, stack_size, |
725fc629 | 2217 | child_tidptr, NULL, trace, tls, NUMA_NO_NODE); |
38addce8 | 2218 | add_latent_entropy(); |
9f5325aa MPS |
2219 | |
2220 | if (IS_ERR(p)) | |
2221 | return PTR_ERR(p); | |
2222 | ||
1da177e4 LT |
2223 | /* |
2224 | * Do this prior waking up the new thread - the thread pointer | |
2225 | * might get invalid after that point, if the thread exits quickly. | |
2226 | */ | |
9f5325aa | 2227 | trace_sched_process_fork(current, p); |
0a16b607 | 2228 | |
9f5325aa MPS |
2229 | pid = get_task_pid(p, PIDTYPE_PID); |
2230 | nr = pid_vnr(pid); | |
30e49c26 | 2231 | |
9f5325aa MPS |
2232 | if (clone_flags & CLONE_PARENT_SETTID) |
2233 | put_user(nr, parent_tidptr); | |
a6f5e063 | 2234 | |
9f5325aa MPS |
2235 | if (clone_flags & CLONE_VFORK) { |
2236 | p->vfork_done = &vfork; | |
2237 | init_completion(&vfork); | |
2238 | get_task_struct(p); | |
2239 | } | |
1da177e4 | 2240 | |
9f5325aa | 2241 | wake_up_new_task(p); |
09a05394 | 2242 | |
9f5325aa MPS |
2243 | /* forking complete and child started to run, tell ptracer */ |
2244 | if (unlikely(trace)) | |
2245 | ptrace_event_pid(trace, pid); | |
4e52365f | 2246 | |
9f5325aa MPS |
2247 | if (clone_flags & CLONE_VFORK) { |
2248 | if (!wait_for_vfork_done(p, &vfork)) | |
2249 | ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); | |
1da177e4 | 2250 | } |
9f5325aa MPS |
2251 | |
2252 | put_pid(pid); | |
92476d7f | 2253 | return nr; |
1da177e4 LT |
2254 | } |
2255 | ||
3033f14a JT |
2256 | #ifndef CONFIG_HAVE_COPY_THREAD_TLS |
2257 | /* For compatibility with architectures that call do_fork directly rather than | |
2258 | * using the syscall entry points below. */ | |
2259 | long do_fork(unsigned long clone_flags, | |
2260 | unsigned long stack_start, | |
2261 | unsigned long stack_size, | |
2262 | int __user *parent_tidptr, | |
2263 | int __user *child_tidptr) | |
2264 | { | |
2265 | return _do_fork(clone_flags, stack_start, stack_size, | |
2266 | parent_tidptr, child_tidptr, 0); | |
2267 | } | |
2268 | #endif | |
2269 | ||
2aa3a7f8 AV |
2270 | /* |
2271 | * Create a kernel thread. | |
2272 | */ | |
2273 | pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
2274 | { | |
3033f14a JT |
2275 | return _do_fork(flags|CLONE_VM|CLONE_UNTRACED, (unsigned long)fn, |
2276 | (unsigned long)arg, NULL, NULL, 0); | |
2aa3a7f8 | 2277 | } |
2aa3a7f8 | 2278 | |
d2125043 AV |
2279 | #ifdef __ARCH_WANT_SYS_FORK |
2280 | SYSCALL_DEFINE0(fork) | |
2281 | { | |
2282 | #ifdef CONFIG_MMU | |
3033f14a | 2283 | return _do_fork(SIGCHLD, 0, 0, NULL, NULL, 0); |
d2125043 AV |
2284 | #else |
2285 | /* can not support in nommu mode */ | |
5d59e182 | 2286 | return -EINVAL; |
d2125043 AV |
2287 | #endif |
2288 | } | |
2289 | #endif | |
2290 | ||
2291 | #ifdef __ARCH_WANT_SYS_VFORK | |
2292 | SYSCALL_DEFINE0(vfork) | |
2293 | { | |
3033f14a JT |
2294 | return _do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0, |
2295 | 0, NULL, NULL, 0); | |
d2125043 AV |
2296 | } |
2297 | #endif | |
2298 | ||
2299 | #ifdef __ARCH_WANT_SYS_CLONE | |
2300 | #ifdef CONFIG_CLONE_BACKWARDS | |
2301 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2302 | int __user *, parent_tidptr, | |
3033f14a | 2303 | unsigned long, tls, |
d2125043 AV |
2304 | int __user *, child_tidptr) |
2305 | #elif defined(CONFIG_CLONE_BACKWARDS2) | |
2306 | SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags, | |
2307 | int __user *, parent_tidptr, | |
2308 | int __user *, child_tidptr, | |
3033f14a | 2309 | unsigned long, tls) |
dfa9771a MS |
2310 | #elif defined(CONFIG_CLONE_BACKWARDS3) |
2311 | SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2312 | int, stack_size, | |
2313 | int __user *, parent_tidptr, | |
2314 | int __user *, child_tidptr, | |
3033f14a | 2315 | unsigned long, tls) |
d2125043 AV |
2316 | #else |
2317 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2318 | int __user *, parent_tidptr, | |
2319 | int __user *, child_tidptr, | |
3033f14a | 2320 | unsigned long, tls) |
d2125043 AV |
2321 | #endif |
2322 | { | |
3033f14a | 2323 | return _do_fork(clone_flags, newsp, 0, parent_tidptr, child_tidptr, tls); |
d2125043 AV |
2324 | } |
2325 | #endif | |
2326 | ||
0f1b92cb ON |
2327 | void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data) |
2328 | { | |
2329 | struct task_struct *leader, *parent, *child; | |
2330 | int res; | |
2331 | ||
2332 | read_lock(&tasklist_lock); | |
2333 | leader = top = top->group_leader; | |
2334 | down: | |
2335 | for_each_thread(leader, parent) { | |
2336 | list_for_each_entry(child, &parent->children, sibling) { | |
2337 | res = visitor(child, data); | |
2338 | if (res) { | |
2339 | if (res < 0) | |
2340 | goto out; | |
2341 | leader = child; | |
2342 | goto down; | |
2343 | } | |
2344 | up: | |
2345 | ; | |
2346 | } | |
2347 | } | |
2348 | ||
2349 | if (leader != top) { | |
2350 | child = leader; | |
2351 | parent = child->real_parent; | |
2352 | leader = parent->group_leader; | |
2353 | goto up; | |
2354 | } | |
2355 | out: | |
2356 | read_unlock(&tasklist_lock); | |
2357 | } | |
2358 | ||
5fd63b30 RT |
2359 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
2360 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
2361 | #endif | |
2362 | ||
51cc5068 | 2363 | static void sighand_ctor(void *data) |
aa1757f9 ON |
2364 | { |
2365 | struct sighand_struct *sighand = data; | |
2366 | ||
a35afb83 | 2367 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 2368 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
2369 | } |
2370 | ||
1da177e4 LT |
2371 | void __init proc_caches_init(void) |
2372 | { | |
c1a2f7f0 RR |
2373 | unsigned int mm_size; |
2374 | ||
1da177e4 LT |
2375 | sighand_cachep = kmem_cache_create("sighand_cache", |
2376 | sizeof(struct sighand_struct), 0, | |
5f0d5a3a | 2377 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU| |
75f296d9 | 2378 | SLAB_ACCOUNT, sighand_ctor); |
1da177e4 LT |
2379 | signal_cachep = kmem_cache_create("signal_cache", |
2380 | sizeof(struct signal_struct), 0, | |
75f296d9 | 2381 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2382 | NULL); |
20c2df83 | 2383 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 2384 | sizeof(struct files_struct), 0, |
75f296d9 | 2385 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2386 | NULL); |
20c2df83 | 2387 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 2388 | sizeof(struct fs_struct), 0, |
75f296d9 | 2389 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2390 | NULL); |
c1a2f7f0 | 2391 | |
6345d24d | 2392 | /* |
c1a2f7f0 RR |
2393 | * The mm_cpumask is located at the end of mm_struct, and is |
2394 | * dynamically sized based on the maximum CPU number this system | |
2395 | * can have, taking hotplug into account (nr_cpu_ids). | |
6345d24d | 2396 | */ |
c1a2f7f0 RR |
2397 | mm_size = sizeof(struct mm_struct) + cpumask_size(); |
2398 | ||
07dcd7fe | 2399 | mm_cachep = kmem_cache_create_usercopy("mm_struct", |
c1a2f7f0 | 2400 | mm_size, ARCH_MIN_MMSTRUCT_ALIGN, |
75f296d9 | 2401 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
07dcd7fe DW |
2402 | offsetof(struct mm_struct, saved_auxv), |
2403 | sizeof_field(struct mm_struct, saved_auxv), | |
5d097056 VD |
2404 | NULL); |
2405 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT); | |
8feae131 | 2406 | mmap_init(); |
66577193 | 2407 | nsproxy_cache_init(); |
1da177e4 | 2408 | } |
cf2e340f | 2409 | |
cf2e340f | 2410 | /* |
9bfb23fc | 2411 | * Check constraints on flags passed to the unshare system call. |
cf2e340f | 2412 | */ |
9bfb23fc | 2413 | static int check_unshare_flags(unsigned long unshare_flags) |
cf2e340f | 2414 | { |
9bfb23fc ON |
2415 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
2416 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| | |
50804fe3 | 2417 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET| |
a79a908f | 2418 | CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP)) |
9bfb23fc | 2419 | return -EINVAL; |
cf2e340f | 2420 | /* |
12c641ab EB |
2421 | * Not implemented, but pretend it works if there is nothing |
2422 | * to unshare. Note that unsharing the address space or the | |
2423 | * signal handlers also need to unshare the signal queues (aka | |
2424 | * CLONE_THREAD). | |
cf2e340f | 2425 | */ |
9bfb23fc | 2426 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { |
12c641ab EB |
2427 | if (!thread_group_empty(current)) |
2428 | return -EINVAL; | |
2429 | } | |
2430 | if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) { | |
2431 | if (atomic_read(¤t->sighand->count) > 1) | |
2432 | return -EINVAL; | |
2433 | } | |
2434 | if (unshare_flags & CLONE_VM) { | |
2435 | if (!current_is_single_threaded()) | |
9bfb23fc ON |
2436 | return -EINVAL; |
2437 | } | |
cf2e340f JD |
2438 | |
2439 | return 0; | |
2440 | } | |
2441 | ||
2442 | /* | |
99d1419d | 2443 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
2444 | */ |
2445 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
2446 | { | |
2447 | struct fs_struct *fs = current->fs; | |
2448 | ||
498052bb AV |
2449 | if (!(unshare_flags & CLONE_FS) || !fs) |
2450 | return 0; | |
2451 | ||
2452 | /* don't need lock here; in the worst case we'll do useless copy */ | |
2453 | if (fs->users == 1) | |
2454 | return 0; | |
2455 | ||
2456 | *new_fsp = copy_fs_struct(fs); | |
2457 | if (!*new_fsp) | |
2458 | return -ENOMEM; | |
cf2e340f JD |
2459 | |
2460 | return 0; | |
2461 | } | |
2462 | ||
cf2e340f | 2463 | /* |
a016f338 | 2464 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
2465 | */ |
2466 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
2467 | { | |
2468 | struct files_struct *fd = current->files; | |
a016f338 | 2469 | int error = 0; |
cf2e340f JD |
2470 | |
2471 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
2472 | (fd && atomic_read(&fd->count) > 1)) { |
2473 | *new_fdp = dup_fd(fd, &error); | |
2474 | if (!*new_fdp) | |
2475 | return error; | |
2476 | } | |
cf2e340f JD |
2477 | |
2478 | return 0; | |
2479 | } | |
2480 | ||
cf2e340f JD |
2481 | /* |
2482 | * unshare allows a process to 'unshare' part of the process | |
2483 | * context which was originally shared using clone. copy_* | |
2484 | * functions used by do_fork() cannot be used here directly | |
2485 | * because they modify an inactive task_struct that is being | |
2486 | * constructed. Here we are modifying the current, active, | |
2487 | * task_struct. | |
2488 | */ | |
9b32105e | 2489 | int ksys_unshare(unsigned long unshare_flags) |
cf2e340f | 2490 | { |
cf2e340f | 2491 | struct fs_struct *fs, *new_fs = NULL; |
cf2e340f | 2492 | struct files_struct *fd, *new_fd = NULL; |
b2e0d987 | 2493 | struct cred *new_cred = NULL; |
cf7b708c | 2494 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 2495 | int do_sysvsem = 0; |
9bfb23fc | 2496 | int err; |
cf2e340f | 2497 | |
b2e0d987 | 2498 | /* |
faf00da5 EB |
2499 | * If unsharing a user namespace must also unshare the thread group |
2500 | * and unshare the filesystem root and working directories. | |
b2e0d987 EB |
2501 | */ |
2502 | if (unshare_flags & CLONE_NEWUSER) | |
e66eded8 | 2503 | unshare_flags |= CLONE_THREAD | CLONE_FS; |
50804fe3 EB |
2504 | /* |
2505 | * If unsharing vm, must also unshare signal handlers. | |
2506 | */ | |
2507 | if (unshare_flags & CLONE_VM) | |
2508 | unshare_flags |= CLONE_SIGHAND; | |
12c641ab EB |
2509 | /* |
2510 | * If unsharing a signal handlers, must also unshare the signal queues. | |
2511 | */ | |
2512 | if (unshare_flags & CLONE_SIGHAND) | |
2513 | unshare_flags |= CLONE_THREAD; | |
9bfb23fc ON |
2514 | /* |
2515 | * If unsharing namespace, must also unshare filesystem information. | |
2516 | */ | |
2517 | if (unshare_flags & CLONE_NEWNS) | |
2518 | unshare_flags |= CLONE_FS; | |
50804fe3 EB |
2519 | |
2520 | err = check_unshare_flags(unshare_flags); | |
2521 | if (err) | |
2522 | goto bad_unshare_out; | |
6013f67f MS |
2523 | /* |
2524 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
2525 | * to a new ipc namespace, the semaphore arrays from the old | |
2526 | * namespace are unreachable. | |
2527 | */ | |
2528 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 2529 | do_sysvsem = 1; |
fb0a685c DRO |
2530 | err = unshare_fs(unshare_flags, &new_fs); |
2531 | if (err) | |
9bfb23fc | 2532 | goto bad_unshare_out; |
fb0a685c DRO |
2533 | err = unshare_fd(unshare_flags, &new_fd); |
2534 | if (err) | |
9bfb23fc | 2535 | goto bad_unshare_cleanup_fs; |
b2e0d987 | 2536 | err = unshare_userns(unshare_flags, &new_cred); |
fb0a685c | 2537 | if (err) |
9edff4ab | 2538 | goto bad_unshare_cleanup_fd; |
b2e0d987 EB |
2539 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
2540 | new_cred, new_fs); | |
2541 | if (err) | |
2542 | goto bad_unshare_cleanup_cred; | |
c0b2fc31 | 2543 | |
b2e0d987 | 2544 | if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { |
9edff4ab MS |
2545 | if (do_sysvsem) { |
2546 | /* | |
2547 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
2548 | */ | |
2549 | exit_sem(current); | |
2550 | } | |
ab602f79 JM |
2551 | if (unshare_flags & CLONE_NEWIPC) { |
2552 | /* Orphan segments in old ns (see sem above). */ | |
2553 | exit_shm(current); | |
2554 | shm_init_task(current); | |
2555 | } | |
ab516013 | 2556 | |
6f977e6b | 2557 | if (new_nsproxy) |
cf7b708c | 2558 | switch_task_namespaces(current, new_nsproxy); |
cf2e340f | 2559 | |
cf7b708c PE |
2560 | task_lock(current); |
2561 | ||
cf2e340f JD |
2562 | if (new_fs) { |
2563 | fs = current->fs; | |
2a4419b5 | 2564 | spin_lock(&fs->lock); |
cf2e340f | 2565 | current->fs = new_fs; |
498052bb AV |
2566 | if (--fs->users) |
2567 | new_fs = NULL; | |
2568 | else | |
2569 | new_fs = fs; | |
2a4419b5 | 2570 | spin_unlock(&fs->lock); |
cf2e340f JD |
2571 | } |
2572 | ||
cf2e340f JD |
2573 | if (new_fd) { |
2574 | fd = current->files; | |
2575 | current->files = new_fd; | |
2576 | new_fd = fd; | |
2577 | } | |
2578 | ||
2579 | task_unlock(current); | |
b2e0d987 EB |
2580 | |
2581 | if (new_cred) { | |
2582 | /* Install the new user namespace */ | |
2583 | commit_creds(new_cred); | |
2584 | new_cred = NULL; | |
2585 | } | |
cf2e340f JD |
2586 | } |
2587 | ||
e4222673 HB |
2588 | perf_event_namespaces(current); |
2589 | ||
b2e0d987 EB |
2590 | bad_unshare_cleanup_cred: |
2591 | if (new_cred) | |
2592 | put_cred(new_cred); | |
cf2e340f JD |
2593 | bad_unshare_cleanup_fd: |
2594 | if (new_fd) | |
2595 | put_files_struct(new_fd); | |
2596 | ||
cf2e340f JD |
2597 | bad_unshare_cleanup_fs: |
2598 | if (new_fs) | |
498052bb | 2599 | free_fs_struct(new_fs); |
cf2e340f | 2600 | |
cf2e340f JD |
2601 | bad_unshare_out: |
2602 | return err; | |
2603 | } | |
3b125388 | 2604 | |
9b32105e DB |
2605 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
2606 | { | |
2607 | return ksys_unshare(unshare_flags); | |
2608 | } | |
2609 | ||
3b125388 AV |
2610 | /* |
2611 | * Helper to unshare the files of the current task. | |
2612 | * We don't want to expose copy_files internals to | |
2613 | * the exec layer of the kernel. | |
2614 | */ | |
2615 | ||
2616 | int unshare_files(struct files_struct **displaced) | |
2617 | { | |
2618 | struct task_struct *task = current; | |
50704516 | 2619 | struct files_struct *copy = NULL; |
3b125388 AV |
2620 | int error; |
2621 | ||
2622 | error = unshare_fd(CLONE_FILES, ©); | |
2623 | if (error || !copy) { | |
2624 | *displaced = NULL; | |
2625 | return error; | |
2626 | } | |
2627 | *displaced = task->files; | |
2628 | task_lock(task); | |
2629 | task->files = copy; | |
2630 | task_unlock(task); | |
2631 | return 0; | |
2632 | } | |
16db3d3f HS |
2633 | |
2634 | int sysctl_max_threads(struct ctl_table *table, int write, | |
2635 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
2636 | { | |
2637 | struct ctl_table t; | |
2638 | int ret; | |
2639 | int threads = max_threads; | |
2640 | int min = MIN_THREADS; | |
2641 | int max = MAX_THREADS; | |
2642 | ||
2643 | t = *table; | |
2644 | t.data = &threads; | |
2645 | t.extra1 = &min; | |
2646 | t.extra2 = &max; | |
2647 | ||
2648 | ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
2649 | if (ret || !write) | |
2650 | return ret; | |
2651 | ||
2652 | set_max_threads(threads); | |
2653 | ||
2654 | return 0; | |
2655 | } |