2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
5 #include <linux/kallsyms.h>
6 #include <linux/kprobes.h>
7 #include <linux/uaccess.h>
8 #include <linux/utsname.h>
9 #include <linux/hardirq.h>
10 #include <linux/kdebug.h>
11 #include <linux/module.h>
12 #include <linux/ptrace.h>
13 #include <linux/sched/debug.h>
14 #include <linux/sched/task_stack.h>
15 #include <linux/ftrace.h>
16 #include <linux/kexec.h>
17 #include <linux/bug.h>
18 #include <linux/nmi.h>
19 #include <linux/sysfs.h>
21 #include <asm/stacktrace.h>
22 #include <asm/unwind.h>
24 int panic_on_unrecovered_nmi
;
26 unsigned int code_bytes
= 64;
27 static int die_counter
;
29 bool in_task_stack(unsigned long *stack
, struct task_struct
*task
,
30 struct stack_info
*info
)
32 unsigned long *begin
= task_stack_page(task
);
33 unsigned long *end
= task_stack_page(task
) + THREAD_SIZE
;
35 if (stack
< begin
|| stack
>= end
)
38 info
->type
= STACK_TYPE_TASK
;
46 static void printk_stack_address(unsigned long address
, int reliable
,
50 printk("%s %s%pB\n", log_lvl
, reliable
? "" : "? ", (void *)address
);
53 void show_trace_log_lvl(struct task_struct
*task
, struct pt_regs
*regs
,
54 unsigned long *stack
, char *log_lvl
)
56 struct unwind_state state
;
57 struct stack_info stack_info
= {0};
58 unsigned long visit_mask
= 0;
61 printk("%sCall Trace:\n", log_lvl
);
63 unwind_start(&state
, task
, regs
, stack
);
64 stack
= stack
? : get_stack_pointer(task
, regs
);
67 * Iterate through the stacks, starting with the current stack pointer.
68 * Each stack has a pointer to the next one.
70 * x86-64 can have several stacks:
73 * - HW exception stacks (double fault, nmi, debug, mce)
75 * x86-32 can have up to three stacks:
80 for (regs
= NULL
; stack
; stack
= PTR_ALIGN(stack_info
.next_sp
, sizeof(long))) {
81 const char *stack_name
;
84 * If we overflowed the task stack into a guard page, jump back
85 * to the bottom of the usable stack.
87 if (task_stack_page(task
) - (void *)stack
< PAGE_SIZE
)
88 stack
= task_stack_page(task
);
90 if (get_stack_info(stack
, task
, &stack_info
, &visit_mask
))
93 stack_name
= stack_type_name(stack_info
.type
);
95 printk("%s <%s>\n", log_lvl
, stack_name
);
97 if (regs
&& on_stack(&stack_info
, regs
, sizeof(*regs
)))
101 * Scan the stack, printing any text addresses we find. At the
102 * same time, follow proper stack frames with the unwinder.
104 * Addresses found during the scan which are not reported by
105 * the unwinder are considered to be additional clues which are
106 * sometimes useful for debugging and are prefixed with '?'.
107 * This also serves as a failsafe option in case the unwinder
108 * goes off in the weeds.
110 for (; stack
< stack_info
.end
; stack
++) {
111 unsigned long real_addr
;
113 unsigned long addr
= READ_ONCE_NOCHECK(*stack
);
114 unsigned long *ret_addr_p
=
115 unwind_get_return_address_ptr(&state
);
117 if (!__kernel_text_address(addr
))
121 * Don't print regs->ip again if it was already printed
122 * by __show_regs() below.
124 if (regs
&& stack
== ®s
->ip
)
127 if (stack
== ret_addr_p
)
131 * When function graph tracing is enabled for a
132 * function, its return address on the stack is
133 * replaced with the address of an ftrace handler
134 * (return_to_handler). In that case, before printing
135 * the "real" address, we want to print the handler
136 * address as an "unreliable" hint that function graph
137 * tracing was involved.
139 real_addr
= ftrace_graph_ret_addr(task
, &graph_idx
,
141 if (real_addr
!= addr
)
142 printk_stack_address(addr
, 0, log_lvl
);
143 printk_stack_address(real_addr
, reliable
, log_lvl
);
150 * Get the next frame from the unwinder. No need to
151 * check for an error: if anything goes wrong, the rest
152 * of the addresses will just be printed as unreliable.
154 unwind_next_frame(&state
);
156 /* if the frame has entry regs, print them */
157 regs
= unwind_get_entry_regs(&state
);
158 if (regs
&& on_stack(&stack_info
, regs
, sizeof(*regs
)))
159 __show_regs(regs
, 0);
163 printk("%s </%s>\n", log_lvl
, stack_name
);
167 void show_stack(struct task_struct
*task
, unsigned long *sp
)
169 task
= task
? : current
;
172 * Stack frames below this one aren't interesting. Don't show them
173 * if we're printing for %current.
175 if (!sp
&& task
== current
)
176 sp
= get_stack_pointer(current
, NULL
);
178 show_trace_log_lvl(task
, NULL
, sp
, KERN_DEFAULT
);
181 void show_stack_regs(struct pt_regs
*regs
)
183 show_trace_log_lvl(current
, regs
, NULL
, KERN_DEFAULT
);
186 static arch_spinlock_t die_lock
= __ARCH_SPIN_LOCK_UNLOCKED
;
187 static int die_owner
= -1;
188 static unsigned int die_nest_count
;
190 unsigned long oops_begin(void)
197 /* racy, but better than risking deadlock. */
198 raw_local_irq_save(flags
);
199 cpu
= smp_processor_id();
200 if (!arch_spin_trylock(&die_lock
)) {
201 if (cpu
== die_owner
)
202 /* nested oops. should stop eventually */;
204 arch_spin_lock(&die_lock
);
212 EXPORT_SYMBOL_GPL(oops_begin
);
213 NOKPROBE_SYMBOL(oops_begin
);
215 void __noreturn
rewind_stack_do_exit(int signr
);
217 void oops_end(unsigned long flags
, struct pt_regs
*regs
, int signr
)
219 if (regs
&& kexec_should_crash(current
))
224 add_taint(TAINT_DIE
, LOCKDEP_NOW_UNRELIABLE
);
227 /* Nest count reaches zero, release the lock. */
228 arch_spin_unlock(&die_lock
);
229 raw_local_irq_restore(flags
);
235 panic("Fatal exception in interrupt");
237 panic("Fatal exception");
240 * We're not going to return, but we might be on an IST stack or
241 * have very little stack space left. Rewind the stack and kill
244 rewind_stack_do_exit(signr
);
246 NOKPROBE_SYMBOL(oops_end
);
248 int __die(const char *str
, struct pt_regs
*regs
, long err
)
255 "%s: %04lx [#%d]%s%s%s%s\n", str
, err
& 0xffff, ++die_counter
,
256 IS_ENABLED(CONFIG_PREEMPT
) ? " PREEMPT" : "",
257 IS_ENABLED(CONFIG_SMP
) ? " SMP" : "",
258 debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
259 IS_ENABLED(CONFIG_KASAN
) ? " KASAN" : "");
261 if (notify_die(DIE_OOPS
, str
, regs
, err
,
262 current
->thread
.trap_nr
, SIGSEGV
) == NOTIFY_STOP
)
268 if (user_mode(regs
)) {
272 sp
= kernel_stack_pointer(regs
);
275 printk(KERN_EMERG
"EIP: %pS SS:ESP: %04x:%08lx\n",
276 (void *)regs
->ip
, ss
, sp
);
278 /* Executive summary in case the oops scrolled away */
279 printk(KERN_ALERT
"RIP: %pS RSP: %016lx\n", (void *)regs
->ip
, regs
->sp
);
283 NOKPROBE_SYMBOL(__die
);
286 * This is gone through when something in the kernel has done something bad
287 * and is about to be terminated:
289 void die(const char *str
, struct pt_regs
*regs
, long err
)
291 unsigned long flags
= oops_begin();
294 if (__die(str
, regs
, err
))
296 oops_end(flags
, regs
, sig
);
299 static int __init
code_bytes_setup(char *s
)
307 ret
= kstrtoul(s
, 0, &val
);
312 if (code_bytes
> 8192)
317 __setup("code_bytes=", code_bytes_setup
);