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1a59d1b8 1// SPDX-License-Identifier: GPL-2.0-or-later
97e1c18e 2/*
de7b2973 3 * Copyright (C) 2008-2014 Mathieu Desnoyers
97e1c18e
MD
4 */
5#include <linux/module.h>
6#include <linux/mutex.h>
7#include <linux/types.h>
8#include <linux/jhash.h>
9#include <linux/list.h>
10#include <linux/rcupdate.h>
11#include <linux/tracepoint.h>
12#include <linux/err.h>
13#include <linux/slab.h>
3f07c014 14#include <linux/sched/signal.h>
29930025 15#include <linux/sched/task.h>
c5905afb 16#include <linux/static_key.h>
97e1c18e 17
9c0be3f6
MD
18extern tracepoint_ptr_t __start___tracepoints_ptrs[];
19extern tracepoint_ptr_t __stop___tracepoints_ptrs[];
97e1c18e 20
e6753f23
JFG
21DEFINE_SRCU(tracepoint_srcu);
22EXPORT_SYMBOL_GPL(tracepoint_srcu);
23
97e1c18e
MD
24/* Set to 1 to enable tracepoint debug output */
25static const int tracepoint_debug;
26
de7b2973 27#ifdef CONFIG_MODULES
97e1c18e 28/*
de7b2973 29 * Tracepoint module list mutex protects the local module list.
97e1c18e 30 */
de7b2973 31static DEFINE_MUTEX(tracepoint_module_list_mutex);
97e1c18e 32
de7b2973 33/* Local list of struct tp_module */
b75ef8b4
MD
34static LIST_HEAD(tracepoint_module_list);
35#endif /* CONFIG_MODULES */
36
97e1c18e 37/*
de7b2973
MD
38 * tracepoints_mutex protects the builtin and module tracepoints.
39 * tracepoints_mutex nests inside tracepoint_module_list_mutex.
97e1c18e 40 */
de7b2973 41static DEFINE_MUTEX(tracepoints_mutex);
97e1c18e 42
f8a79d5c
SRV
43static struct rcu_head *early_probes;
44static bool ok_to_free_tracepoints;
45
97e1c18e
MD
46/*
47 * Note about RCU :
fd589a8f 48 * It is used to delay the free of multiple probes array until a quiescent
97e1c18e 49 * state is reached.
97e1c18e 50 */
19dba33c 51struct tp_probes {
0dea6d52 52 struct rcu_head rcu;
38516ab5 53 struct tracepoint_func probes[0];
19dba33c 54};
97e1c18e 55
19dba33c 56static inline void *allocate_probes(int count)
97e1c18e 57{
f0553dcb
GS
58 struct tp_probes *p = kmalloc(struct_size(p, probes, count),
59 GFP_KERNEL);
19dba33c 60 return p == NULL ? NULL : p->probes;
97e1c18e
MD
61}
62
e6753f23 63static void srcu_free_old_probes(struct rcu_head *head)
97e1c18e 64{
0dea6d52 65 kfree(container_of(head, struct tp_probes, rcu));
19dba33c
LJ
66}
67
e6753f23
JFG
68static void rcu_free_old_probes(struct rcu_head *head)
69{
70 call_srcu(&tracepoint_srcu, head, srcu_free_old_probes);
71}
72
f8a79d5c
SRV
73static __init int release_early_probes(void)
74{
75 struct rcu_head *tmp;
76
77 ok_to_free_tracepoints = true;
78
79 while (early_probes) {
80 tmp = early_probes;
81 early_probes = tmp->next;
74401729 82 call_rcu(tmp, rcu_free_old_probes);
f8a79d5c
SRV
83 }
84
85 return 0;
86}
87
88/* SRCU is initialized at core_initcall */
89postcore_initcall(release_early_probes);
90
38516ab5 91static inline void release_probes(struct tracepoint_func *old)
19dba33c
LJ
92{
93 if (old) {
94 struct tp_probes *tp_probes = container_of(old,
95 struct tp_probes, probes[0]);
f8a79d5c
SRV
96
97 /*
98 * We can't free probes if SRCU is not initialized yet.
99 * Postpone the freeing till after SRCU is initialized.
100 */
101 if (unlikely(!ok_to_free_tracepoints)) {
102 tp_probes->rcu.next = early_probes;
103 early_probes = &tp_probes->rcu;
104 return;
105 }
106
e6753f23
JFG
107 /*
108 * Tracepoint probes are protected by both sched RCU and SRCU,
109 * by calling the SRCU callback in the sched RCU callback we
110 * cover both cases. So let us chain the SRCU and sched RCU
111 * callbacks to wait for both grace periods.
112 */
74401729 113 call_rcu(&tp_probes->rcu, rcu_free_old_probes);
19dba33c 114 }
97e1c18e
MD
115}
116
de7b2973 117static void debug_print_probes(struct tracepoint_func *funcs)
97e1c18e
MD
118{
119 int i;
120
de7b2973 121 if (!tracepoint_debug || !funcs)
97e1c18e
MD
122 return;
123
de7b2973
MD
124 for (i = 0; funcs[i].func; i++)
125 printk(KERN_DEBUG "Probe %d : %p\n", i, funcs[i].func);
97e1c18e
MD
126}
127
7904b5c4
SRRH
128static struct tracepoint_func *
129func_add(struct tracepoint_func **funcs, struct tracepoint_func *tp_func,
130 int prio)
97e1c18e 131{
38516ab5 132 struct tracepoint_func *old, *new;
7904b5c4
SRRH
133 int nr_probes = 0;
134 int pos = -1;
97e1c18e 135
de7b2973 136 if (WARN_ON(!tp_func->func))
4c69e6ea 137 return ERR_PTR(-EINVAL);
97e1c18e 138
de7b2973
MD
139 debug_print_probes(*funcs);
140 old = *funcs;
97e1c18e
MD
141 if (old) {
142 /* (N -> N+1), (N != 0, 1) probes */
7904b5c4
SRRH
143 for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
144 /* Insert before probes of lower priority */
145 if (pos < 0 && old[nr_probes].prio < prio)
146 pos = nr_probes;
de7b2973
MD
147 if (old[nr_probes].func == tp_func->func &&
148 old[nr_probes].data == tp_func->data)
97e1c18e 149 return ERR_PTR(-EEXIST);
7904b5c4 150 }
97e1c18e
MD
151 }
152 /* + 2 : one for new probe, one for NULL func */
19dba33c 153 new = allocate_probes(nr_probes + 2);
97e1c18e
MD
154 if (new == NULL)
155 return ERR_PTR(-ENOMEM);
7904b5c4
SRRH
156 if (old) {
157 if (pos < 0) {
158 pos = nr_probes;
159 memcpy(new, old, nr_probes * sizeof(struct tracepoint_func));
160 } else {
161 /* Copy higher priority probes ahead of the new probe */
162 memcpy(new, old, pos * sizeof(struct tracepoint_func));
163 /* Copy the rest after it. */
164 memcpy(new + pos + 1, old + pos,
165 (nr_probes - pos) * sizeof(struct tracepoint_func));
166 }
167 } else
168 pos = 0;
169 new[pos] = *tp_func;
38516ab5 170 new[nr_probes + 1].func = NULL;
de7b2973
MD
171 *funcs = new;
172 debug_print_probes(*funcs);
97e1c18e
MD
173 return old;
174}
175
de7b2973
MD
176static void *func_remove(struct tracepoint_func **funcs,
177 struct tracepoint_func *tp_func)
97e1c18e
MD
178{
179 int nr_probes = 0, nr_del = 0, i;
38516ab5 180 struct tracepoint_func *old, *new;
97e1c18e 181
de7b2973 182 old = *funcs;
97e1c18e 183
f66af459 184 if (!old)
19dba33c 185 return ERR_PTR(-ENOENT);
f66af459 186
de7b2973 187 debug_print_probes(*funcs);
97e1c18e 188 /* (N -> M), (N > 1, M >= 0) probes */
de7b2973 189 if (tp_func->func) {
4c69e6ea 190 for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
de7b2973
MD
191 if (old[nr_probes].func == tp_func->func &&
192 old[nr_probes].data == tp_func->data)
4c69e6ea
S
193 nr_del++;
194 }
97e1c18e
MD
195 }
196
4c69e6ea
S
197 /*
198 * If probe is NULL, then nr_probes = nr_del = 0, and then the
199 * entire entry will be removed.
200 */
97e1c18e
MD
201 if (nr_probes - nr_del == 0) {
202 /* N -> 0, (N > 1) */
de7b2973
MD
203 *funcs = NULL;
204 debug_print_probes(*funcs);
97e1c18e
MD
205 return old;
206 } else {
207 int j = 0;
208 /* N -> M, (N > 1, M > 0) */
209 /* + 1 for NULL */
19dba33c 210 new = allocate_probes(nr_probes - nr_del + 1);
97e1c18e
MD
211 if (new == NULL)
212 return ERR_PTR(-ENOMEM);
38516ab5 213 for (i = 0; old[i].func; i++)
de7b2973
MD
214 if (old[i].func != tp_func->func
215 || old[i].data != tp_func->data)
97e1c18e 216 new[j++] = old[i];
38516ab5 217 new[nr_probes - nr_del].func = NULL;
de7b2973 218 *funcs = new;
97e1c18e 219 }
de7b2973 220 debug_print_probes(*funcs);
97e1c18e
MD
221 return old;
222}
223
224/*
de7b2973 225 * Add the probe function to a tracepoint.
97e1c18e 226 */
de7b2973 227static int tracepoint_add_func(struct tracepoint *tp,
7904b5c4 228 struct tracepoint_func *func, int prio)
97e1c18e 229{
de7b2973 230 struct tracepoint_func *old, *tp_funcs;
8cf868af 231 int ret;
97e1c18e 232
8cf868af
SRRH
233 if (tp->regfunc && !static_key_enabled(&tp->key)) {
234 ret = tp->regfunc();
235 if (ret < 0)
236 return ret;
237 }
97e1c18e 238
b725dfea
MD
239 tp_funcs = rcu_dereference_protected(tp->funcs,
240 lockdep_is_held(&tracepoints_mutex));
7904b5c4 241 old = func_add(&tp_funcs, func, prio);
de7b2973 242 if (IS_ERR(old)) {
d66a270b 243 WARN_ON_ONCE(PTR_ERR(old) != -ENOMEM);
de7b2973
MD
244 return PTR_ERR(old);
245 }
97419875 246
97e1c18e 247 /*
243d1a79
PM
248 * rcu_assign_pointer has as smp_store_release() which makes sure
249 * that the new probe callbacks array is consistent before setting
250 * a pointer to it. This array is referenced by __DO_TRACE from
251 * include/linux/tracepoint.h using rcu_dereference_sched().
97e1c18e 252 */
de7b2973
MD
253 rcu_assign_pointer(tp->funcs, tp_funcs);
254 if (!static_key_enabled(&tp->key))
255 static_key_slow_inc(&tp->key);
8058bd0f 256 release_probes(old);
de7b2973 257 return 0;
97e1c18e
MD
258}
259
260/*
de7b2973 261 * Remove a probe function from a tracepoint.
97e1c18e
MD
262 * Note: only waiting an RCU period after setting elem->call to the empty
263 * function insures that the original callback is not used anymore. This insured
264 * by preempt_disable around the call site.
265 */
de7b2973
MD
266static int tracepoint_remove_func(struct tracepoint *tp,
267 struct tracepoint_func *func)
97e1c18e 268{
de7b2973 269 struct tracepoint_func *old, *tp_funcs;
97e1c18e 270
b725dfea
MD
271 tp_funcs = rcu_dereference_protected(tp->funcs,
272 lockdep_is_held(&tracepoints_mutex));
de7b2973
MD
273 old = func_remove(&tp_funcs, func);
274 if (IS_ERR(old)) {
d66a270b 275 WARN_ON_ONCE(PTR_ERR(old) != -ENOMEM);
de7b2973 276 return PTR_ERR(old);
97e1c18e 277 }
b75ef8b4 278
de7b2973
MD
279 if (!tp_funcs) {
280 /* Removed last function */
281 if (tp->unregfunc && static_key_enabled(&tp->key))
282 tp->unregfunc();
b75ef8b4 283
de7b2973
MD
284 if (static_key_enabled(&tp->key))
285 static_key_slow_dec(&tp->key);
127cafbb 286 }
de7b2973 287 rcu_assign_pointer(tp->funcs, tp_funcs);
8058bd0f 288 release_probes(old);
de7b2973 289 return 0;
127cafbb
LJ
290}
291
97e1c18e 292/**
f39e2391 293 * tracepoint_probe_register_prio - Connect a probe to a tracepoint with priority
de7b2973 294 * @tp: tracepoint
97e1c18e 295 * @probe: probe handler
cac92ba7 296 * @data: tracepoint data
7904b5c4 297 * @prio: priority of this function over other registered functions
97e1c18e 298 *
de7b2973
MD
299 * Returns 0 if ok, error value on error.
300 * Note: if @tp is within a module, the caller is responsible for
301 * unregistering the probe before the module is gone. This can be
302 * performed either with a tracepoint module going notifier, or from
303 * within module exit functions.
97e1c18e 304 */
7904b5c4
SRRH
305int tracepoint_probe_register_prio(struct tracepoint *tp, void *probe,
306 void *data, int prio)
97e1c18e 307{
de7b2973
MD
308 struct tracepoint_func tp_func;
309 int ret;
97e1c18e
MD
310
311 mutex_lock(&tracepoints_mutex);
de7b2973
MD
312 tp_func.func = probe;
313 tp_func.data = data;
7904b5c4
SRRH
314 tp_func.prio = prio;
315 ret = tracepoint_add_func(tp, &tp_func, prio);
b75ef8b4 316 mutex_unlock(&tracepoints_mutex);
b196e2b9 317 return ret;
97e1c18e 318}
7904b5c4
SRRH
319EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio);
320
321/**
322 * tracepoint_probe_register - Connect a probe to a tracepoint
323 * @tp: tracepoint
324 * @probe: probe handler
325 * @data: tracepoint data
7904b5c4
SRRH
326 *
327 * Returns 0 if ok, error value on error.
328 * Note: if @tp is within a module, the caller is responsible for
329 * unregistering the probe before the module is gone. This can be
330 * performed either with a tracepoint module going notifier, or from
331 * within module exit functions.
332 */
333int tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data)
334{
335 return tracepoint_probe_register_prio(tp, probe, data, TRACEPOINT_DEFAULT_PRIO);
336}
97e1c18e
MD
337EXPORT_SYMBOL_GPL(tracepoint_probe_register);
338
339/**
340 * tracepoint_probe_unregister - Disconnect a probe from a tracepoint
de7b2973 341 * @tp: tracepoint
97e1c18e 342 * @probe: probe function pointer
cac92ba7 343 * @data: tracepoint data
97e1c18e 344 *
de7b2973 345 * Returns 0 if ok, error value on error.
97e1c18e 346 */
de7b2973 347int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
97e1c18e 348{
de7b2973
MD
349 struct tracepoint_func tp_func;
350 int ret;
97e1c18e
MD
351
352 mutex_lock(&tracepoints_mutex);
de7b2973
MD
353 tp_func.func = probe;
354 tp_func.data = data;
355 ret = tracepoint_remove_func(tp, &tp_func);
b75ef8b4 356 mutex_unlock(&tracepoints_mutex);
de7b2973 357 return ret;
97e1c18e
MD
358}
359EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
360
9c0be3f6
MD
361static void for_each_tracepoint_range(
362 tracepoint_ptr_t *begin, tracepoint_ptr_t *end,
46e0c9be
AB
363 void (*fct)(struct tracepoint *tp, void *priv),
364 void *priv)
365{
9c0be3f6
MD
366 tracepoint_ptr_t *iter;
367
46e0c9be
AB
368 if (!begin)
369 return;
9c0be3f6
MD
370 for (iter = begin; iter < end; iter++)
371 fct(tracepoint_ptr_deref(iter), priv);
46e0c9be
AB
372}
373
227a8375 374#ifdef CONFIG_MODULES
45ab2813
SRRH
375bool trace_module_has_bad_taint(struct module *mod)
376{
66cc69e3
MD
377 return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
378 (1 << TAINT_UNSIGNED_MODULE));
45ab2813
SRRH
379}
380
de7b2973
MD
381static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);
382
383/**
384 * register_tracepoint_notifier - register tracepoint coming/going notifier
385 * @nb: notifier block
386 *
387 * Notifiers registered with this function are called on module
388 * coming/going with the tracepoint_module_list_mutex held.
389 * The notifier block callback should expect a "struct tp_module" data
390 * pointer.
391 */
392int register_tracepoint_module_notifier(struct notifier_block *nb)
393{
394 struct tp_module *tp_mod;
395 int ret;
396
397 mutex_lock(&tracepoint_module_list_mutex);
398 ret = blocking_notifier_chain_register(&tracepoint_notify_list, nb);
399 if (ret)
400 goto end;
401 list_for_each_entry(tp_mod, &tracepoint_module_list, list)
402 (void) nb->notifier_call(nb, MODULE_STATE_COMING, tp_mod);
403end:
404 mutex_unlock(&tracepoint_module_list_mutex);
405 return ret;
406}
407EXPORT_SYMBOL_GPL(register_tracepoint_module_notifier);
408
409/**
410 * unregister_tracepoint_notifier - unregister tracepoint coming/going notifier
411 * @nb: notifier block
412 *
413 * The notifier block callback should expect a "struct tp_module" data
414 * pointer.
415 */
416int unregister_tracepoint_module_notifier(struct notifier_block *nb)
417{
418 struct tp_module *tp_mod;
419 int ret;
420
421 mutex_lock(&tracepoint_module_list_mutex);
422 ret = blocking_notifier_chain_unregister(&tracepoint_notify_list, nb);
423 if (ret)
424 goto end;
425 list_for_each_entry(tp_mod, &tracepoint_module_list, list)
426 (void) nb->notifier_call(nb, MODULE_STATE_GOING, tp_mod);
427end:
428 mutex_unlock(&tracepoint_module_list_mutex);
429 return ret;
430
431}
432EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
433
434/*
435 * Ensure the tracer unregistered the module's probes before the module
436 * teardown is performed. Prevents leaks of probe and data pointers.
437 */
46e0c9be 438static void tp_module_going_check_quiescent(struct tracepoint *tp, void *priv)
de7b2973 439{
46e0c9be 440 WARN_ON_ONCE(tp->funcs);
de7b2973
MD
441}
442
b75ef8b4
MD
443static int tracepoint_module_coming(struct module *mod)
444{
0dea6d52 445 struct tp_module *tp_mod;
b75ef8b4
MD
446 int ret = 0;
447
7dec935a
SRRH
448 if (!mod->num_tracepoints)
449 return 0;
450
b75ef8b4 451 /*
c10076c4
SR
452 * We skip modules that taint the kernel, especially those with different
453 * module headers (for forced load), to make sure we don't cause a crash.
66cc69e3 454 * Staging, out-of-tree, and unsigned GPL modules are fine.
b75ef8b4 455 */
45ab2813 456 if (trace_module_has_bad_taint(mod))
b75ef8b4 457 return 0;
de7b2973 458 mutex_lock(&tracepoint_module_list_mutex);
b75ef8b4
MD
459 tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);
460 if (!tp_mod) {
461 ret = -ENOMEM;
462 goto end;
463 }
eb7d035c 464 tp_mod->mod = mod;
0dea6d52 465 list_add_tail(&tp_mod->list, &tracepoint_module_list);
de7b2973
MD
466 blocking_notifier_call_chain(&tracepoint_notify_list,
467 MODULE_STATE_COMING, tp_mod);
b75ef8b4 468end:
de7b2973 469 mutex_unlock(&tracepoint_module_list_mutex);
b75ef8b4
MD
470 return ret;
471}
472
de7b2973 473static void tracepoint_module_going(struct module *mod)
b75ef8b4 474{
de7b2973 475 struct tp_module *tp_mod;
b75ef8b4 476
7dec935a 477 if (!mod->num_tracepoints)
de7b2973 478 return;
7dec935a 479
de7b2973
MD
480 mutex_lock(&tracepoint_module_list_mutex);
481 list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
eb7d035c 482 if (tp_mod->mod == mod) {
de7b2973
MD
483 blocking_notifier_call_chain(&tracepoint_notify_list,
484 MODULE_STATE_GOING, tp_mod);
485 list_del(&tp_mod->list);
486 kfree(tp_mod);
487 /*
488 * Called the going notifier before checking for
489 * quiescence.
490 */
46e0c9be
AB
491 for_each_tracepoint_range(mod->tracepoints_ptrs,
492 mod->tracepoints_ptrs + mod->num_tracepoints,
493 tp_module_going_check_quiescent, NULL);
b75ef8b4
MD
494 break;
495 }
496 }
497 /*
498 * In the case of modules that were tainted at "coming", we'll simply
499 * walk through the list without finding it. We cannot use the "tainted"
500 * flag on "going", in case a module taints the kernel only after being
501 * loaded.
502 */
de7b2973 503 mutex_unlock(&tracepoint_module_list_mutex);
b75ef8b4 504}
227a8375 505
de7b2973
MD
506static int tracepoint_module_notify(struct notifier_block *self,
507 unsigned long val, void *data)
32f85742
MD
508{
509 struct module *mod = data;
b75ef8b4 510 int ret = 0;
32f85742
MD
511
512 switch (val) {
513 case MODULE_STATE_COMING:
b75ef8b4
MD
514 ret = tracepoint_module_coming(mod);
515 break;
516 case MODULE_STATE_LIVE:
517 break;
32f85742 518 case MODULE_STATE_GOING:
de7b2973
MD
519 tracepoint_module_going(mod);
520 break;
521 case MODULE_STATE_UNFORMED:
32f85742
MD
522 break;
523 }
b75ef8b4 524 return ret;
32f85742
MD
525}
526
de7b2973 527static struct notifier_block tracepoint_module_nb = {
32f85742
MD
528 .notifier_call = tracepoint_module_notify,
529 .priority = 0,
530};
531
de7b2973 532static __init int init_tracepoints(void)
32f85742 533{
de7b2973
MD
534 int ret;
535
536 ret = register_module_notifier(&tracepoint_module_nb);
eb7d035c 537 if (ret)
a395d6a7 538 pr_warn("Failed to register tracepoint module enter notifier\n");
eb7d035c 539
de7b2973 540 return ret;
32f85742
MD
541}
542__initcall(init_tracepoints);
227a8375 543#endif /* CONFIG_MODULES */
a871bd33 544
de7b2973
MD
545/**
546 * for_each_kernel_tracepoint - iteration on all kernel tracepoints
547 * @fct: callback
548 * @priv: private data
549 */
550void for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
551 void *priv)
552{
553 for_each_tracepoint_range(__start___tracepoints_ptrs,
554 __stop___tracepoints_ptrs, fct, priv);
555}
556EXPORT_SYMBOL_GPL(for_each_kernel_tracepoint);
557
3d27d8cb 558#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
60d970c2 559
97419875 560/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
a871bd33
JB
561static int sys_tracepoint_refcount;
562
8cf868af 563int syscall_regfunc(void)
a871bd33 564{
8063e41d 565 struct task_struct *p, *t;
a871bd33 566
a871bd33 567 if (!sys_tracepoint_refcount) {
8063e41d
ON
568 read_lock(&tasklist_lock);
569 for_each_process_thread(p, t) {
ea73c79e 570 set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
8063e41d
ON
571 }
572 read_unlock(&tasklist_lock);
a871bd33
JB
573 }
574 sys_tracepoint_refcount++;
8cf868af
SRRH
575
576 return 0;
a871bd33
JB
577}
578
579void syscall_unregfunc(void)
580{
8063e41d 581 struct task_struct *p, *t;
a871bd33 582
a871bd33
JB
583 sys_tracepoint_refcount--;
584 if (!sys_tracepoint_refcount) {
8063e41d
ON
585 read_lock(&tasklist_lock);
586 for_each_process_thread(p, t) {
66700001 587 clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
8063e41d
ON
588 }
589 read_unlock(&tasklist_lock);
a871bd33 590 }
a871bd33 591}
60d970c2 592#endif