3 * POSIX signal handling support for Mono.
6 * Mono Team (mono-list@lists.ximian.com)
8 * Copyright 2001-2003 Ximian, Inc.
9 * Copyright 2003-2008 Ximian, Inc.
10 * Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
12 * See LICENSE for licensing information.
13 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
24 #ifdef HAVE_SYS_TIME_H
27 #ifdef HAVE_SYS_SYSCALL_H
28 #include <sys/syscall.h>
33 #include <mono/metadata/assembly.h>
34 #include <mono/metadata/loader.h>
35 #include <mono/metadata/tabledefs.h>
36 #include <mono/metadata/class.h>
37 #include <mono/metadata/object.h>
38 #include <mono/metadata/tokentype.h>
39 #include <mono/metadata/tabledefs.h>
40 #include <mono/metadata/threads.h>
41 #include <mono/metadata/appdomain.h>
42 #include <mono/metadata/debug-helpers.h>
43 #include "mono/metadata/profiler.h"
44 #include <mono/metadata/profiler-private.h>
45 #include <mono/metadata/mono-config.h>
46 #include <mono/metadata/environment.h>
47 #include <mono/metadata/mono-debug.h>
48 #include <mono/metadata/gc-internals.h>
49 #include <mono/metadata/threads-types.h>
50 #include <mono/metadata/verify.h>
51 #include <mono/metadata/verify-internals.h>
52 #include <mono/metadata/mempool-internals.h>
53 #include <mono/metadata/attach.h>
54 #include <mono/utils/mono-math.h>
55 #include <mono/utils/mono-compiler.h>
56 #include <mono/utils/mono-counters.h>
57 #include <mono/utils/mono-logger-internals.h>
58 #include <mono/utils/mono-mmap.h>
59 #include <mono/utils/dtrace.h>
60 #include <mono/utils/mono-signal-handler.h>
61 #include <mono/utils/mono-threads.h>
68 #include "debugger-agent.h"
70 #include "jit-icalls.h"
72 #ifdef PLATFORM_MACOSX
73 #include <mach/mach.h>
74 #include <mach/mach_time.h>
75 #include <mach/clock.h>
78 #if defined(HOST_WATCHOS)
81 mono_runtime_setup_stat_profiler (void)
83 printf("WARNING: mono_runtime_setup_stat_profiler() called!\n");
88 mono_runtime_shutdown_stat_profiler (void)
94 MONO_SIG_HANDLER_SIGNATURE (mono_chain_signal)
99 #ifndef PLATFORM_MACOSX
101 mono_runtime_install_handlers (void)
107 mono_runtime_posix_install_handlers(void)
109 /* we still need to ignore SIGPIPE */
110 signal (SIGPIPE, SIG_IGN);
114 mono_runtime_shutdown_handlers (void)
119 mono_runtime_cleanup_handlers (void)
125 static GHashTable *mono_saved_signal_handlers = NULL;
127 static struct sigaction *
128 get_saved_signal_handler (int signo, gboolean remove)
130 if (mono_saved_signal_handlers) {
131 /* The hash is only modified during startup, so no need for locking */
132 struct sigaction *handler = g_hash_table_lookup (mono_saved_signal_handlers, GINT_TO_POINTER (signo));
133 if (remove && handler)
134 g_hash_table_remove (mono_saved_signal_handlers, GINT_TO_POINTER (signo));
141 save_old_signal_handler (int signo, struct sigaction *old_action)
143 struct sigaction *handler_to_save = (struct sigaction *)g_malloc (sizeof (struct sigaction));
145 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_CONFIG,
146 "Saving old signal handler for signal %d.", signo);
148 if (! (old_action->sa_flags & SA_SIGINFO)) {
149 handler_to_save->sa_handler = old_action->sa_handler;
151 #ifdef MONO_ARCH_USE_SIGACTION
152 handler_to_save->sa_sigaction = old_action->sa_sigaction;
153 #endif /* MONO_ARCH_USE_SIGACTION */
155 handler_to_save->sa_mask = old_action->sa_mask;
156 handler_to_save->sa_flags = old_action->sa_flags;
158 if (!mono_saved_signal_handlers)
159 mono_saved_signal_handlers = g_hash_table_new_full (NULL, NULL, NULL, g_free);
160 g_hash_table_insert (mono_saved_signal_handlers, GINT_TO_POINTER (signo), handler_to_save);
164 free_saved_signal_handlers (void)
166 if (mono_saved_signal_handlers) {
167 g_hash_table_destroy (mono_saved_signal_handlers);
168 mono_saved_signal_handlers = NULL;
175 * Call the original signal handler for the signal given by the arguments, which
176 * should be the same as for a signal handler. Returns TRUE if the original handler
177 * was called, false otherwise.
180 MONO_SIG_HANDLER_SIGNATURE (mono_chain_signal)
182 int signal = MONO_SIG_HANDLER_GET_SIGNO ();
183 struct sigaction *saved_handler = (struct sigaction *)get_saved_signal_handler (signal, FALSE);
185 if (saved_handler && saved_handler->sa_handler) {
186 if (!(saved_handler->sa_flags & SA_SIGINFO)) {
187 saved_handler->sa_handler (signal);
189 #ifdef MONO_ARCH_USE_SIGACTION
190 saved_handler->sa_sigaction (MONO_SIG_HANDLER_PARAMS);
191 #endif /* MONO_ARCH_USE_SIGACTION */
198 MONO_SIG_HANDLER_FUNC (static, sigabrt_signal_handler)
200 MonoJitInfo *ji = NULL;
201 MONO_SIG_HANDLER_INFO_TYPE *info = MONO_SIG_HANDLER_GET_INFO ();
202 MONO_SIG_HANDLER_GET_CONTEXT;
204 if (mono_thread_internal_current ())
205 ji = mono_jit_info_table_find_internal (mono_domain_get (), (char *)mono_arch_ip_from_context (ctx), TRUE, TRUE);
207 if (mono_chain_signal (MONO_SIG_HANDLER_PARAMS))
209 mono_handle_native_crash ("SIGABRT", ctx, info);
213 #if defined(__i386__) || defined(__x86_64__)
214 #define FULL_STAT_PROFILER_BACKTRACE 1
215 #define CURRENT_FRAME_GET_BASE_POINTER(f) (* (gpointer*)(f))
216 #define CURRENT_FRAME_GET_RETURN_ADDRESS(f) (* (((gpointer*)(f)) + 1))
217 #if MONO_ARCH_STACK_GROWS_UP
218 #define IS_BEFORE_ON_STACK <
219 #define IS_AFTER_ON_STACK >
221 #define IS_BEFORE_ON_STACK >
222 #define IS_AFTER_ON_STACK <
225 #define FULL_STAT_PROFILER_BACKTRACE 0
228 #if (defined (USE_POSIX_BACKEND) && defined (SIGRTMIN)) || defined (SIGPROF)
229 #define HAVE_PROFILER_SIGNAL
232 #ifdef HAVE_PROFILER_SIGNAL
235 per_thread_profiler_hit (void *ctx)
237 int call_chain_depth = mono_profiler_stat_get_call_chain_depth ();
238 MonoProfilerCallChainStrategy call_chain_strategy = mono_profiler_stat_get_call_chain_strategy ();
240 if (call_chain_depth == 0) {
241 mono_profiler_stat_hit ((guchar *)mono_arch_ip_from_context (ctx), ctx);
243 MonoJitTlsData *jit_tls = (MonoJitTlsData *)mono_tls_get_jit_tls ();
244 int current_frame_index = 1;
245 MonoContext mono_context;
246 guchar *ips [call_chain_depth + 1];
248 mono_sigctx_to_monoctx (ctx, &mono_context);
249 ips [0] = (guchar *)MONO_CONTEXT_GET_IP (&mono_context);
251 if (jit_tls != NULL) {
252 if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_NATIVE) {
253 #if FULL_STAT_PROFILER_BACKTRACE
254 guchar *current_frame;
255 guchar *stack_bottom;
258 stack_bottom = (guchar *)jit_tls->end_of_stack;
259 stack_top = (guchar *)MONO_CONTEXT_GET_SP (&mono_context);
260 current_frame = (guchar *)MONO_CONTEXT_GET_BP (&mono_context);
262 while ((current_frame_index <= call_chain_depth) &&
263 (stack_bottom IS_BEFORE_ON_STACK (guchar*) current_frame) &&
264 ((guchar*) current_frame IS_BEFORE_ON_STACK stack_top)) {
265 ips [current_frame_index] = (guchar *)CURRENT_FRAME_GET_RETURN_ADDRESS (current_frame);
266 current_frame_index ++;
267 stack_top = current_frame;
268 current_frame = (guchar *)CURRENT_FRAME_GET_BASE_POINTER (current_frame);
271 call_chain_strategy = MONO_PROFILER_CALL_CHAIN_GLIBC;
275 if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_GLIBC) {
276 #if GLIBC_PROFILER_BACKTRACE
277 current_frame_index = backtrace ((void**) & ips [1], call_chain_depth);
279 call_chain_strategy = MONO_PROFILER_CALL_CHAIN_MANAGED;
283 if (call_chain_strategy == MONO_PROFILER_CALL_CHAIN_MANAGED) {
284 MonoDomain *domain = mono_domain_get ();
285 if (domain != NULL) {
289 MonoContext new_mono_context;
291 ji = mono_find_jit_info (domain, jit_tls, &res, NULL, &mono_context,
292 &new_mono_context, NULL, &lmf, &native_offset, NULL);
293 while ((ji != NULL) && (current_frame_index <= call_chain_depth)) {
294 ips [current_frame_index] = (guchar *)MONO_CONTEXT_GET_IP (&new_mono_context);
295 current_frame_index ++;
296 mono_context = new_mono_context;
297 ji = mono_find_jit_info (domain, jit_tls, &res, NULL, &mono_context,
298 &new_mono_context, NULL, &lmf, &native_offset, NULL);
304 mono_profiler_stat_call_chain (current_frame_index, & ips [0], ctx);
308 static MonoNativeThreadId sampling_thread;
310 static gint32 profiler_signals_sent;
311 static gint32 profiler_signals_received;
312 static gint32 profiler_signals_accepted;
313 static gint32 profiler_interrupt_signals_received;
315 MONO_SIG_HANDLER_FUNC (static, profiler_signal_handler)
317 int old_errno = errno;
319 MONO_SIG_HANDLER_GET_CONTEXT;
321 /* See the comment in mono_runtime_shutdown_stat_profiler (). */
322 if (mono_native_thread_id_get () == sampling_thread) {
323 InterlockedIncrement (&profiler_interrupt_signals_received);
327 InterlockedIncrement (&profiler_signals_received);
329 // Did a non-attached or detaching thread get the signal?
330 if (mono_thread_info_get_small_id () == -1 ||
331 !mono_domain_get () ||
332 !mono_tls_get_jit_tls ()) {
337 // See the comment in sampling_thread_func ().
338 InterlockedWrite (&mono_thread_info_current ()->profiler_signal_ack, 1);
340 InterlockedIncrement (&profiler_signals_accepted);
342 int hp_save_index = mono_hazard_pointer_save_for_signal_handler ();
344 mono_thread_info_set_is_async_context (TRUE);
345 per_thread_profiler_hit (ctx);
346 mono_thread_info_set_is_async_context (FALSE);
348 mono_hazard_pointer_restore_for_signal_handler (hp_save_index);
352 mono_chain_signal (MONO_SIG_HANDLER_PARAMS);
357 MONO_SIG_HANDLER_FUNC (static, sigquit_signal_handler)
361 /* We use this signal to start the attach agent too */
362 res = mono_attach_start ();
366 mono_threads_request_thread_dump ();
368 mono_chain_signal (MONO_SIG_HANDLER_PARAMS);
371 MONO_SIG_HANDLER_FUNC (static, sigusr2_signal_handler)
373 gboolean enabled = mono_trace_is_enabled ();
375 mono_trace_enable (!enabled);
377 mono_chain_signal (MONO_SIG_HANDLER_PARAMS);
381 add_signal_handler (int signo, gpointer handler, int flags)
384 struct sigaction previous_sa;
386 #ifdef MONO_ARCH_USE_SIGACTION
387 sa.sa_sigaction = (void (*)(int, siginfo_t *, void *))handler;
388 sigemptyset (&sa.sa_mask);
389 sa.sa_flags = SA_SIGINFO | flags;
390 #ifdef MONO_ARCH_SIGSEGV_ON_ALTSTACK
392 /*Apple likes to deliver SIGBUS for *0 */
393 #ifdef PLATFORM_MACOSX
394 if (signo == SIGSEGV || signo == SIGBUS) {
396 if (signo == SIGSEGV) {
398 sa.sa_flags |= SA_ONSTACK;
401 * libgc will crash when trying to do stack marking for threads which are on
402 * an altstack, so delay the suspend signal after the signal handler has
405 if (mono_gc_get_suspend_signal () != -1)
406 sigaddset (&sa.sa_mask, mono_gc_get_suspend_signal ());
409 if (signo == SIGSEGV) {
411 * Delay abort signals while handling SIGSEGVs since they could go unnoticed.
415 sigemptyset (&block_mask);
418 sa.sa_handler = handler;
419 sigemptyset (&sa.sa_mask);
422 g_assert (sigaction (signo, &sa, &previous_sa) != -1);
424 /* if there was already a handler in place for this signal, store it */
425 if (! (previous_sa.sa_flags & SA_SIGINFO) &&
426 (SIG_DFL == previous_sa.sa_handler)) {
427 /* it there is no sa_sigaction function and the sa_handler is default, we can safely ignore this */
429 if (mono_do_signal_chaining)
430 save_old_signal_handler (signo, &previous_sa);
435 remove_signal_handler (int signo)
438 struct sigaction *saved_action = get_saved_signal_handler (signo, TRUE);
441 sa.sa_handler = SIG_DFL;
442 sigemptyset (&sa.sa_mask);
445 sigaction (signo, &sa, NULL);
447 g_assert (sigaction (signo, saved_action, NULL) != -1);
452 mono_runtime_posix_install_handlers (void)
457 if (mini_get_debug_options ()->handle_sigint)
458 add_signal_handler (SIGINT, mono_sigint_signal_handler, SA_RESTART);
460 add_signal_handler (SIGFPE, mono_sigfpe_signal_handler, 0);
461 add_signal_handler (SIGQUIT, sigquit_signal_handler, SA_RESTART);
462 add_signal_handler (SIGILL, mono_sigill_signal_handler, 0);
463 add_signal_handler (SIGBUS, mono_sigsegv_signal_handler, 0);
464 if (mono_jit_trace_calls != NULL)
465 add_signal_handler (SIGUSR2, sigusr2_signal_handler, SA_RESTART);
467 /* it seems to have become a common bug for some programs that run as parents
468 * of many processes to block signal delivery for real time signals.
469 * We try to detect and work around their breakage here.
471 sigemptyset (&signal_set);
472 if (mono_gc_get_suspend_signal () != -1)
473 sigaddset (&signal_set, mono_gc_get_suspend_signal ());
474 if (mono_gc_get_restart_signal () != -1)
475 sigaddset (&signal_set, mono_gc_get_restart_signal ());
476 sigaddset (&signal_set, SIGCHLD);
477 sigprocmask (SIG_UNBLOCK, &signal_set, NULL);
479 signal (SIGPIPE, SIG_IGN);
481 add_signal_handler (SIGABRT, sigabrt_signal_handler, 0);
484 add_signal_handler (SIGSEGV, mono_sigsegv_signal_handler, 0);
487 #ifndef PLATFORM_MACOSX
489 mono_runtime_install_handlers (void)
491 mono_runtime_posix_install_handlers ();
496 mono_runtime_cleanup_handlers (void)
498 if (mini_get_debug_options ()->handle_sigint)
499 remove_signal_handler (SIGINT);
501 remove_signal_handler (SIGFPE);
502 remove_signal_handler (SIGQUIT);
503 remove_signal_handler (SIGILL);
504 remove_signal_handler (SIGBUS);
505 if (mono_jit_trace_calls != NULL)
506 remove_signal_handler (SIGUSR2);
508 remove_signal_handler (SIGABRT);
510 remove_signal_handler (SIGSEGV);
512 free_saved_signal_handlers ();
515 #ifdef HAVE_PROFILER_SIGNAL
517 static volatile gint32 sampling_thread_running;
519 #ifdef PLATFORM_MACOSX
521 static clock_serv_t sampling_clock_service;
529 ret = host_get_clock_service (mach_host_self (), SYSTEM_CLOCK, &sampling_clock_service);
530 } while (ret == KERN_ABORTED);
532 if (ret != KERN_SUCCESS)
533 g_error ("%s: host_get_clock_service () returned %d", __func__, ret);
542 ret = mach_port_deallocate (mach_task_self (), sampling_clock_service);
543 } while (ret == KERN_ABORTED);
545 if (ret != KERN_SUCCESS)
546 g_error ("%s: mach_port_deallocate () returned %d", __func__, ret);
550 clock_get_time_ns (void)
553 mach_timespec_t mach_ts;
556 ret = clock_get_time (sampling_clock_service, &mach_ts);
557 } while (ret == KERN_ABORTED);
559 if (ret != KERN_SUCCESS)
560 g_error ("%s: clock_get_time () returned %d", __func__, ret);
562 return ((guint64) mach_ts.tv_sec * 1000000000) + (guint64) mach_ts.tv_nsec;
566 clock_sleep_ns_abs (guint64 ns_abs)
569 mach_timespec_t then, remain_unused;
571 then.tv_sec = ns_abs / 1000000000;
572 then.tv_nsec = ns_abs % 1000000000;
575 ret = clock_sleep (sampling_clock_service, TIME_ABSOLUTE, then, &remain_unused);
577 if (ret != KERN_SUCCESS && ret != KERN_ABORTED)
578 g_error ("%s: clock_sleep () returned %d", __func__, ret);
579 } while (ret == KERN_ABORTED && InterlockedRead (&sampling_thread_running));
584 clockid_t sampling_posix_clock;
589 switch (mono_profiler_get_sampling_mode ()) {
590 case MONO_PROFILER_STAT_MODE_PROCESS: {
592 * If we don't have clock_nanosleep (), measuring the process time
593 * makes very little sense as we can only use nanosleep () to sleep on
596 #ifdef HAVE_CLOCK_NANOSLEEP
597 struct timespec ts = { 0 };
600 * Some systems (e.g. Windows Subsystem for Linux) declare the
601 * CLOCK_PROCESS_CPUTIME_ID clock but don't actually support it. For
602 * those systems, we fall back to CLOCK_MONOTONIC if we get EINVAL.
604 if (clock_nanosleep (CLOCK_PROCESS_CPUTIME_ID, TIMER_ABSTIME, &ts, NULL) != EINVAL) {
605 sampling_posix_clock = CLOCK_PROCESS_CPUTIME_ID;
612 case MONO_PROFILER_STAT_MODE_REAL: sampling_posix_clock = CLOCK_MONOTONIC; break;
613 default: g_assert_not_reached (); break;
623 clock_get_time_ns (void)
627 if (clock_gettime (sampling_posix_clock, &ts) == -1)
628 g_error ("%s: clock_gettime () returned -1, errno = %d", __func__, errno);
630 return ((guint64) ts.tv_sec * 1000000000) + (guint64) ts.tv_nsec;
634 clock_sleep_ns_abs (guint64 ns_abs)
636 #ifdef HAVE_CLOCK_NANOSLEEP
638 struct timespec then;
640 then.tv_sec = ns_abs / 1000000000;
641 then.tv_nsec = ns_abs % 1000000000;
644 ret = clock_nanosleep (sampling_posix_clock, TIMER_ABSTIME, &then, NULL);
646 if (ret != 0 && ret != EINTR)
647 g_error ("%s: clock_nanosleep () returned %d", __func__, ret);
648 } while (ret == EINTR && InterlockedRead (&sampling_thread_running));
655 * What follows is a crude attempt at emulating clock_nanosleep () on OSs
656 * which don't provide it (e.g. FreeBSD).
658 * The problem with nanosleep () is that if it is interrupted by a signal,
659 * time will drift as a result of having to restart the call after the
660 * signal handler has finished. For this reason, we avoid using the rem
661 * argument of nanosleep (). Instead, before every nanosleep () call, we
662 * check if enough time has passed to satisfy the sleep request. If yes, we
663 * simply return. If not, we calculate the difference and do another sleep.
665 * This should reduce the amount of drift that happens because we account
666 * for the time spent executing the signal handler, which nanosleep () is
667 * not guaranteed to do for the rem argument.
669 * The downside to this approach is that it is slightly expensive: We have
670 * to make an extra system call to retrieve the current time whenever we're
671 * going to restart a nanosleep () call. This is unlikely to be a problem
672 * in practice since the sampling thread won't be receiving many signals in
673 * the first place (it's a tools thread, so no STW), and because typical
674 * sleep periods for the thread are many orders of magnitude bigger than
675 * the time it takes to actually perform that system call (just a few
679 diff = (gint64) ns_abs - (gint64) clock_get_time_ns ();
684 req.tv_sec = diff / 1000000000;
685 req.tv_nsec = diff % 1000000000;
687 if ((ret = nanosleep (&req, NULL)) == -1 && errno != EINTR)
688 g_error ("%s: nanosleep () returned -1, errno = %d", __func__, errno);
689 } while (ret == -1 && InterlockedRead (&sampling_thread_running));
695 static int profiler_signal;
696 static volatile gint32 sampling_thread_exiting;
698 static mono_native_thread_return_t
699 sampling_thread_func (void *data)
701 mono_threads_attach_tools_thread ();
702 mono_native_thread_set_name (mono_native_thread_id_get (), "Profiler sampler");
704 gint64 rate = 1000000000 / mono_profiler_get_sampling_rate ();
707 struct sched_param old_sched;
708 pthread_getschedparam (pthread_self (), &old_policy, &old_sched);
711 * Attempt to switch the thread to real time scheduling. This will not
712 * necessarily work on all OSs; for example, most Linux systems will give
713 * us EPERM here unless configured to allow this.
715 * TODO: This does not work on Mac (and maybe some other OSs). On Mac, we
716 * have to use the Mach thread policy routines to switch to real-time
717 * scheduling. This is quite tricky as we need to specify how often we'll
718 * be doing work (easy), the normal processing time needed (also easy),
719 * and the maximum amount of processing time needed (hard). This is
720 * further complicated by the fact that if we misbehave and take too long
721 * to do our work, the kernel may knock us back down to the normal thread
722 * scheduling policy without telling us.
724 struct sched_param sched = { .sched_priority = sched_get_priority_max (SCHED_FIFO) };
725 pthread_setschedparam (pthread_self (), SCHED_FIFO, &sched);
729 guint64 sleep = clock_get_time_ns ();
731 while (InterlockedRead (&sampling_thread_running)) {
734 FOREACH_THREAD_SAFE (info) {
735 /* info should never be this thread as we're a tools thread. */
736 g_assert (mono_thread_info_get_tid (info) != mono_native_thread_id_get ());
739 * Require an ack for the last sampling signal sent to the thread
740 * so that we don't overflow the signal queue, leading to all sorts
741 * of problems (e.g. GC STW failing).
743 if (profiler_signal != SIGPROF && !InterlockedCompareExchange (&info->profiler_signal_ack, 0, 1))
746 mono_threads_pthread_kill (info, profiler_signal);
747 InterlockedIncrement (&profiler_signals_sent);
748 } FOREACH_THREAD_SAFE_END
750 clock_sleep_ns_abs (sleep);
753 InterlockedWrite (&sampling_thread_exiting, 1);
757 pthread_setschedparam (pthread_self (), old_policy, &old_sched);
759 mono_thread_info_detach ();
765 mono_runtime_shutdown_stat_profiler (void)
767 InterlockedWrite (&sampling_thread_running, 0);
769 #ifndef PLATFORM_MACOSX
771 * There is a slight problem when we're using CLOCK_PROCESS_CPUTIME_ID: If
772 * we're shutting down and there's largely no activity in the process other
773 * than waiting for the sampler thread to shut down, it can take upwards of
774 * 20 seconds (depending on a lot of factors) for us to shut down because
775 * the sleep progresses very slowly as a result of the low CPU activity.
777 * We fix this by repeatedly sending the profiler signal to the sampler
778 * thread in order to interrupt the sleep. clock_sleep_ns_abs () will check
779 * sampling_thread_running upon an interrupt and return immediately if it's
780 * zero. profiler_signal_handler () has a special case to ignore the signal
781 * for the sampler thread.
783 MonoThreadInfo *info;
785 // Did it shut down already?
786 if ((info = mono_thread_info_lookup (sampling_thread))) {
787 while (!InterlockedRead (&sampling_thread_exiting)) {
788 mono_threads_pthread_kill (info, profiler_signal);
789 mono_thread_info_usleep (10 * 1000 /* 10ms */);
792 // Make sure info can be freed.
793 mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
797 mono_native_thread_join (sampling_thread);
800 * We can't safely remove the signal handler because we have no guarantee
801 * that all pending signals have been delivered at this point. This should
802 * not really be a problem anyway.
804 //remove_signal_handler (profiler_signal);
808 mono_runtime_setup_stat_profiler (void)
811 * Use a real-time signal when possible. This gives us roughly a 99% signal
812 * delivery rate in all cases. On the other hand, using a regular signal
813 * tends to result in awful delivery rates when the application is heavily
816 * We avoid real-time signals on Android as they're super broken in certain
817 * API levels (too small sigset_t, nonsensical SIGRTMIN/SIGRTMAX values,
820 * TODO: On Mac, we should explore using the Mach thread suspend/resume
821 * functions and doing the stack walk from the sampling thread. This would
822 * get us a 100% sampling rate. However, this may interfere with the GC's
823 * STW logic. Could perhaps be solved by taking the suspend lock.
825 #if defined (USE_POSIX_BACKEND) && defined (SIGRTMIN) && !defined (PLATFORM_ANDROID)
826 /* Just take the first real-time signal we can get. */
827 profiler_signal = mono_threads_suspend_search_alternative_signal ();
829 profiler_signal = SIGPROF;
832 add_signal_handler (profiler_signal, profiler_signal_handler, SA_RESTART);
834 mono_counters_register ("Sampling signals sent", MONO_COUNTER_UINT | MONO_COUNTER_PROFILER | MONO_COUNTER_MONOTONIC, &profiler_signals_sent);
835 mono_counters_register ("Sampling signals received", MONO_COUNTER_UINT | MONO_COUNTER_PROFILER | MONO_COUNTER_MONOTONIC, &profiler_signals_received);
836 mono_counters_register ("Sampling signals accepted", MONO_COUNTER_UINT | MONO_COUNTER_PROFILER | MONO_COUNTER_MONOTONIC, &profiler_signals_accepted);
837 mono_counters_register ("Shutdown signals received", MONO_COUNTER_UINT | MONO_COUNTER_PROFILER | MONO_COUNTER_MONOTONIC, &profiler_interrupt_signals_received);
839 InterlockedWrite (&sampling_thread_running, 1);
840 mono_native_thread_create (&sampling_thread, sampling_thread_func, NULL);
846 mono_runtime_shutdown_stat_profiler (void)
851 mono_runtime_setup_stat_profiler (void)
857 #endif /* defined(HOST_WATCHOS) */
860 native_stack_with_gdb (pid_t crashed_pid, const char **argv, FILE *commands, char* commands_filename)
864 gdb = g_find_program_in_path ("gdb");
871 argv [3] = commands_filename;
874 fprintf (commands, "attach %ld\n", (long) crashed_pid);
875 fprintf (commands, "info threads\n");
876 fprintf (commands, "thread apply all bt\n");
883 native_stack_with_lldb (pid_t crashed_pid, const char **argv, FILE *commands, char* commands_filename)
887 lldb = g_find_program_in_path ("lldb");
892 argv [1] = "--batch";
893 argv [2] = "--source";
894 argv [3] = commands_filename;
895 argv [4] = "--no-lldbinit";
897 fprintf (commands, "process attach --pid %ld\n", (long) crashed_pid);
898 fprintf (commands, "thread list\n");
899 fprintf (commands, "thread backtrace all\n");
900 fprintf (commands, "detach\n");
901 fprintf (commands, "quit\n");
907 mono_gdb_render_native_backtraces (pid_t crashed_pid)
910 const char *argv [10];
912 char commands_filename [] = "/tmp/mono-gdb-commands.XXXXXX";
914 if (mkstemp (commands_filename) == -1)
917 commands = fopen (commands_filename, "w");
919 unlink (commands_filename);
923 memset (argv, 0, sizeof (char*) * 10);
925 #if defined(PLATFORM_MACOSX)
926 if (native_stack_with_lldb (crashed_pid, argv, commands, commands_filename))
930 if (native_stack_with_gdb (crashed_pid, argv, commands, commands_filename))
933 #if !defined(PLATFORM_MACOSX)
934 if (native_stack_with_lldb (crashed_pid, argv, commands, commands_filename))
938 fprintf (stderr, "mono_gdb_render_native_backtraces not supported on this platform, unable to find gdb or lldb\n");
941 unlink (commands_filename);
946 execv (argv [0], (char**)argv);
950 fprintf (stderr, "mono_gdb_render_native_backtraces not supported on this platform\n");
954 #if !defined (__MACH__)
957 mono_thread_state_init_from_handle (MonoThreadUnwindState *tctx, MonoThreadInfo *info)
959 g_error ("Posix systems don't support mono_thread_state_init_from_handle");