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[mono][threads] save/restore errno in thread state transitions #79856

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Merged
merged 2 commits into from
Jul 12, 2023
Merged

[mono][threads] save/restore errno in thread state transitions #79856

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b464614
[threads] Save errno when using posix semaphores for thread transitions
lambdageek Dec 20, 2022
b09d29f
rename W32_DEFINE_LAST_ERROR_RESTORE_POINT to MONO_DEFINE_LAST_ERROR_…
lambdageek Dec 20, 2022
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12 changes: 6 additions & 6 deletions src/mono/mono/utils/mono-threads-coop.c
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Original file line number Diff line number Diff line change
Expand Up @@ -337,10 +337,10 @@ mono_threads_exit_gc_safe_region_internal (gpointer cookie, MonoStackData *stack
return;

#ifdef ENABLE_CHECKED_BUILD_GC
W32_DEFINE_LAST_ERROR_RESTORE_POINT;
MONO_DEFINE_LAST_ERROR_RESTORE_POINT;
if (mono_check_mode_enabled (MONO_CHECK_MODE_GC))
coop_tls_pop (cookie);
W32_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;
MONO_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;
#endif

mono_threads_exit_gc_safe_region_unbalanced_internal (cookie, stackdata);
Expand All @@ -365,7 +365,7 @@ mono_threads_exit_gc_safe_region_unbalanced_internal (gpointer cookie, MonoStack
/* Common to use enter/exit gc safe around OS API's affecting last error. */
/* This method can call OS API's that will reset last error on some platforms. */
/* To reduce errors, we need to restore last error before exit gc safe. */
W32_DEFINE_LAST_ERROR_RESTORE_POINT;
MONO_DEFINE_LAST_ERROR_RESTORE_POINT;

info = (MonoThreadInfo *)cookie;

Expand Down Expand Up @@ -398,7 +398,7 @@ mono_threads_exit_gc_safe_region_unbalanced_internal (gpointer cookie, MonoStack
info->user_data = NULL;
}

W32_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;
MONO_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;
}

void
Expand Down Expand Up @@ -652,14 +652,14 @@ mono_threads_suspend_policy_init (void)
// otherwise if one of the old environment variables is set, use that.
// otherwise use full preemptive suspend.

W32_DEFINE_LAST_ERROR_RESTORE_POINT;
MONO_DEFINE_LAST_ERROR_RESTORE_POINT;

(policy = threads_suspend_policy_getenv ())
|| (policy = threads_suspend_policy_default ())
|| (policy = threads_suspend_policy_getenv_compat ())
|| (policy = MONO_THREADS_SUSPEND_FULL_PREEMPTIVE);

W32_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;
MONO_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;

g_assert (policy);
mono_threads_suspend_policy_hidden_dont_modify = (char)policy;
Expand Down
4 changes: 2 additions & 2 deletions src/mono/mono/utils/mono-threads.c
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Expand Up @@ -1938,7 +1938,7 @@ mono_thread_info_uninstall_interrupt (gboolean *interrupted)
/* Common to uninstall interrupt handler around OS API's affecting last error. */
/* This method could call OS API's on some platforms that will reset last error so make sure to restore */
/* last error before exit. */
W32_DEFINE_LAST_ERROR_RESTORE_POINT;
MONO_DEFINE_LAST_ERROR_RESTORE_POINT;

g_assert (interrupted);
*interrupted = FALSE;
Expand All @@ -1961,7 +1961,7 @@ mono_thread_info_uninstall_interrupt (gboolean *interrupted)
THREADS_INTERRUPT_DEBUG ("interrupt uninstall tid %p previous_token %p interrupted %s\n",
mono_thread_info_get_tid (info), previous_token, *interrupted ? "TRUE" : "FALSE");

W32_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;
MONO_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;
}

static MonoThreadInfoInterruptToken*
Expand Down
41 changes: 36 additions & 5 deletions src/mono/mono/utils/mono-threads.h
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Expand Up @@ -871,19 +871,50 @@ mono_win32_interrupt_wait (PVOID thread_info, HANDLE native_thread_handle, DWORD
void
mono_win32_abort_blocking_io_call (THREAD_INFO_TYPE *info);

#define W32_DEFINE_LAST_ERROR_RESTORE_POINT \
#else


#endif

#ifdef USE_WINDOWS_BACKEND

/* APC calls can change GetLastError while a thread is suspended. Save/restore it when doing thread
state transitions (for example in m2n wrappers) in order to protect the result of the last
pinvoke */

#define MONO_DEFINE_LAST_ERROR_RESTORE_POINT \
const DWORD _last_error_restore_point = GetLastError ();

#define W32_RESTORE_LAST_ERROR_FROM_RESTORE_POINT \
#define MONO_RESTORE_LAST_ERROR_FROM_RESTORE_POINT \
/* Only restore if changed to prevent unnecessary writes. */ \
if (GetLastError () != _last_error_restore_point) \
mono_SetLastError (_last_error_restore_point);

#else
#elif defined(USE_WASM_BACKEND) || defined (USE_POSIX_BACKEND)

#define W32_DEFINE_LAST_ERROR_RESTORE_POINT /* nothing */
#define W32_RESTORE_LAST_ERROR_FROM_RESTORE_POINT /* nothing */
#define MONO_DEFINE_LAST_ERROR_RESTORE_POINT \
int _last_errno_restore_point = errno;

#define MONO_RESTORE_LAST_ERROR_FROM_RESTORE_POINT \
if (errno != _last_errno_restore_point) \
errno = _last_errno_restore_point;

/* Posix semaphores set errno on failure and sporadic wakeup. GC state transitions are done in n2m
* and m2n wrappers and may change the value of errno from the last pinvoke. Use these macros to
* save/restore errno when doing thread state transitions. */

#elif defined(USE_MACH_BACKEND)

/* Mach semaphores don't set errno on failure. Change this to be the same as POSIX if some other primitives used
in thread state transitions pollute errno. */

#define MONO_DEFINE_LAST_ERROR_RESTORE_POINT /* nothing */
#define MONO_RESTORE_LAST_ERROR_FROM_RESTORE_POINT /* nothing */

#else
#error "unknown threads backend, not sure how to save/restore last error"
#endif



#endif /* __MONO_THREADS_H__ */