gecko-dev/build/build-clang/tsan-D101154.patch

diff --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
@@ -1976,7 +1976,8 @@
   // because in async signal processing case (when handler is called directly
   // from rtl_generic_sighandler) we have not yet received the reraised
   // signal; and it looks too fragile to intercept all ways to reraise a signal.
-  if (flags()->report_bugs && !sync && sig != SIGTERM && errno != 99) {
+  if (ShouldReport(thr, ReportTypeErrnoInSignal) && !sync && sig != SIGTERM &&
+      errno != 99) {
     VarSizeStackTrace stack;
     // StackTrace::GetNestInstructionPc(pc) is used because return address is
     // expected, OutputReport() will undo this.
diff --git a/compiler-rt/lib/tsan/rtl/tsan_mman.cpp b/compiler-rt/lib/tsan/rtl/tsan_mman.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_mman.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_mman.cpp
@@ -145,7 +145,7 @@
 
 static void SignalUnsafeCall(ThreadState *thr, uptr pc) {
   if (atomic_load_relaxed(&thr->in_signal_handler) == 0 ||
-      !flags()->report_signal_unsafe)
+      !ShouldReport(thr, ReportTypeSignalUnsafe))
     return;
   VarSizeStackTrace stack;
   ObtainCurrentStack(thr, pc, &stack);
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl.h b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
@@ -624,6 +624,7 @@
   ScopedErrorReportLock lock_;
 };
 
+bool ShouldReport(ThreadState *thr, ReportType typ);
 ThreadContext *IsThreadStackOrTls(uptr addr, bool *is_stack);
 void RestoreStack(int tid, const u64 epoch, VarSizeStackTrace *stk,
                   MutexSet *mset, uptr *tag = nullptr);
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp b/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
@@ -519,23 +519,22 @@
 void ForkBefore(ThreadState *thr, uptr pc) {
   ctx->thread_registry->Lock();
   ctx->report_mtx.Lock();
-  // Ignore memory accesses in the pthread_atfork callbacks.
-  // If any of them triggers a data race we will deadlock
-  // on the report_mtx.
+  // Suppress all reports in the pthread_atfork callbacks.
+  // Reports will deadlock on the report_mtx.
   // We could ignore interceptors and sync operations as well,
   // but so far it's unclear if it will do more good or harm.
   // Unnecessarily ignoring things can lead to false positives later.
-  ThreadIgnoreBegin(thr, pc);
+  thr->suppress_reports++;
 }
 
 void ForkParentAfter(ThreadState *thr, uptr pc) {
-  ThreadIgnoreEnd(thr, pc);  // Begin is in ForkBefore.
+  thr->suppress_reports--;  // Enabled in ForkBefore.
   ctx->report_mtx.Unlock();
   ctx->thread_registry->Unlock();
 }
 
 void ForkChildAfter(ThreadState *thr, uptr pc) {
-  ThreadIgnoreEnd(thr, pc);  // Begin is in ForkBefore.
+  thr->suppress_reports--;  // Enabled in ForkBefore.
   ctx->report_mtx.Unlock();
   ctx->thread_registry->Unlock();
 
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl_mutex.cpp b/compiler-rt/lib/tsan/rtl/tsan_rtl_mutex.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl_mutex.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl_mutex.cpp
@@ -51,6 +51,8 @@
   // or false positives (e.g. unlock in a different thread).
   if (SANITIZER_GO)
     return;
+  if (!ShouldReport(thr, typ))
+    return;
   ThreadRegistryLock l(ctx->thread_registry);
   ScopedReport rep(typ);
   rep.AddMutex(mid);
@@ -107,7 +109,7 @@
   if (!unlock_locked)
     s->Reset(thr->proc());  // must not reset it before the report is printed
   s->mtx.Unlock();
-  if (unlock_locked) {
+  if (unlock_locked && ShouldReport(thr, ReportTypeMutexDestroyLocked)) {
     ThreadRegistryLock l(ctx->thread_registry);
     ScopedReport rep(ReportTypeMutexDestroyLocked);
     rep.AddMutex(mid);
@@ -534,7 +536,7 @@
 }
 
 void ReportDeadlock(ThreadState *thr, uptr pc, DDReport *r) {
-  if (r == 0)
+  if (r == 0 || !ShouldReport(thr, ReportTypeDeadlock))
     return;
   ThreadRegistryLock l(ctx->thread_registry);
   ScopedReport rep(ReportTypeDeadlock);
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp b/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp
@@ -142,6 +142,27 @@
   return stack;
 }
 
+bool ShouldReport(ThreadState *thr, ReportType typ) {
+  // We set thr->suppress_reports in the fork context.
+  // Taking any locking in the fork context can lead to deadlocks.
+  // If any locks are already taken, it's too late to do this check.
+  CheckNoLocks(thr);
+  if (SANITIZER_DEBUG)
+    ThreadRegistryLock l(ctx->thread_registry);
+  if (!flags()->report_bugs || thr->suppress_reports)
+    return false;
+  switch (typ) {
+    case ReportTypeSignalUnsafe:
+      return flags()->report_signal_unsafe;
+    case ReportTypeThreadLeak:
+      return flags()->report_thread_leaks;
+    case ReportTypeMutexDestroyLocked:
+      return flags()->report_destroy_locked;
+    default:
+      return true;
+  }
+}
+
 ScopedReportBase::ScopedReportBase(ReportType typ, uptr tag) {
   ctx->thread_registry->CheckLocked();
   void *mem = internal_alloc(MBlockReport, sizeof(ReportDesc));
@@ -497,8 +518,10 @@
 }
 
 bool OutputReport(ThreadState *thr, const ScopedReport &srep) {
-  if (!flags()->report_bugs || thr->suppress_reports)
-    return false;
+  // These should have been checked in ShouldReport.
+  // It's too late to check them here, we have already taken locks.
+  CHECK(flags()->report_bugs);
+  CHECK(!thr->suppress_reports);
   atomic_store_relaxed(&ctx->last_symbolize_time_ns, NanoTime());
   const ReportDesc *rep = srep.GetReport();
   CHECK_EQ(thr->current_report, nullptr);
@@ -589,7 +612,7 @@
   // at best it will cause deadlocks on internal mutexes.
   ScopedIgnoreInterceptors ignore;
 
-  if (!flags()->report_bugs)
+  if (!ShouldReport(thr, ReportTypeRace))
     return;
   if (!flags()->report_atomic_races && !RaceBetweenAtomicAndFree(thr))
     return;
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl_thread.cpp b/compiler-rt/lib/tsan/rtl/tsan_rtl_thread.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl_thread.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl_thread.cpp
@@ -210,7 +210,7 @@
 void ThreadFinalize(ThreadState *thr) {
   ThreadCheckIgnore(thr);
 #if !SANITIZER_GO
-  if (!flags()->report_thread_leaks)
+  if (!ShouldReport(thr, ReportTypeThreadLeak))
     return;
   ThreadRegistryLock l(ctx->thread_registry);
   Vector<ThreadLeak> leaks;
diff --git a/compiler-rt/test/tsan/pthread_atfork_deadlock3.c b/compiler-rt/test/tsan/pthread_atfork_deadlock3.c
new file mode 100644
--- /dev/null
+++ b/compiler-rt/test/tsan/pthread_atfork_deadlock3.c
@@ -0,0 +1,71 @@
+// RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+// Regression test for
+// https://groups.google.com/g/thread-sanitizer/c/TQrr4-9PRYo/m/HFR4FMi6AQAJ
+#include "test.h"
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <string.h>
+#include <signal.h>
+
+long glob = 0;
+
+void *worker(void *main) {
+  glob++;
+  barrier_wait(&barrier);
+  barrier_wait(&barrier);
+  pthread_kill((pthread_t)main, SIGPROF);
+  barrier_wait(&barrier);
+  return NULL;
+}
+
+void atfork() {
+  barrier_wait(&barrier);
+  barrier_wait(&barrier);
+  write(2, "in atfork\n", strlen("in atfork\n"));
+  static volatile long a;
+  __atomic_fetch_add(&a, 1, __ATOMIC_RELEASE);
+}
+
+void handler(int sig) {
+  write(2, "in handler\n", strlen("in handler\n"));
+  glob++;
+}
+
+int main() {
+  barrier_init(&barrier, 2);
+  struct sigaction act = {};
+  act.sa_handler = &handler;
+  if (sigaction(SIGPROF, &act, 0)) {
+    perror("sigaction");
+    exit(1);
+  }
+  pthread_atfork(atfork, NULL, NULL);
+  pthread_t t;
+  pthread_create(&t, NULL, worker, (void*)pthread_self());
+  barrier_wait(&barrier);
+  pid_t pid = fork();
+  if (pid < 0) {
+    fprintf(stderr, "fork failed: %d\n", errno);
+    return 1;
+  }
+  if (pid == 0) {
+    fprintf(stderr, "CHILD\n");
+    return 0;
+  }
+  if (pid != waitpid(pid, NULL, 0)) {
+    fprintf(stderr, "waitpid failed: %d\n", errno);
+    return 1;
+  }
+  pthread_join(t, NULL);
+  fprintf(stderr, "PARENT\n");
+  return 0;
+}
+
+// CHECK: in atfork
+// CHECK: in handler
+// Note: There is a race, but we won't report it
+// to not deadlock.
+// CHECK-NOT: ThreadSanitizer: data race
+// CHECK: CHILD
+// CHECK: PARENT