[compiler-rt] f2c2292 - [msan] Block signals in MsanThread::Init

[Vitaly Buka via llvm-commits]

Author: Vitaly Buka
Date: 2021-11-09T18:23:55-08:00
New Revision: f2c2292fa801896751cadec4f65bef88bf83ba5b

URL: https://github.com/llvm/llvm-project/commit/f2c2292fa801896751cadec4f65bef88bf83ba5b
DIFF: https://github.com/llvm/llvm-project/commit/f2c2292fa801896751cadec4f65bef88bf83ba5b.diff

LOG: [msan] Block signals in MsanThread::Init

If async signal handler called when we MsanThread::Init
signal handler may trigger false reports.
I failed to reproduce this locally for a test.

Differential Revision: https://reviews.llvm.org/D113328

Added: 
    

Modified: 
    compiler-rt/lib/msan/msan_interceptors.cpp
    compiler-rt/lib/msan/msan_thread.h

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/msan/msan_interceptors.cpp b/compiler-rt/lib/msan/msan_interceptors.cpp
index 46bdfa0e84d5a..a79221f3db9dd 100644
--- a/compiler-rt/lib/msan/msan_interceptors.cpp
+++ b/compiler-rt/lib/msan/msan_interceptors.cpp
@@ -1034,6 +1034,7 @@ static void *MsanThreadStartFunc(void *arg) {
   MsanThread *t = (MsanThread *)arg;
   SetCurrentThread(t);
   t->Init();
+  SetSigProcMask(&t->starting_sigset_, nullptr);
   return t->ThreadStart();
 }
 
@@ -1049,7 +1050,7 @@ INTERCEPTOR(int, pthread_create, void *th, void *attr, void *(*callback)(void*),
   AdjustStackSize(attr);
 
   MsanThread *t = MsanThread::Create(callback, param);
-
+  ScopedBlockSignals block(&t->starting_sigset_);
   int res = REAL(pthread_create)(th, attr, MsanThreadStartFunc, t);
 
   if (attr == &myattr)

diff  --git a/compiler-rt/lib/msan/msan_thread.h b/compiler-rt/lib/msan/msan_thread.h
index fe795e3a547ad..f6ed1534cccdf 100644
--- a/compiler-rt/lib/msan/msan_thread.h
+++ b/compiler-rt/lib/msan/msan_thread.h
@@ -15,7 +15,7 @@
 
 #include "msan_allocator.h"
 #include "sanitizer_common/sanitizer_common.h"
-
+#include "sanitizer_common/sanitizer_posix.h"
 namespace __msan {
 
 class MsanThread {
@@ -45,6 +45,7 @@ class MsanThread {
   MsanThreadLocalMallocStorage &malloc_storage() { return malloc_storage_; }
 
   int destructor_iterations_;
+  __sanitizer_sigset_t starting_sigset_;
 
  private:
   // NOTE: There is no MsanThread constructor. It is allocated