[compiler-rt] e065841 - [asan] Install `pthread_atfork` (#75290)

[via llvm-commits]

Author: Vitaly Buka
Date: 2023-12-13T13:42:24-08:00
New Revision: e065841cb06d78ae1d6863fac156a5e91f464ec7

URL: https://github.com/llvm/llvm-project/commit/e065841cb06d78ae1d6863fac156a5e91f464ec7
DIFF: https://github.com/llvm/llvm-project/commit/e065841cb06d78ae1d6863fac156a5e91f464ec7.diff

LOG: [asan] Install `pthread_atfork` (#75290)

This prevents deadlocks in forked process
if parent had more then one running threads.

Added: 
    

Modified: 
    compiler-rt/lib/asan/asan_fuchsia.cpp
    compiler-rt/lib/asan/asan_internal.h
    compiler-rt/lib/asan/asan_posix.cpp
    compiler-rt/lib/asan/asan_rtl.cpp
    compiler-rt/lib/asan/asan_win.cpp
    compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.c

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/asan/asan_fuchsia.cpp b/compiler-rt/lib/asan/asan_fuchsia.cpp
index 2b15504123bee7..12625e9d75833d 100644
--- a/compiler-rt/lib/asan/asan_fuchsia.cpp
+++ b/compiler-rt/lib/asan/asan_fuchsia.cpp
@@ -240,6 +240,8 @@ void FlushUnneededASanShadowMemory(uptr p, uptr size) {
 // So this doesn't install any atexit hook like on other platforms.
 void InstallAtExitCheckLeaks() {}
 
+void InstallAtForkHandler() {}
+
 }  // namespace __asan
 
 namespace __lsan {

diff  --git a/compiler-rt/lib/asan/asan_internal.h b/compiler-rt/lib/asan/asan_internal.h
index 5b97e77882cd67..2944ebe213b5d5 100644
--- a/compiler-rt/lib/asan/asan_internal.h
+++ b/compiler-rt/lib/asan/asan_internal.h
@@ -126,6 +126,7 @@ void *AsanDlSymNext(const char *sym);
 bool HandleDlopenInit();
 
 void InstallAtExitCheckLeaks();
+void InstallAtForkHandler();
 
 #define ASAN_ON_ERROR() \
   if (&__asan_on_error) \

diff  --git a/compiler-rt/lib/asan/asan_posix.cpp b/compiler-rt/lib/asan/asan_posix.cpp
index e1f66641617cc1..206551b6ef910e 100644
--- a/compiler-rt/lib/asan/asan_posix.cpp
+++ b/compiler-rt/lib/asan/asan_posix.cpp
@@ -148,6 +148,30 @@ void PlatformTSDDtor(void *tsd) {
 }
 #endif
 
+void InstallAtForkHandler() {
+  auto before = []() {
+    if (CAN_SANITIZE_LEAKS) {
+      __lsan::LockGlobal();
+    }
+    // `_lsan` functions defined regardless of `CAN_SANITIZE_LEAKS` and lock the
+    // stuff we need.
+    __lsan::LockThreads();
+    __lsan::LockAllocator();
+    StackDepotLockAll();
+  };
+  auto after = []() {
+    StackDepotUnlockAll();
+    // `_lsan` functions defined regardless of `CAN_SANITIZE_LEAKS` and unlock
+    // the stuff we need.
+    __lsan::UnlockAllocator();
+    __lsan::UnlockThreads();
+    if (CAN_SANITIZE_LEAKS) {
+      __lsan::UnlockGlobal();
+    }
+  };
+  pthread_atfork(before, after, after);
+}
+
 void InstallAtExitCheckLeaks() {
   if (CAN_SANITIZE_LEAKS) {
     if (common_flags()->detect_leaks && common_flags()->leak_check_at_exit) {

diff  --git a/compiler-rt/lib/asan/asan_rtl.cpp b/compiler-rt/lib/asan/asan_rtl.cpp
index b28f9f181239b3..a61deed7382b02 100644
--- a/compiler-rt/lib/asan/asan_rtl.cpp
+++ b/compiler-rt/lib/asan/asan_rtl.cpp
@@ -493,6 +493,8 @@ static bool AsanInitInternal() {
     InstallAtExitCheckLeaks();
   }
 
+  InstallAtForkHandler();
+
 #if CAN_SANITIZE_UB
   __ubsan::InitAsPlugin();
 #endif

diff  --git a/compiler-rt/lib/asan/asan_win.cpp b/compiler-rt/lib/asan/asan_win.cpp
index d5a30f471e2b0d..f16ce677618e4f 100644
--- a/compiler-rt/lib/asan/asan_win.cpp
+++ b/compiler-rt/lib/asan/asan_win.cpp
@@ -203,6 +203,8 @@ void InitializePlatformInterceptors() {
 
 void InstallAtExitCheckLeaks() {}
 
+void InstallAtForkHandler() {}
+
 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
   UNIMPLEMENTED();
 }

diff  --git a/compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.c b/compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.c
index 7592269608e64c..673d35346ba83f 100644
--- a/compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.c
+++ b/compiler-rt/test/sanitizer_common/TestCases/Posix/fork_threaded.c
@@ -1,6 +1,6 @@
 // RUN: %clang -O0 %s -o %t && %env_tool_opts=die_after_fork=0 %run %t
 
-// UNSUPPORTED: asan, hwasan
+// UNSUPPORTED: hwasan
 
 // The test uses pthread barriers which are not available on Darwin.
 // UNSUPPORTED: darwin