[compiler-rt] be77afe - tsan: Add a missing disable_sanitizer_instrumentation attribute

[Alexander Potapenko via llvm-commits]

Author: Alexander Potapenko
Date: 2022-02-17T15:34:41+01:00
New Revision: be77afe43dd39f517ab2468c359fd0d5633d9be6

URL: https://github.com/llvm/llvm-project/commit/be77afe43dd39f517ab2468c359fd0d5633d9be6
DIFF: https://github.com/llvm/llvm-project/commit/be77afe43dd39f517ab2468c359fd0d5633d9be6.diff

LOG: tsan: Add a missing disable_sanitizer_instrumentation attribute

Turns out the test was working by accident: we need to ensure
TSan instrumentation is not called from the fork() hook, otherwise the
tool will deadlock. Previously it worked because alloc_free_blocks() got
inlined into __tsan_test_only_on_fork(), but it cannot always be the
case.

Adding __attribute__((disable_sanitizer_instrumentation)) will prevent
TSan from instrumenting alloc_free_blocks().

Reviewed By: dvyukov

Differential Revision: https://reviews.llvm.org/D120050

Added: 
    

Modified: 
    compiler-rt/test/tsan/Linux/fork_deadlock.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/test/tsan/Linux/fork_deadlock.cpp b/compiler-rt/test/tsan/Linux/fork_deadlock.cpp
index 8f38ab92e69f6..952507032df65 100644
--- a/compiler-rt/test/tsan/Linux/fork_deadlock.cpp
+++ b/compiler-rt/test/tsan/Linux/fork_deadlock.cpp
@@ -11,7 +11,10 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 
-void alloc_free_blocks() {
+// disable_sanitizer_instrumentation on __tsan_test_only_on_fork is not
+// transitive, so we must apply it here as well.
+// Instrumenting alloc_free_blocks() will result in deadlocks in TSan.
+__attribute__((disable_sanitizer_instrumentation)) void alloc_free_blocks() {
   // Allocate a bunch of blocks to drain local allocator cache
   // and provoke it to lock allocator global mutexes.
   const int kBlocks = 1000;