[compiler-rt] 578e66a - [tsan] Intercept __tls_get_addr_earlier

[via llvm-commits]

Author: Alexander Richardson
Date: 2024-03-08T22:09:10-08:00
New Revision: 578e66ac45dfcc5c739f3525bfb82d71282d925c

URL: https://github.com/llvm/llvm-project/commit/578e66ac45dfcc5c739f3525bfb82d71282d925c
DIFF: https://github.com/llvm/llvm-project/commit/578e66ac45dfcc5c739f3525bfb82d71282d925c.diff

LOG: [tsan] Intercept __tls_get_addr_earlier

This can be useful because dlsym() may call malloc on failure which could
result in other interposed functions being called that could eventually
make use of TLS. While the crash that I experienced originally has been
fixed differently (by not using global-dynamic TLS accesses in the mutex
deadlock detector, see https://github.com/llvm/llvm-project/pull/83890),
moving this interception earlier is still a good since it makes the code
a bit more robust against initialization order problems.

Reviewed By: MaskRay, vitalybuka

Pull Request: https://github.com/llvm/llvm-project/pull/83886

Added: 
    

Modified: 
    compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
index a9f6673ac44e90..24309ab66b2e67 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
@@ -2863,6 +2863,17 @@ void InitializeInterceptors() {
 
   new(interceptor_ctx()) InterceptorContext();
 
+  // Interpose __tls_get_addr before the common interposers. This is needed
+  // because dlsym() may call malloc on failure which could result in other
+  // interposed functions being called that could eventually make use of TLS.
+#ifdef NEED_TLS_GET_ADDR
+#  if !SANITIZER_S390
+  TSAN_INTERCEPT(__tls_get_addr);
+#  else
+  TSAN_INTERCEPT(__tls_get_addr_internal);
+  TSAN_INTERCEPT(__tls_get_offset);
+#  endif
+#endif
   InitializeCommonInterceptors();
   InitializeSignalInterceptors();
   InitializeLibdispatchInterceptors();
@@ -3010,15 +3021,6 @@ void InitializeInterceptors() {
   TSAN_INTERCEPT(__cxa_atexit);
   TSAN_INTERCEPT(_exit);
 
-#ifdef NEED_TLS_GET_ADDR
-#if !SANITIZER_S390
-  TSAN_INTERCEPT(__tls_get_addr);
-#else
-  TSAN_INTERCEPT(__tls_get_addr_internal);
-  TSAN_INTERCEPT(__tls_get_offset);
-#endif
-#endif
-
   TSAN_MAYBE_INTERCEPT__LWP_EXIT;
   TSAN_MAYBE_INTERCEPT_THR_EXIT;