[PATCH] D48806: [asan] Fix deadlock issue on FreeBSD, caused by use of .preinit_array in rL325240

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
Herald added subscribers: Sanitizers, llvm-commits, delcypher, krytarowski, kubamracek, srhines.

Without this patch,
clang -fsanitize=address a.c; ./a => deadlock in AsanTSDInit>pthread_key_create at PLT


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D48806

Files:
  lib/sanitizer_common/sanitizer_internal_defs.h


Index: lib/sanitizer_common/sanitizer_internal_defs.h
===================================================================
--- lib/sanitizer_common/sanitizer_internal_defs.h
+++ lib/sanitizer_common/sanitizer_internal_defs.h
@@ -98,10 +98,14 @@
 
 // We can use .preinit_array section on Linux to call sanitizer initialization
 // functions very early in the process startup (unless PIC macro is defined).
+//
+// On FreeBSD, .preinit_array functions are called with rtld_bind_lock writer
+// lock held. It will lead to dead lock if unresolved PLT functions (which helds
+// rtld_bind_lock reader lock) are called inside .preinit_array functions.
+//
 // FIXME: do we have anything like this on Mac?
 #ifndef SANITIZER_CAN_USE_PREINIT_ARRAY
-#if ((SANITIZER_LINUX && !SANITIZER_ANDROID) || \
-  SANITIZER_FREEBSD || SANITIZER_OPENBSD) && !defined(PIC)
+#if ((SANITIZER_LINUX && !SANITIZER_ANDROID) || SANITIZER_OPENBSD) && !defined(PIC)
 # define SANITIZER_CAN_USE_PREINIT_ARRAY 1
 // Before Solaris 11.4, .preinit_array is fully supported only with GNU ld.
 // FIXME: Check for those conditions.


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