[compiler-rt] r224531 - tsan: disable __tls_get_addr interceptor

[Dmitry Vyukov]

Author: dvyukov
Date: Thu Dec 18 12:39:55 2014
New Revision: 224531

URL: http://llvm.org/viewvc/llvm-project?rev=224531&view=rev
Log:
tsan: disable __tls_get_addr interceptor

see the added comments for details, it's messy


Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
    compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc?rev=224531&r1=224530&r2=224531&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc Thu Dec 18 12:39:55 2014
@@ -3868,6 +3868,12 @@ INTERCEPTOR(__sanitizer_clock_t, times,
 
 #if SANITIZER_INTERCEPT_TLS_GET_ADDR
 #define INIT_TLS_GET_ADDR COMMON_INTERCEPT_FUNCTION(__tls_get_addr)
+// If you see any crashes around this functions, there are 2 known issues with
+// it: 1. __tls_get_addr can be called with mis-aligned stack due to:
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
+// 2. It can be called recursively if sanitizer code uses __tls_get_addr
+// to access thread local variables (it should not happen normally,
+// because sanitizers use initial-exec tls model).
 INTERCEPTOR(void *, __tls_get_addr, void *arg) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, __tls_get_addr, arg);

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc?rev=224531&r1=224530&r2=224531&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc Thu Dec 18 12:39:55 2014
@@ -2184,6 +2184,16 @@ static void HandleRecvmsg(ThreadState *t
 #undef SANITIZER_INTERCEPT_FGETPWENT
 #undef SANITIZER_INTERCEPT_GETPWNAM_AND_FRIENDS
 #undef SANITIZER_INTERCEPT_GETPWNAM_R_AND_FRIENDS
+// __tls_get_addr can be called with mis-aligned stack due to:
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
+// There are two potential issues:
+// 1. Sanitizer code contains a MOVDQA spill (it does not seem to be the case
+// right now). or 2. ProcessPendingSignal calls user handler which contains
+// MOVDQA spill (this happens right now).
+// Since the interceptor only initializes memory for msan, the simplest solution
+// is to disable the interceptor in tsan (other sanitizers do not call
+// signal handlers from COMMON_INTERCEPTOR_ENTER).
+#undef SANITIZER_INTERCEPT_TLS_GET_ADDR
 
 #define COMMON_INTERCEPT_FUNCTION(name) INTERCEPT_FUNCTION(name)