tsan: disable __tls_get_addr interceptor

see the added comments for details, it's messy

llvm-svn: 224531

2 files changed, 16 insertions, 0 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
index 274e87c3d67..8eb9949f18a 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -3868,6 +3868,12 @@ INTERCEPTOR(__sanitizer_clock_t, times, void *tms) {
 
 #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);
diff --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc b/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc
index fc742a56ace..b2bffe97779 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc
@@ -2184,6 +2184,16 @@ static void HandleRecvmsg(ThreadState *thr, uptr pc,
 #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)