From 8c32ae0e6df1c4dbd2eea98bc56b401d492e8f54 Mon Sep 17 00:00:00 2001 From: Markus Trippelsdorf Date: Wed, 16 Nov 2016 11:21:42 +0000 Subject: [PATCH] Fix PR78294 - thread sanitizer broken when using ld.gold When one uses ld.gold to build gcc, the thread sanitizer doesn't work, because gold is more conservative when applying TLS relaxations than ld.bfd. In this case a missing initial-exec attribute on a declaration causes gcc to assume the general dynamic model. With ld.bfd this gets relaxed to initial exec when linking the shared library, so the missing attribute doesn't matter. But ld.gold doesn't perform this optimization and this leads to crashes on tsan instrumented binaries. See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78294 and: https://sourceware.org/bugzilla/show_bug.cgi?id=20805 The fix is easy, just add the missing attribute. PR sanitizer/78294 * tsan/tsan_rtl.cc: Add missing attribute. From-SVN: r242480 --- libsanitizer/ChangeLog | 5 +++++ libsanitizer/tsan/tsan_rtl.cc | 1 + 2 files changed, 6 insertions(+) diff --git a/libsanitizer/ChangeLog b/libsanitizer/ChangeLog index e56cef9c8f4..215c44465bc 100644 --- a/libsanitizer/ChangeLog +++ b/libsanitizer/ChangeLog @@ -1,3 +1,8 @@ +2016-11-16 Markus Trippelsdorf + + PR sanitizer/78294 + * tsan/tsan_rtl.cc: Add missing attribute. + 2016-11-16 Maxim Ostapenko * LOCAL_PATCHES: New file. diff --git a/libsanitizer/tsan/tsan_rtl.cc b/libsanitizer/tsan/tsan_rtl.cc index 07fa165e939..5be28ce5502 100644 --- a/libsanitizer/tsan/tsan_rtl.cc +++ b/libsanitizer/tsan/tsan_rtl.cc @@ -43,6 +43,7 @@ extern "C" void __tsan_resume() { namespace __tsan { #if !SANITIZER_GO && !SANITIZER_MAC + __attribute__((tls_model("initial-exec"))) THREADLOCAL char cur_thread_placeholder[sizeof(ThreadState)] ALIGNED(64); #endif static char ctx_placeholder[sizeof(Context)] ALIGNED(64); -- 2.30.2