From 6f19e5f213ac8ac1c02b0221127b3968adf88f70 Mon Sep 17 00:00:00 2001 From: trippels Date: Wed, 16 Nov 2016 11:28:57 +0000 Subject: 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. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-6-branch@242482 138bc75d-0d04-0410-961f-82ee72b054a4 --- libsanitizer/ChangeLog | 5 +++++ libsanitizer/tsan/tsan_rtl.cc | 1 + 2 files changed, 6 insertions(+) diff --git a/libsanitizer/ChangeLog b/libsanitizer/ChangeLog index 1b1b7acec02..7b2f1d1e00e 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. + 2016-09-16 Jakub Jelinek Backported from mainline diff --git a/libsanitizer/tsan/tsan_rtl.cc b/libsanitizer/tsan/tsan_rtl.cc index 4fceca6f41f..94cf985150e 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 !defined(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); -- cgit v1.2.1