[compiler-rt] r268238 - [sanitizer] Don't reuse the main thread in ThreadRegistry

[Kuba Brecka via llvm-commits]

Author: kuba.brecka
Date: Mon May  2 10:06:08 2016
New Revision: 268238

URL: http://llvm.org/viewvc/llvm-project?rev=268238&view=rev
Log:
[sanitizer] Don't reuse the main thread in ThreadRegistry

There is a hard-to-reproduce crash happening on OS X that involves terminating the main thread (dispatch_main does that, see discussion at http://reviews.llvm.org/D18496) and later reusing the main thread's ThreadContext. This patch disables reuse of the main thread. I believe this problem exists only on OS X, because on other systems the main thread cannot be terminated without exiting the process.

Differential Revision: http://reviews.llvm.org/D19722


Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_thread_registry.cc

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_thread_registry.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_thread_registry.cc?rev=268238&r1=268237&r2=268238&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_thread_registry.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_thread_registry.cc Mon May  2 10:06:08 2016
@@ -277,6 +277,8 @@ void ThreadRegistry::StartThread(u32 tid
 }
 
 void ThreadRegistry::QuarantinePush(ThreadContextBase *tctx) {
+  if (tctx->tid == 0)
+    return;  // Don't reuse the main thread.  It's a special snowflake.
   dead_threads_.push_back(tctx);
   if (dead_threads_.size() <= thread_quarantine_size_)
     return;