Author: Maxim Ostapenko <m.ostapenko@partner.samsung.com>
Date: Fri Oct 28 06:49:53 2016 +0000
[asan/lsan] Avoid possible deadlock in dynamic ASan runtime thread initialization.
There is possible deadlock in dynamic ASan runtime when we dlopen() shared lib
which creates a thread at the global initialization stage. The scenario:
1) dlopen grabs a GI_pthread_mutex_lock in main thread.
2) main thread calls pthread_create, ASan intercepts it, calls real pthread_create
and waits for the second thread to be "fully initialized".
3) Newly created thread tries to access a thread local disable_counter in LSan
(to complete its "full initialization") and hangs in tls_get_addr_tail, because
it also tries to acquire GI_pthread_mutex_lock.
The issue is reproducible on relative recent Glibc versions e.g. 2.23.
Differential Revision: https://reviews.llvm.org/D26028
Change-Id: I0ed82cb81dd9d37d0be96ece03b667090b72164a
// also to protect the global list of root regions.
BlockingMutex global_mutex(LINKER_INITIALIZED);
+__attribute__((tls_model("initial-exec")))
THREADLOCAL int disable_counter;
bool DisabledInThisThread() { return disable_counter > 0; }