Fix for pthread_setspecific (TLS and shutdown) problem

Some codes that use TLS fail intermittently because one thread tries to write
TLS values after the TLS key has been destroyed by another thread. This happens
when one thread executes library shutdown (and destroys TLS keys), while another
thread starts to execute the TLS key destructor routine. Before this change, the
kmp_init_runtime flag was checked before calling pthread_* TLS functions, but
this flag is set to FALSE later than the destruction of the TLS keys, which
leads to failure. The fix is to check kmp_init_gtid instead, as this flag is
unset *before* the destruction of TLS keys.

Differential Revision: http://reviews.llvm.org/D19022

llvm-svn: 266674

1 files changed, 9 insertions, 6 deletions

diff --git a/openmp/runtime/src/z_Linux_util.c b/openmp/runtime/src/z_Linux_util.c
index 16fc1c9ce98..1e7683d2402 100644
--- a/openmp/runtime/src/z_Linux_util.c
+++ b/openmp/runtime/src/z_Linux_util.c
@@ -1897,18 +1897,21 @@ __kmp_yield( int cond )
 void
 __kmp_gtid_set_specific( int gtid )
 {
-    int status;
-    KMP_ASSERT( __kmp_init_runtime );
-    status = pthread_setspecific( __kmp_gtid_threadprivate_key, (void*)(intptr_t)(gtid+1) );
-    KMP_CHECK_SYSFAIL( "pthread_setspecific", status );
+    if( __kmp_init_gtid ) {
+        int status;
+        status = pthread_setspecific( __kmp_gtid_threadprivate_key, (void*)(intptr_t)(gtid+1) );
+        KMP_CHECK_SYSFAIL( "pthread_setspecific", status );
+    } else {
+        KA_TRACE( 50, ("__kmp_gtid_set_specific: runtime shutdown, returning\n" ) );
+    }
 }
 
 int
 __kmp_gtid_get_specific()
 {
     int gtid;
-    if ( !__kmp_init_runtime ) {
-        KA_TRACE( 50, ("__kmp_get_specific: runtime shutdown, returning KMP_GTID_SHUTDOWN\n" ) );
+    if ( !__kmp_init_gtid ) {
+        KA_TRACE( 50, ("__kmp_gtid_get_specific: runtime shutdown, returning KMP_GTID_SHUTDOWN\n" ) );
         return KMP_GTID_SHUTDOWN;
     }
     gtid = (int)(size_t)pthread_getspecific( __kmp_gtid_threadprivate_key );