diff options
| -rw-r--r-- | winsup/cygwin/ChangeLog | 5 | ||||
| -rw-r--r-- | winsup/cygwin/thread.cc | 14 |
2 files changed, 17 insertions, 2 deletions
diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog index ec7ff13da..7b3d56d9a 100644 --- a/winsup/cygwin/ChangeLog +++ b/winsup/cygwin/ChangeLog @@ -1,5 +1,10 @@ 2012-05-23 Corinna Vinschen <corinna@vinschen.de> + * thread.cc (pthread::precreate): Make sure mutex is recursive. + Explain why. + +2012-05-23 Corinna Vinschen <corinna@vinschen.de> + * thread.cc (pthread::pop_cleanup_handler): Move setting the cancelstate to PTHREAD_CANCEL_DISABLE from here... (pthread::pop_all_cleanup_handlers): ...to here, otherwise any explicit diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc index bb38ff3ed..7a914b281 100644 --- a/winsup/cygwin/thread.cc +++ b/winsup/cygwin/thread.cc @@ -431,8 +431,18 @@ pthread::precreate (pthread_attr *newattr) magic = 0; return; } - /* Change the mutex type to NORMAL to speed up mutex operations */ - mutex.set_type (PTHREAD_MUTEX_NORMAL); + /* This mutex MUST be recursive. Consider the following scenario: + - The thread installs a cleanup handler. + - The cleanup handler calls a function which itself installs a + cleanup handler. + - pthread_cancel is called for this thread. + - The thread's cleanup handler is called under mutex lock condition. + - The cleanup handler calls the subsequent function with cleanup handler. + - The function runs to completion, so it calls pthread_cleanup_pop. + - pthread_cleanup_pop calls pthread::pop_cleanup_handler which will again + try to lock the mutex. + - Deadlock. */ + mutex.set_type (PTHREAD_MUTEX_RECURSIVE); if (!create_cancel_event ()) magic = 0; } |