[Openais] [PATCH 6/7] aisexec crash on exit
angus salkeld
angus.salkeld at alliedtelesis.co.nz
Tue Aug 19 11:55:00 PDT 2008
Cause:
As part of its exit procedure, ais cancels its worker thread then manually
processes any outstanding items that were still in the worker thread's queue.
The worker thread has a low priority so normally it does not execute any
further before ais finishes exiting, but if the main thread's exiting is
delayed for any reason, there is a chance the worker thread could execute and
try to process items which have already been processed and freed by the main
thread - often leading to the worker thread seeing NULL data and ultimately
causing a segmentation fault.
Fix:
Modified worker_thread_group_exit() so it does a pthread_join() after the
pthread_cancel() call, so that the worker thread always shuts down cleanly
before the main thread does its cleanup.
Author: Author: Mark McKinstry <mark.mckinstry at alliedtelesis.co.nz>
---
exec/wthread.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/exec/wthread.c b/exec/wthread.c
index 6a434fd..e97f917 100644
--- a/exec/wthread.c
+++ b/exec/wthread.c
@@ -183,6 +183,11 @@ void worker_thread_group_exit (
for (i = 0; i < worker_thread_group->threadcount; i++) {
pthread_cancel (worker_thread_group->threads[i].thread_id);
+
+ /* Wait for worker thread to exit gracefully before destroying
+ * mutexes and processing items in the queue etc.
+ */
+ pthread_join (worker_thread_group->threads[i].thread_id, NULL);
pthread_mutex_destroy (&worker_thread_group->threads[i].new_work_mutex);
pthread_cond_destroy (&worker_thread_group->threads[i].new_work_cond);
pthread_mutex_destroy (&worker_thread_group->threads[i].done_work_mutex);
--
1.5.6
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