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| author | Maxim Dounin <mdounin@mdounin.ru> | 2016-04-19 17:18:28 +0300 |
|---|---|---|
| committer | Maxim Dounin <mdounin@mdounin.ru> | 2016-04-19 17:18:28 +0300 |
| commit | eeb72127cf4b86cb57f53e1f4702bbd1edd1a04a (patch) | |
| tree | de1673636b459bd5f057c4c90a25ff1ebaceb24b | |
| parent | eb38cbda2fcf318b9e1f2e463705658c286ec04e (diff) | |
| download | nginx-eeb72127cf4b86cb57f53e1f4702bbd1edd1a04a.tar.gz | |
Thread pools: memory barriers in task completion notifications.
The ngx_thread_pool_done object isn't volatile, and at least some
compilers assume that it is permitted to reorder modifications of
volatile and non-volatile objects. Added appropriate ngx_memory_barrier()
calls to make sure all modifications will happen before the lock is released.
Reported by Mindaugas Rasiukevicius,
http://mailman.nginx.org/pipermail/nginx-devel/2016-April/008160.html.
| -rw-r--r-- | src/core/ngx_thread_pool.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/core/ngx_thread_pool.c b/src/core/ngx_thread_pool.c index 03530851a..f3655aa0b 100644 --- a/src/core/ngx_thread_pool.c +++ b/src/core/ngx_thread_pool.c @@ -345,6 +345,8 @@ ngx_thread_pool_cycle(void *data) *ngx_thread_pool_done.last = task; ngx_thread_pool_done.last = &task->next; + ngx_memory_barrier(); + ngx_unlock(&ngx_thread_pool_done_lock); (void) ngx_notify(ngx_thread_pool_handler); @@ -366,6 +368,8 @@ ngx_thread_pool_handler(ngx_event_t *ev) ngx_thread_pool_done.first = NULL; ngx_thread_pool_done.last = &ngx_thread_pool_done.first; + ngx_memory_barrier(); + ngx_unlock(&ngx_thread_pool_done_lock); while (task) { |