Mercurial > hg > nginx
changeset 6517:657e029bac28
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.
| author | Maxim Dounin <mdounin@mdounin.ru> |
|---|---|
| date | Tue, 19 Apr 2016 17:18:28 +0300 |
| parents | ab16126a06a0 |
| children | 7760b54d5458 |
| files | src/core/ngx_thread_pool.c |
| diffstat | 1 files changed, 4 insertions(+), 0 deletions(-) [+] |
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--- 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) {