diff options
Diffstat (limited to 'server/mpm/worker/fdqueue.c')
| -rw-r--r-- | server/mpm/worker/fdqueue.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/server/mpm/worker/fdqueue.c b/server/mpm/worker/fdqueue.c index d46dd536..dfbe8c47 100644 --- a/server/mpm/worker/fdqueue.c +++ b/server/mpm/worker/fdqueue.c @@ -155,7 +155,15 @@ apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t *queue_info, * region, one of two things may have happened: * - If the idle worker count is still zero, the * workers are all still busy, so it's safe to - * block on a condition variable. + * block on a condition variable, BUT + * we need to check for idle worker count again + * when we are signaled since it can happen that + * we are signaled by a worker thread that went idle + * but received a context switch before it could + * tell us. If it does signal us later once it is on + * CPU again there might be no idle worker left. + * See + * https://issues.apache.org/bugzilla/show_bug.cgi?id=45605#c4 * - If the idle worker count is nonzero, then a * worker has become idle since the first check * of queue_info->idlers above. It's possible @@ -166,7 +174,7 @@ apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t *queue_info, * now nonzero, it's safe for this function to * return immediately. */ - if (queue_info->idlers == 0) { + while (queue_info->idlers == 0) { rv = apr_thread_cond_wait(queue_info->wait_for_idler, queue_info->idlers_mutex); if (rv != APR_SUCCESS) { |