mpm_event: use a mutex for ptrans' allocator to be safe with concurrent
creation and destruction of its subpools, like with mod_http2.
@@ -2096,6 +2096,7 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t * thd, void *dummy)
}
if (!listeners_disabled) {
void *csd = NULL;
+ apr_thread_mutex_t *mutex;
ap_listen_rec *lr = (ap_listen_rec *) pt->baton;
apr_pool_t *ptrans; /* Pool for per-transaction stuff */
ap_pop_pool(&ptrans, worker_queue_info);
@@ -2105,20 +2106,44 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t * thd, void *dummy)
apr_allocator_t *allocator;
apr_allocator_create(&allocator);
- apr_allocator_max_free_set(allocator,
- ap_max_mem_free);
+ apr_allocator_max_free_set(allocator, ap_max_mem_free);
apr_pool_create_ex(&ptrans, pconf, NULL, allocator);
- apr_allocator_owner_set(allocator, ptrans);
if (ptrans == NULL) {
ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
ap_server_conf, APLOGNO(03097)
"Failed to create transaction pool");
+ apr_allocator_destroy(allocator);
signal_threads(ST_GRACEFUL);
return NULL;
}
+ apr_allocator_owner_set(allocator, ptrans);
}
apr_pool_tag(ptrans, "transaction");
+ /* We need a mutex in the allocator to synchronize ptrans'
+ * children creations/destructions, but this mutex ought to
+ * live in ptrans itself to avoid leaks, hence it's cleared
+ * in ap_push_pool(). We could recycle some pconf's mutexes
+ * like we do for ptrans subpools, but that'd need another
+ * synchronization mechanism, whereas creating a pthread
+ * mutex (unix here!) is really as simple/fast as a static
+ * PTHREAD_MUTEX_INIT assignment, so let's not bother and
+ * create the mutex for each ptrans (recycled or not).
+ */
+ rc = apr_thread_mutex_create(&mutex,
+ APR_THREAD_MUTEX_DEFAULT,
+ ptrans);
+ if (rc != APR_SUCCESS) {
+ ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
+ ap_server_conf, APLOGNO()
+ "Failed to create transaction pool mutex");
+ ap_push_pool(worker_queue_info, ptrans);
+ signal_threads(ST_GRACEFUL);
+ return NULL;
+ }
+ apr_allocator_mutex_set(apr_pool_allocator_get(ptrans),
+ mutex);
+
get_worker(&have_idle_worker, 1, &workers_were_busy);
rc = lr->accept_func(&csd, lr, ptrans);
