From 5b8c9f7a26ee9b1c447af7998a59127d240e9ec4 Mon Sep 17 00:00:00 2001 From: Yann Ylavic Date: Mon, 20 Feb 2017 22:49:05 +0000 Subject: [PATCH] mpm_worker: follow up to r1783755. Use a mutex for ptrans' allocator to be safe with concurrent creation and destruction of its subpools, like with mod_http2. git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1783808 13f79535-47bb-0310-9956-ffa450edef68 --- docs/log-message-tags/next-number | 2 +- server/mpm/worker/worker.c | 27 +++++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 1 deletion(-) diff --git a/docs/log-message-tags/next-number b/docs/log-message-tags/next-number index e7ea1abc3c..8a0934b514 100644 --- a/docs/log-message-tags/next-number +++ b/docs/log-message-tags/next-number @@ -1 +1 @@ -10019 +10020 diff --git a/server/mpm/worker/worker.c b/server/mpm/worker/worker.c index ed062b2abe..e3452c99a3 100644 --- a/server/mpm/worker/worker.c +++ b/server/mpm/worker/worker.c @@ -833,6 +833,8 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t *thd, void * dummy) } /* if/else */ if (!listener_may_exit) { + apr_thread_mutex_t *mutex; + if (ptrans == NULL) { /* we can't use a recycled transaction pool this time. * create a new transaction pool */ @@ -844,6 +846,31 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t *thd, void * dummy) 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). + */ + rv = apr_thread_mutex_create(&mutex, + APR_THREAD_MUTEX_DEFAULT, + ptrans); + if (rv != APR_SUCCESS) { + ap_log_error(APLOG_MARK, APLOG_CRIT, rv, + ap_server_conf, APLOGNO(10019) + "Failed to create transaction pool mutex"); + resource_shortage = 1; + signal_threads(ST_GRACEFUL); + return NULL; + } + apr_allocator_mutex_set(apr_pool_allocator_get(ptrans), + mutex); + rv = lr->accept_func(&csd, lr, ptrans); /* later we trash rv and rely on csd to indicate success/failure */ AP_DEBUG_ASSERT(rv == APR_SUCCESS || !csd); -- 2.40.0