53 lines
1.8 KiB
Diff
53 lines
1.8 KiB
Diff
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From 1eefbe38f6a7266e1489765317f4e89489856fc1 Mon Sep 17 00:00:00 2001
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From: Dan Rosen <mergeconflict@google.com>
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Date: Wed, 17 Apr 2019 15:44:59 -0400
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Subject: [PATCH 2/2] evwatch: fix race condition
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There was a race between event_base_loop and evwatch_new (adding a
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prepare/check watcher while iterating over the watcher list). Only
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release the mutex immediately before invoking each watcher callback,
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and reacquire it immediately afterwards (same as is done for normal
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event handlers).
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---
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event.c | 14 ++++++++------
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1 file changed, 8 insertions(+), 6 deletions(-)
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diff --git a/event.c b/event.c
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index 5e41ae04..c6eb175c 100644
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--- a/event.c
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+++ b/event.c
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@@ -2012,11 +2012,12 @@ event_base_loop(struct event_base *base, int flags)
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event_queue_make_later_events_active(base);
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/* Invoke prepare watchers before polling for events */
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- EVBASE_RELEASE_LOCK(base, th_base_lock);
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prepare_info.timeout = tv_p;
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- TAILQ_FOREACH(watcher, &base->watchers[EVWATCH_PREPARE], next)
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+ TAILQ_FOREACH(watcher, &base->watchers[EVWATCH_PREPARE], next) {
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+ EVBASE_RELEASE_LOCK(base, th_base_lock);
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(*watcher->callback.prepare)(watcher, &prepare_info, watcher->arg);
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- EVBASE_ACQUIRE_LOCK(base, th_base_lock);
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+ EVBASE_ACQUIRE_LOCK(base, th_base_lock);
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+ }
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clear_time_cache(base);
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@@ -2033,10 +2034,11 @@ event_base_loop(struct event_base *base, int flags)
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/* Invoke check watchers after polling for events, and before
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* processing them */
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- EVBASE_RELEASE_LOCK(base, th_base_lock);
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- TAILQ_FOREACH(watcher, &base->watchers[EVWATCH_CHECK], next)
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+ TAILQ_FOREACH(watcher, &base->watchers[EVWATCH_CHECK], next) {
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+ EVBASE_RELEASE_LOCK(base, th_base_lock);
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(*watcher->callback.check)(watcher, &check_info, watcher->arg);
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- EVBASE_ACQUIRE_LOCK(base, th_base_lock);
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+ EVBASE_ACQUIRE_LOCK(base, th_base_lock);
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+ }
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timeout_process(base);
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--
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2.23.0
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