From: Johannes Berg <johannes@sipsolutions.net>
To: Tejun Heo <tj@kernel.org>, Lai Jiangshan <jiangshanlai@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH 2/2] workqueue: create lockdep dependency in flush_work()
Date: Tue, 21 Aug 2018 14:03:17 +0200 [thread overview]
Message-ID: <20180821120317.4115-3-johannes@sipsolutions.net> (raw)
In-Reply-To: <20180821120317.4115-1-johannes@sipsolutions.net>
From: Johannes Berg <johannes.berg@intel.com>
In flush_work(), we need to create a lockdep dependency so that
the following scenario is appropriately tagged as a problem:
work_function()
{
mutex_lock(&mutex);
...
}
other_function()
{
mutex_lock(&mutex);
flush_work(&work); // or cancel_work_sync(&work);
}
This is a problem since the work might be running and be blocked
on trying to acquire the mutex.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
kernel/workqueue.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index a6c2b823f348..29d4d84ba512 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2852,6 +2852,11 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
might_sleep();
+ if (!from_cancel) {
+ lock_map_acquire(&work->lockdep_map);
+ lock_map_release(&work->lockdep_map);
+ }
+
local_irq_disable();
pool = get_work_pool(work);
if (!pool) {
--
2.14.4
next prev parent reply other threads:[~2018-08-21 12:38 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-21 12:03 [PATCH 0/2] workqueue lockdep limitations/bugs Johannes Berg
2018-08-21 12:03 ` [PATCH 1/2] workqueue: skip lockdep wq dependency in cancel_work_sync() Johannes Berg
2018-08-21 16:08 ` Tejun Heo
2018-08-21 17:18 ` Johannes Berg
2018-08-21 17:27 ` Tejun Heo
2018-08-21 17:30 ` Johannes Berg
2018-08-21 17:55 ` Tejun Heo
2018-08-21 19:20 ` Johannes Berg
2018-08-22 2:45 ` Byungchul Park
2018-08-22 4:02 ` Johannes Berg
2018-08-22 5:47 ` Byungchul Park
2018-08-22 7:07 ` Johannes Berg
2018-08-22 7:50 ` Byungchul Park
2018-08-22 8:02 ` Johannes Berg
2018-08-22 9:15 ` Byungchul Park
2018-08-22 9:42 ` Johannes Berg
2018-08-22 12:47 ` Byungchul Park
2018-08-21 12:03 ` Johannes Berg [this message]
2018-08-21 16:09 ` [PATCH 2/2] workqueue: create lockdep dependency in flush_work() Tejun Heo
2018-08-21 17:19 ` Johannes Berg
2018-08-21 16:00 ` [PATCH 0/2] workqueue lockdep limitations/bugs Tejun Heo
2018-08-21 17:15 ` Johannes Berg
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