Messages in this thread Patch in this message | | | From | Johannes Berg <> | Subject | [PATCH 2/2] workqueue: create lockdep dependency in flush_work() | Date | Tue, 21 Aug 2018 14:03:17 +0200 |
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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
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