From: Christoph Hellwig <hch@xxxxxx> Subject: sched/wait: assert the wait_queue_head lock is held in __wake_up_common Better ensure we actually hold the lock using lockdep than just commenting on it. Due to the various exported _locked interfaces it is far too easy to get the locking wrong. Link: http://lkml.kernel.org/r/20171214152344.6880-4-hch@xxxxxx Signed-off-by: Christoph Hellwig <hch@xxxxxx> Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Jason Baron <jbaron@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/sched/wait.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/sched/wait.c~sched-wait-assert-the-wait_queue_head-lock-is-held-in-__wake_up_common +++ a/kernel/sched/wait.c @@ -69,6 +69,8 @@ static int __wake_up_common(struct wait_ wait_queue_entry_t *curr, *next; int cnt = 0; + lockdep_assert_held(&wq_head->lock); + if (bookmark && (bookmark->flags & WQ_FLAG_BOOKMARK)) { curr = list_next_entry(bookmark, entry); _
