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No direct upstream commit exists for this issue. It was fixed in 5.18 as part of a larger rework of the completion side. io_commit_cqring() writes the CQ ring tail to make it visible, but it also kicks off any deferred work we have. A ring setup with IOPOLL does not need any locking around the CQ ring updates, as we're always under the ctx uring_lock. But if we have deferred work that needs processing, then io_queue_deferred() assumes that the completion_lock is held, as it is for !IOPOLL. Add a lockdep assertion to check and document this fact, and have io_iopoll_complete() check if we have deferred work and run that separately with the appropriate lock grabbed. Cc: stable@vger.kernel.org # 5.10, 5.15 Reported-by: dghost david <daviduniverse18@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>