From: Sarthak Garg sartgarg@codeaurora.org
Consider the following stack trace
-001|raw_spin_lock_irqsave -002|mmc_blk_cqe_complete_rq -003|__blk_mq_complete_request(inline) -003|blk_mq_complete_request(rq) -004|mmc_cqe_timed_out(inline) -004|mmc_mq_timed_out
mmc_mq_timed_out acquires the queue_lock for the first time. The mmc_blk_cqe_complete_rq function also tries to acquire the same queue lock resulting in recursive locking where the task is spinning for the same lock which it has already acquired leading to watchdog bark.
Fix this issue with the lock only for the required critical section.
Cc: stable@vger.kernel.org # v4.19+ Suggested-by: Sahitya Tummala stummala@codeaurora.org Signed-off-by: Sarthak Garg sartgarg@codeaurora.org --- drivers/mmc/core/queue.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c index 25bee3d..72bef39 100644 --- a/drivers/mmc/core/queue.c +++ b/drivers/mmc/core/queue.c @@ -107,7 +107,7 @@ static enum blk_eh_timer_return mmc_cqe_timed_out(struct request *req) case MMC_ISSUE_DCMD: if (host->cqe_ops->cqe_timeout(host, mrq, &recovery_needed)) { if (recovery_needed) - __mmc_cqe_recovery_notifier(mq); + mmc_cqe_recovery_notifier(mrq); return BLK_EH_RESET_TIMER; } /* No timeout (XXX: huh? comment doesn't make much sense) */ @@ -131,12 +131,13 @@ static enum blk_eh_timer_return mmc_mq_timed_out(struct request *req,
spin_lock_irqsave(&mq->lock, flags);
- if (mq->recovery_needed || !mq->use_cqe || host->hsq_enabled) + if (mq->recovery_needed || !mq->use_cqe || host->hsq_enabled) { ret = BLK_EH_RESET_TIMER; - else + spin_unlock_irqrestore(&mq->lock, flags); + } else { + spin_unlock_irqrestore(&mq->lock, flags); ret = mmc_cqe_timed_out(req); - - spin_unlock_irqrestore(&mq->lock, flags); + }
return ret; }