| Message ID | 1588868135-31783-1-git-send-email-vbadigan@codeaurora.org |
|---|---|
| State | New |
| Headers | show |
| Series | [V2] mmc: core: Fix recursive locking issue in CQE recovery path | expand |
On Thu, 7 May 2020 at 18:15, Veerabhadrarao Badiganti <vbadigan@codeaurora.org> wrote: > > 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> > Fixes: 1e8e55b67030 ("mmc: block: Add CQE support") > Suggested-by: Sahitya Tummala <stummala@codeaurora.org> > Signed-off-by: Sarthak Garg <sartgarg@codeaurora.org> Applied for fixes, thanks! Kind regards Uffe > --- > drivers/mmc/core/queue.c | 13 ++++--------- > 1 file changed, 4 insertions(+), 9 deletions(-) > > diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c > index 25bee3d..b5fd3bc 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) */ > @@ -127,18 +127,13 @@ static enum blk_eh_timer_return mmc_mq_timed_out(struct request *req, > struct mmc_card *card = mq->card; > struct mmc_host *host = card->host; > unsigned long flags; > - int ret; > + bool ignore_tout; > > spin_lock_irqsave(&mq->lock, flags); > - > - if (mq->recovery_needed || !mq->use_cqe || host->hsq_enabled) > - ret = BLK_EH_RESET_TIMER; > - else > - ret = mmc_cqe_timed_out(req); > - > + ignore_tout = mq->recovery_needed || !mq->use_cqe || host->hsq_enabled; > spin_unlock_irqrestore(&mq->lock, flags); > > - return ret; > + return ignore_tout ? BLK_EH_RESET_TIMER : mmc_cqe_timed_out(req); > } > > static void mmc_mq_recovery_handler(struct work_struct *work) > -- > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc., is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c index 25bee3d..b5fd3bc 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) */ @@ -127,18 +127,13 @@ static enum blk_eh_timer_return mmc_mq_timed_out(struct request *req, struct mmc_card *card = mq->card; struct mmc_host *host = card->host; unsigned long flags; - int ret; + bool ignore_tout; spin_lock_irqsave(&mq->lock, flags); - - if (mq->recovery_needed || !mq->use_cqe || host->hsq_enabled) - ret = BLK_EH_RESET_TIMER; - else - ret = mmc_cqe_timed_out(req); - + ignore_tout = mq->recovery_needed || !mq->use_cqe || host->hsq_enabled; spin_unlock_irqrestore(&mq->lock, flags); - return ret; + return ignore_tout ? BLK_EH_RESET_TIMER : mmc_cqe_timed_out(req); } static void mmc_mq_recovery_handler(struct work_struct *work)