| Message ID | 1588775643-18037-3-git-send-email-vbadigan@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | CQE fixes | expand |
On 6/05/20 5:34 pm, Veerabhadrarao Badiganti 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> # 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); > + } This looks good, but I think there needs to be another change also. I will send a patch for that, but in the meantime maybe you could straighten up the code flow through the spinlock e.g. spin_lock_irqsave(&mq->lock, flags); ignore = mq->recovery_needed || !mq->use_cqe || host->hsq_enabled; spin_unlock_irqrestore(&mq->lock, flags); return ignore ? BLK_EH_RESET_TIMER : mmc_cqe_timed_out(req); And add a fixes tag. > > return ret; > } >
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; }