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blk-iocost: ioc_pd_free() shouldn't assume irq disabled 

ioc_pd_free() grabs irq-safe ioc->lock without ensuring that irq is disabled
when it can be called with irq disabled or enabled. This has a small chance
of causing A-A deadlocks and triggers lockdep splats. Use irqsave operations
instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 7caa47151a ("blkcg: implement blk-iocost")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
zero-sugar-mainline-defconfig
Tejun Heo 2020-09-01 14:52:31 -04:00 committed by Jens Axboe
parent 08fc1ab6d7
commit 5aeac7c4b1
1 changed files with 3 additions and 2 deletions
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5
block/blk-iocost.c
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@ -2092,14 +2092,15 @@ static void ioc_pd_free(struct blkg_policy_data *pd)
{
struct ioc_gq *iocg = pd_to_iocg(pd);
struct ioc *ioc = iocg->ioc;
unsigned long flags;
if (ioc) {
spin_lock(&ioc->lock);
spin_lock_irqsave(&ioc->lock, flags);
if (!list_empty(&iocg->active_list)) {
propagate_active_weight(iocg, 0, 0);
list_del_init(&iocg->active_list);
}
spin_unlock(&ioc->lock);
spin_unlock_irqrestore(&ioc->lock, flags);
hrtimer_cancel(&iocg->waitq_timer);
hrtimer_cancel(&iocg->delay_timer);