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: 7caa47151ab2 ("blkcg: implement blk-iocost") Cc: stable@vger.kernel.org # v5.4+ --- block/blk-iocost.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 413e0b5c8e6b..d37b55db2409 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -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);