提交 5fd7a84a 编写于 作者: M Ming Lei 提交者: Jens Axboe

blk-mq: protect q->elevator by ->sysfs_lock in blk_mq_elv_switch_none

elevator can be tore down by sysfs switch interface or disk release, so
hold ->sysfs_lock before referring to q->elevator, then potential
use-after-free can be avoided.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220616014401.817001-2-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>
上级 14dc7a18
......@@ -4440,12 +4440,14 @@ static bool blk_mq_elv_switch_none(struct list_head *head,
if (!qe)
return false;
/* q->elevator needs protection from ->sysfs_lock */
mutex_lock(&q->sysfs_lock);
INIT_LIST_HEAD(&qe->node);
qe->q = q;
qe->type = q->elevator->type;
list_add(&qe->node, head);
mutex_lock(&q->sysfs_lock);
/*
* After elevator_switch_mq, the previous elevator_queue will be
* released by elevator_release. The reference of the io scheduler
......
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