From e8271201462710dbbaa0448b768428606724ca90 Mon Sep 17 00:00:00 2001 From: Mike Krinkin Date: Tue, 15 Dec 2015 12:56:40 +0300 Subject: [PATCH] null_blk: fix use-after-free error blk_end_request_all may free request, so we need to save request_queue pointer before blk_end_request_all call. The problem was introduced in commit cf8ecc5a8455266f8d51 ("null_blk: guarantee device restart in all irq modes") and causes general protection fault with slab poisoning enabled. Fixes: cf8ecc5a8455266f8d51 ("null_blk: guarantee device restart in all irq modes") Signed-off-by: Mike Krinkin Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- drivers/block/null_blk.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index 8162475..a428e4e 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -219,6 +219,9 @@ static void end_cmd(struct nullb_cmd *cmd) { struct request_queue *q = NULL; + if (cmd->rq) + q = cmd->rq->q; + switch (queue_mode) { case NULL_Q_MQ: blk_mq_end_request(cmd->rq, 0); @@ -232,9 +235,6 @@ static void end_cmd(struct nullb_cmd *cmd) goto free_cmd; } - if (cmd->rq) - q = cmd->rq->q; - /* Restart queue if needed, as we are freeing a tag */ if (q && !q->mq_ops && blk_queue_stopped(q)) { unsigned long flags; -- 2.7.4