From 190b02ed79e08983bf62d47c05945c1b06a3d7d5 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 9 Jun 2018 06:37:14 -0600 Subject: [PATCH] block: fix use-after-free in block flush handling A recent commit reused the original request flags for the flush queue handling. However, for some of the kick flush cases, the original request was already completed. This caused a use after free, if blk-mq wasn't used. Fixes: 84fca1b0c461 ("block: pass failfast and driver-specific flags to flush requests") Reported-by: Dmitry Vyukov Signed-off-by: Jens Axboe --- block/blk-flush.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/blk-flush.c b/block/blk-flush.c index 058abdb50f31..ce41f666de3e 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -169,9 +169,11 @@ static bool blk_flush_complete_seq(struct request *rq, struct request_queue *q = rq->q; struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx]; bool queued = false, kicked; + unsigned int cmd_flags; BUG_ON(rq->flush.seq & seq); rq->flush.seq |= seq; + cmd_flags = rq->cmd_flags; if (likely(!error)) seq = blk_flush_cur_seq(rq); @@ -212,7 +214,7 @@ static bool blk_flush_complete_seq(struct request *rq, BUG(); } - kicked = blk_kick_flush(q, fq, rq->cmd_flags); + kicked = blk_kick_flush(q, fq, cmd_flags); return kicked | queued; } -- 2.30.2