Commit 190b02ed authored by Jens Axboe's avatar Jens Axboe
Browse files

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: 84fca1b0

 ("block: pass failfast and driver-specific flags to flush requests")
Reported-by: default avatarDmitry Vyukov <>
Signed-off-by: default avatarJens Axboe <>
parent 77016199
......@@ -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,
kicked = blk_kick_flush(q, fq, rq->cmd_flags);
kicked = blk_kick_flush(q, fq, cmd_flags);
return kicked | queued;
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