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authorJeff Moyer <jmoyer@redhat.com>2013-12-03 14:23:00 -0700
committerJens Axboe <axboe@kernel.dk>2013-12-03 14:24:28 -0700
commit959a35f13eb785f982d79b1aaa75872d05c821da (patch)
treecf6d053aee1a645f5ec9fc8e81d5f153b5a8692d /block
parente345d767f6530ec9cb0aabab7ea248072a9c6975 (diff)
downloadlinux-959a35f13eb785f982d79b1aaa75872d05c821da.tar.gz
blk-mq: fix dereference of rq->mq_ctx if allocation fails
If __GFP_WAIT isn't set and we fail allocating, when we go to drop the reference on the ctx, we will attempt to dereference the NULL rq. Fix that. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index cdc629cf075..70fd6f99660 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -202,10 +202,12 @@ static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,
if (rq) {
blk_mq_rq_ctx_init(q, ctx, rq, rw);
break;
- } else if (!(gfp & __GFP_WAIT))
- break;
+ }
blk_mq_put_ctx(ctx);
+ if (!(gfp & __GFP_WAIT))
+ break;
+
__blk_mq_run_hw_queue(hctx);
blk_mq_wait_for_tags(hctx->tags);
} while (1);
@@ -222,7 +224,8 @@ struct request *blk_mq_alloc_request(struct request_queue *q, int rw,
return NULL;
rq = blk_mq_alloc_request_pinned(q, rw, gfp, reserved);
- blk_mq_put_ctx(rq->mq_ctx);
+ if (rq)
+ blk_mq_put_ctx(rq->mq_ctx);
return rq;
}
@@ -235,7 +238,8 @@ struct request *blk_mq_alloc_reserved_request(struct request_queue *q, int rw,
return NULL;
rq = blk_mq_alloc_request_pinned(q, rw, gfp, true);
- blk_mq_put_ctx(rq->mq_ctx);
+ if (rq)
+ blk_mq_put_ctx(rq->mq_ctx);
return rq;
}
EXPORT_SYMBOL(blk_mq_alloc_reserved_request);