From e24721e441a7c640e4e7b2b63c23c06d9a750880 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Fri, 11 Aug 2023 21:52:16 +0800 Subject: [PATCH] ublk: fix 'warn: variable dereferenced before check 'req'' from Smatch The added check of 'req_op(req) == REQ_OP_ZONE_APPEND' should have been done after the request is confirmed as valid. Actually here, the request should always been true, so add one WARN_ON_ONCE(!req), meantime move the zone_append check after checking the request. Cc: Andreas Hindborg Reported-by: Dan Carpenter Fixes: 29802d7ca33b ("ublk: enable zoned storage support") Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20230811135216.420404-1-ming.lei@redhat.com Signed-off-by: Jens Axboe --- drivers/block/ublk_drv.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 109a5b1..e85e075 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1397,11 +1397,13 @@ static void ublk_commit_completion(struct ublk_device *ub, /* find the io request and complete */ req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag); + if (WARN_ON_ONCE(unlikely(!req))) + return; if (req_op(req) == REQ_OP_ZONE_APPEND) req->__sector = ub_cmd->zone_append_lba; - if (req && likely(!blk_should_fake_timeout(req->q))) + if (likely(!blk_should_fake_timeout(req->q))) ublk_put_req_ref(ubq, req); } -- 2.7.4