From: Wenwen Wang <wang6495@umn.edu>
To: Wenwen Wang <wenwen@cs.uga.edu>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org (open list:BLOCK LAYER),
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] blk-mq: fix a memory leak bug
Date: Sun, 14 Jul 2019 02:03:21 -0500 [thread overview]
Message-ID: <1563087801-7373-1-git-send-email-wang6495@umn.edu> (raw)
From: Wenwen Wang <wenwen@cs.uga.edu>
In blk_mq_init_allocated_queue(), a kernel buffer is allocated through
kcalloc_node() to hold hardware dispatch queues in the request queue 'q',
i.e., 'q->queue_hw_ctx'. Later on, if the blk-mq device has no scheduler
set, a scheduler will be initialized through elevator_init_mq(). If this
initialization fails, blk_mq_init_allocated_queue() needs to be terminated
with an error code returned to indicate this failure. However, the
allocated buffer is not freed on this execution path, leading to a memory
leak bug. Moreover, the required cleanup work is also missed on this path.
To fix the above issues, free the allocated buffer and invoke the cleanup
functions.
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
---
block/blk-mq.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index e5ef40c..04fe077 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2845,6 +2845,8 @@ static unsigned int nr_hw_queues(struct blk_mq_tag_set *set)
struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
struct request_queue *q)
{
+ int ret = -ENOMEM;
+
/* mark the queue as mq asap */
q->mq_ops = set->ops;
@@ -2906,11 +2908,9 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
blk_mq_map_swqueue(q);
if (!(set->flags & BLK_MQ_F_NO_SCHED)) {
- int ret;
-
ret = elevator_init_mq(q);
if (ret)
- return ERR_PTR(ret);
+ goto err_hctxs;
}
return q;
@@ -2924,7 +2924,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
q->poll_cb = NULL;
err_exit:
q->mq_ops = NULL;
- return ERR_PTR(-ENOMEM);
+ return ERR_PTR(ret);
}
EXPORT_SYMBOL(blk_mq_init_allocated_queue);
--
2.7.4
next reply other threads:[~2019-07-14 7:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-14 7:03 Wenwen Wang [this message]
2019-07-15 1:25 ` [PATCH] blk-mq: fix a memory leak bug Ming Lei
2019-07-15 4:57 ` Wenwen Wang
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