linux-kernel - [PATCH 5.17 073/298] blk-mq: dont touch ->tagset in blk_mq_get_sq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220613094927.162000910@linuxfoundation.org>
Date:   Mon, 13 Jun 2022 12:09:27 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, "yukuai (C)" <yukuai3@...wei.com>,
        Jan Kara <jack@...e.cz>, Ming Lei <ming.lei@...hat.com>,
        Jens Axboe <axboe@...nel.dk>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.17 073/298] blk-mq: dont touch ->tagset in blk_mq_get_sq_hctx

From: Ming Lei <ming.lei@...hat.com>

[ Upstream commit 5d05426e2d5fd7df8afc866b78c36b37b00188b7 ]

blk_mq_run_hw_queues() could be run when there isn't queued request and
after queue is cleaned up, at that time tagset is freed, because tagset
lifetime is covered by driver, and often freed after blk_cleanup_queue()
returns.

So don't touch ->tagset for figuring out current default hctx by the mapping
built in request queue, so use-after-free on tagset can be avoided. Meantime
this way should be fast than retrieving mapping from tagset.

Cc: "yukuai (C)" <yukuai3@...wei.com>
Cc: Jan Kara <jack@...e.cz>
Fixes: b6e68ee82585 ("blk-mq: Improve performance of non-mq IO schedulers with multiple HW queues")
Signed-off-by: Ming Lei <ming.lei@...hat.com>
Reviewed-by: Jan Kara <jack@...e.cz>
Link: https://lore.kernel.org/r/20220522122350.743103-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 block/blk-mq.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0aa20df31e36..6afe0cd128ac 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2114,8 +2114,7 @@ static bool blk_mq_has_sqsched(struct request_queue *q)
  */
 static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
 {
-	struct blk_mq_hw_ctx *hctx;
-
+	struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
 	/*
 	 * If the IO scheduler does not respect hardware queues when
 	 * dispatching, we just don't bother with multiple HW queues and
@@ -2123,8 +2122,8 @@ static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
 	 * just causes lock contention inside the scheduler and pointless cache
 	 * bouncing.
 	 */
-	hctx = blk_mq_map_queue_type(q, HCTX_TYPE_DEFAULT,
-				     raw_smp_processor_id());
+	struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, 0, ctx);
+
 	if (!blk_mq_hctx_stopped(hctx))
 		return hctx;
 	return NULL;
-- 
2.35.1