[PATCH 6.4 041/800] block: fix blktrace debugfs entries leakage

Greg Kroah-Hartman
2023-07-16T19:54:44Z

From: Yu Kuai <yukuai3@huawei.com>

[ Upstream commit dd7de3704af9989b780693d51eaea49a665bd9c2 ]

Commit 99d055b4fd4b ("block: remove per-disk debugfs files in
blk_unregister_queue") moves blk_trace_shutdown() from
blk_release_queue() to blk_unregister_queue(), this is safe if blktrace
is created through sysfs, however, there is a regression in corner
case.

blktrace can still be enabled after del_gendisk() through ioctl if
the disk is opened before del_gendisk(), and if blktrace is not shutdown
through ioctl before closing the disk, debugfs entries will be leaked.

Fix this problem by shutdown blktrace in disk_release(), this is safe
because blk_trace_remove() is reentrant.

Fixes: 99d055b4fd4b ("block: remove per-disk debugfs files in blk_unregister_queue")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230610022003.2557284-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/genhd.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index 1cb489b927d50..bb895397e9385 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -25,8 +25,9 @@
#include <linux/pm_runtime.h>
#include <linux/badblocks.h>
#include <linux/part_stat.h>
-#include "blk-throttle.h"
+#include <linux/blktrace_api.h>

+#include "blk-throttle.h"
#include "blk.h"
#include "blk-mq-sched.h"
#include "blk-rq-qos.h"
@@ -1171,6 +1172,8 @@ static void disk_release(struct device *dev)
might_sleep();
WARN_ON_ONCE(disk_live(disk));

+ blk_trace_remove(disk->queue);
+
/*
* To undo the all initialization from blk_mq_init_allocated_queue in
* case of a probe failure where add_disk is never called we have to
--
2.39.2