[v3,2/2] block: fix blktrace debugfs entries leakage

Commit Message

Yu Kuai June 8, 2023, 2:41 a.m. UTC

From: Yu Kuai <[e-mail]>

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 <[e-mail]>
---
 block/genhd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Christoph Hellwig June 8, 2023, 6:13 a.m. UTC | #1

Looks good (at least for now, I think the SG_IO support on /dev/sg
really needs to go away or be completely separate from the disk one).

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

diff --git a/block/genhd.c b/block/genhd.c
index 3537b7d7c484..134cb6eb8e91 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