2023-02-02 14:20:05

by Greg Kroah-Hartman

Subject: [PATCH] trace/blktrace: fix memory leak with using debugfs_lookup()

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: Jens Axboe <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/trace/blktrace.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 918a7d12df8f..5743be559415 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -320,8 +320,8 @@ static void blk_trace_free(struct request_queue *q, struct blk_trace *bt)
* under 'q->debugfs_dir', thus lookup and remove them.
*/
if (!bt->dir) {
- debugfs_remove(debugfs_lookup("dropped", q->debugfs_dir));
- debugfs_remove(debugfs_lookup("msg", q->debugfs_dir));
+ debugfs_lookup_and_remove("dropped", q->debugfs_dir);
+ debugfs_lookup_and_remove("msg", q->debugfs_dir);
} else {
debugfs_remove(bt->dir);
}
--
2.39.1

2023-02-04 23:17:12

by Bart Van Assche

Subject: Re: [PATCH] trace/blktrace: fix memory leak with using debugfs_lookup()

On 2/2/23 06:19, Greg Kroah-Hartman wrote:
> When calling debugfs_lookup() the result must have dput() called on it,
> otherwise the memory will leak over time. To make things simpler, just
> call debugfs_lookup_and_remove() instead which handles all of the logic
> at once.
>
> Cc: Jens Axboe <[email protected]>
> Cc: Steven Rostedt <[email protected]>
> Cc: Masami Hiramatsu <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Greg Kroah-Hartman <[email protected]>
> ---
> kernel/trace/blktrace.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index 918a7d12df8f..5743be559415 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -320,8 +320,8 @@ static void blk_trace_free(struct request_queue *q, struct blk_trace *bt)
> * under 'q->debugfs_dir', thus lookup and remove them.
> */
> if (!bt->dir) {
> - debugfs_remove(debugfs_lookup("dropped", q->debugfs_dir));
> - debugfs_remove(debugfs_lookup("msg", q->debugfs_dir));
> + debugfs_lookup_and_remove("dropped", q->debugfs_dir);
> + debugfs_lookup_and_remove("msg", q->debugfs_dir);
> } else {
> debugfs_remove(bt->dir);
> }

Reviewed-by: Bart Van Assche <[email protected]>

2023-02-06 16:29:56

by Jens Axboe

Subject: Re: [PATCH] trace/blktrace: fix memory leak with using debugfs_lookup()

On Thu, 02 Feb 2023 15:19:56 +0100, Greg Kroah-Hartman wrote:
> When calling debugfs_lookup() the result must have dput() called on it,
> otherwise the memory will leak over time. To make things simpler, just
> call debugfs_lookup_and_remove() instead which handles all of the logic
> at once.
>
>

Applied, thanks!

[1/1] trace/blktrace: fix memory leak with using debugfs_lookup()
commit: 83e8864fee26f63a7435e941b7c36a20fd6fe93e

Best regards,
--
Jens Axboe