Patch "trace/blktrace: fix memory leak with using debugfs_lookup()" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    trace/blktrace: fix memory leak with using debugfs_lookup()

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     trace-blktrace-fix-memory-leak-with-using-debugfs_lo.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit cb3a7f36536a854c4814f46eb0b2aca9b9460f71
Author: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Date:   Thu Feb 2 15:19:56 2023 +0100

    trace/blktrace: fix memory leak with using debugfs_lookup()
    
    [ Upstream commit 83e8864fee26f63a7435e941b7c36a20fd6fe93e ]
    
    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 <axboe@xxxxxxxxx>
    Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
    Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
    Cc: linux-block@xxxxxxxxxxxxxxx
    Cc: linux-kernel@xxxxxxxxxxxxxxx
    Cc: linux-trace-kernel@xxxxxxxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
    Link: https://lore.kernel.org/r/20230202141956.2299521-1-gregkh@xxxxxxxxxxxxxxxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a66cff5a18579..a5b35bcfb0602 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);
 	}