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@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230202141956.2299521-1-gregkh@linuxfoundation.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a66cff5..a5b35bc 100644 (file)
--- 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) {
         * 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);
        }
        } else {
                debugfs_remove(bt->dir);
        }