releases/6.15.8/fix-a-leak-in-fcntl_dirnotify.patch

From 931c12c717cdebea52a5d6010fc4bb1ad8e278de Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Sat, 12 Jul 2025 18:18:43 +0100
Subject: fix a leak in fcntl_dirnotify()

From: Al Viro <viro@zeniv.linux.org.uk>

[ Upstream commit fdfe0133473a528e3f5da69c35419ce6711d6b89 ]

[into #fixes, unless somebody objects]

Lifetime of new_dn_mark is controlled by that of its ->fsn_mark,
pointed to by new_fsn_mark.  Unfortunately, a failure exit had
been inserted between the allocation of new_dn_mark and the
call of fsnotify_init_mark(), ending up with a leak.

Fixes: 1934b212615d "file: reclaim 24 bytes from f_owner"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/20250712171843.GB1880847@ZenIV
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/notify/dnotify/dnotify.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c
index c4cdaf5fa7eda..9fb73bafd41d2 100644
--- a/fs/notify/dnotify/dnotify.c
+++ b/fs/notify/dnotify/dnotify.c
@@ -308,6 +308,10 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned int arg)
 		goto out_err;
 	}
 
+	error = file_f_owner_allocate(filp);
+	if (error)
+		goto out_err;
+
 	/* new fsnotify mark, we expect most fcntl calls to add a new mark */
 	new_dn_mark = kmem_cache_alloc(dnotify_mark_cache, GFP_KERNEL);
 	if (!new_dn_mark) {
@@ -315,10 +319,6 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned int arg)
 		goto out_err;
 	}
 
-	error = file_f_owner_allocate(filp);
-	if (error)
-		goto out_err;
-
 	/* set up the new_fsn_mark and new_dn_mark */
 	new_fsn_mark = &new_dn_mark->fsn_mark;
 	fsnotify_init_mark(new_fsn_mark, dnotify_group);
-- 
2.39.5