[PATCH 6.6 367/567] ksmbd: call ksmbd_vfs_kern_path_end_removing() on some error paths

Greg Kroah-Hartman
2026-03-23T15:10:31Z

6.6-stable review patch. If anyone has any objections, please let me know.

------------------

From: Fedor Pchelkin <pchelkin@ispras.ru>

[ Upstream commit a09dc10d1353f0e92c21eae2a79af1c2b1ddcde8 ]

There are two places where ksmbd_vfs_kern_path_end_removing() needs to be
called in order to balance what the corresponding successful call to
ksmbd_vfs_kern_path_start_removing() has done, i.e. drop inode locks and
put the taken references. Otherwise there might be potential deadlocks
and unbalanced locks which are caught like:

BUG: workqueue leaked lock or atomic: kworker/5:21/0x00000000/7596
last function: handle_ksmbd_work
2 locks held by kworker/5:21/7596:
#0: ffff8881051ae448 (sb_writers#3){.+.+}-{0:0}, at: ksmbd_vfs_kern_path_locked+0x142/0x660
#1: ffff888130e966c0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: ksmbd_vfs_kern_path_locked+0x17d/0x660
CPU: 5 PID: 7596 Comm: kworker/5:21 Not tainted 6.1.162-00456-gc29b353f383b #138
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
Workqueue: ksmbd-io handle_ksmbd_work
Call Trace:
<TASK>
dump_stack_lvl+0x44/0x5b
process_one_work.cold+0x57/0x5c
worker_thread+0x82/0x600
kthread+0x153/0x190
ret_from_fork+0x22/0x30
</TASK>

Found by Linux Verification Center (linuxtesting.org).

Fixes: d5fc1400a34b ("smb/server: avoid deadlock when linking with ReplaceIfExists")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
[ ksmbd_vfs_kern_path_end_removing() call -> ksmbd_vfs_kern_path_unlock() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/smb/server/smb2pdu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -6067,14 +6067,14 @@ static int smb2_create_link(struct ksmbd
rc = -EINVAL;
ksmbd_debug(SMB, "cannot delete %s\n",
link_name);
- goto out;
}
} else {
rc = -EEXIST;
ksmbd_debug(SMB, "link already exists\n");
- goto out;
}
ksmbd_vfs_kern_path_unlock(&parent_path, &path);
+ if (rc)
+ goto out;
}
rc = ksmbd_vfs_link(work, target_name, link_name);
if (rc)