From: Lizhi Xu lizhi.xu@windriver.com
[ Upstream commit 17a4fde81d3a7478d97d15304a6d61094a10c2e3 ]
syzbot reported a lock held when returning to userspace[1]. This is because if argc is less than 0 and the function returns directly, the held inode lock is not released.
Fix this by store the error in ret and jump to done to clean up instead of returning directly.
[dh: Modified Lizhi Xu's original patch to make it honour the error code from afs_split_string()]
[1] WARNING: lock held when returning to user space! 6.13.0-rc3-syzkaller-00209-g499551201b5f #0 Not tainted ------------------------------------------------ syz-executor133/5823 is leaving the kernel with locks still held! 1 lock held by syz-executor133/5823: #0: ffff888071cffc00 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline] #0: ffff888071cffc00 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: afs_proc_addr_prefs_write+0x2bb/0x14e0 fs/afs/addr_prefs.c:388
Reported-by: syzbot+76f33569875eb708e575@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=76f33569875eb708e575 Signed-off-by: Lizhi Xu lizhi.xu@windriver.com Signed-off-by: David Howells dhowells@redhat.com Link: https://lore.kernel.org/r/20241226012616.2348907-1-lizhi.xu@windriver.com/ Link: https://lore.kernel.org/r/529850.1736261552@warthog.procyon.org.uk Tested-by: syzbot+76f33569875eb708e575@syzkaller.appspotmail.com cc: Marc Dionne marc.dionne@auristor.com cc: linux-afs@lists.infradead.org Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/afs/addr_prefs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/afs/addr_prefs.c b/fs/afs/addr_prefs.c index a189ff8a5034..c0384201b8fe 100644 --- a/fs/afs/addr_prefs.c +++ b/fs/afs/addr_prefs.c @@ -413,8 +413,10 @@ int afs_proc_addr_prefs_write(struct file *file, char *buf, size_t size)
do { argc = afs_split_string(&buf, argv, ARRAY_SIZE(argv)); - if (argc < 0) - return argc; + if (argc < 0) { + ret = argc; + goto done; + } if (argc < 2) goto inval;