[PATCH] fs: Fix bug in lock_rename_child that can cause deadlock

From: Li Dong
Date: Mon Jun 19 2023 - 09:38:02 EST


Function xx causes a deadlock,because s_vfs_rename_mutex was not released when return

Signed-off-by: Li Dong <lidong@xxxxxxxx>
---
fs/namei.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index 91171da719c5..63b3fd05fef2 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3076,8 +3076,10 @@ struct dentry *lock_rename_child(struct dentry *c1, struct dentry *p2)
/*
* nobody can move out of any directories on this fs.
*/
- if (likely(c1->d_parent != p2))
+ if (likely(c1->d_parent != p2)) {
+ mutex_unlock(&c1->d_sb->s_vfs_rename_mutex);
return lock_two_directories(c1->d_parent, p2);
+ }

/*
* c1 got moved into p2 while we were taking locks;
--
2.31.1.windows.1