fs/ntfs3: Fix possible deadlock in mi_read

aalexandrovich · aalexandrovich · commit 03b097099eef · 2024-10-01T12:19:06.000+03:00
Mutex lock with another subclass used in ni_lock_dir().

Reported-by: syzbot+bc7ca0ae4591cb2550f9@syzkaller.appspotmail.com
Signed-off-by: Konstantin Komarov &lt;almaz.alexandrovich@paragon-software.com&gt;
diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
@@ -81,7 +81,7 @@ static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
 		if (err < 0)
 			inode = ERR_PTR(err);
 		else {
-			ni_lock(ni);
+			ni_lock_dir(ni);
 			inode = dir_search_u(dir, uni, NULL);
 			ni_unlock(ni);
 		}

Original file line number	Diff line number	Diff line change
`@@ -81,7 +81,7 @@ static struct dentry ntfs_lookup(struct inode dir, struct dentry *dentry,`
`81`	`81`	`if (err < 0)`
`82`	`82`	`inode = ERR_PTR(err);`
`83`	`83`	`else {`
`84`		`- ni_lock(ni);`
	`84`	`+ ni_lock_dir(ni);`
`85`	`85`	`inode = dir_search_u(dir, uni, NULL);`
`86`	`86`	`ni_unlock(ni);`
`87`	`87`	`}`