[PATCH 4.19 054/105] btrfs: free btrfs_path before copying fspath to userspace

Greg Kroah-Hartman
2022-12-05T19:20:13Z

From: Anand Jain <anand.jain@oracle.com>

commit 8cf96b409d9b3946ece58ced13f92d0f775b0442 upstream.

btrfs_ioctl_ino_to_path() frees the search path after the userspace copy
from the temp buffer @ipath->fspath. Which potentially can lead to a lock
splat warning.

Fix this by freeing the path before we copy it to userspace.

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/ioctl.c | 2 ++
1 file changed, 2 insertions(+)

--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4887,6 +4887,8 @@ static long btrfs_ioctl_ino_to_path(stru
ipath->fspath->val[i] = rel_ptr;
}

+ btrfs_free_path(path);
+ path = NULL;
ret = copy_to_user((void __user *)(unsigned long)ipa->fspath,
ipath->fspath, size);
if (ret) {