diff options
| author | NeilBrown <neil@brown.name> | 2025-08-04 22:11:28 +1000 |
|---|---|---|
| committer | Amir Goldstein <amir73il@gmail.com> | 2025-08-18 13:16:38 +0200 |
| commit | 5f1c8965e748c150d580a2ea8fbee1bd80d07a24 (patch) | |
| tree | 4f385461d955b312190cc524b92123f2eb2de850 | |
| parent | 8f5ae30d69d7543eee0d70083daf4de8fe15d585 (diff) | |
ovl: use I_MUTEX_PARENT when locking parent in ovl_create_temp()
ovl_create_temp() treats "workdir" as a parent in which it creates an
object so it should use I_MUTEX_PARENT.
Prior to the commit identified below the lock was taken by the caller
which sometimes used I_MUTEX_PARENT and sometimes used I_MUTEX_NORMAL.
The use of I_MUTEX_NORMAL was incorrect but unfortunately copied into
ovl_create_temp().
Note to backporters: This patch only applies after the last Fixes given
below (post v6.16). To fix the bug in v6.7 and later the
inode_lock() call in ovl_copy_up_workdir() needs to nest using
I_MUTEX_PARENT.
Link: https://lore.kernel.org/all/67a72070.050a0220.3d72c.0022.GAE@google.com/
Cc: stable@vger.kernel.org
Reported-by: syzbot+7836a68852a10ec3d790@syzkaller.appspotmail.com
Tested-by: syzbot+7836a68852a10ec3d790@syzkaller.appspotmail.com
Fixes: c63e56a4a652 ("ovl: do not open/llseek lower file with upper sb_writers held")
Fixes: d2c995581c7c ("ovl: Call ovl_create_temp() without lock held.")
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
| -rw-r--r-- | fs/overlayfs/dir.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 70b8687dc45e..dbd63a74df4b 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -225,7 +225,7 @@ struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir, struct ovl_cattr *attr) { struct dentry *ret; - inode_lock(workdir->d_inode); + inode_lock_nested(workdir->d_inode, I_MUTEX_PARENT); ret = ovl_create_real(ofs, workdir, ovl_lookup_temp(ofs, workdir), attr); inode_unlock(workdir->d_inode); |