diff options
| author | NeilBrown <neil@brown.name> | 2025-08-04 22:11:28 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-28 16:34:41 +0200 |
| commit | 12403bffed983339ec3975b5ec9037520c12eee8 (patch) | |
| tree | 3cd4a9ef243b0f9ac05348d66cd53bf6aa0fbb00 | |
| parent | 3079517a5ba80901fe828a06998da64b9b8749be (diff) | |
ovl: use I_MUTEX_PARENT when locking parent in ovl_create_temp()
commit 5f1c8965e748c150d580a2ea8fbee1bd80d07a24 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/overlayfs/copy_up.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index d7310fcf3888..c2263148ff20 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -779,7 +779,7 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c) return err; ovl_start_write(c->dentry); - inode_lock(wdir); + inode_lock_nested(wdir, I_MUTEX_PARENT); temp = ovl_create_temp(ofs, c->workdir, &cattr); inode_unlock(wdir); ovl_end_write(c->dentry); |