This is a note to let you know that I've just added the patch titled
vfs: fix deadlock in file_remove_privs() on overlayfs
to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vfs-fix-deadlock-in-file_remove_privs-on-overlayfs.patch
and it can be found in the queue-4.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c1892c37769cf89c7e7ba57528ae2ccb5d153c9b Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Date: Wed, 3 Aug 2016 13:44:27 +0200
Subject: vfs: fix deadlock in file_remove_privs() on overlayfs
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
commit c1892c37769cf89c7e7ba57528ae2ccb5d153c9b upstream.
file_remove_privs() is called with inode lock on file_inode(), which
proceeds to calling notify_change() on file->f_path.dentry. Which triggers
the WARN_ON_ONCE(!inode_is_locked(inode)) in addition to deadlocking later
when ovl_setattr tries to lock the underlying inode again.
Fix this mess by not mixing the layers, but doing everything on underlying
dentry/inode.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Fixes: 07a2daab49c5 ("ovl: Copy up underlying inode's ->i_mode to overlay inode")
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/inode.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1739,8 +1739,8 @@ static int __remove_privs(struct dentry
*/
int file_remove_privs(struct file *file)
{
- struct dentry *dentry = file->f_path.dentry;
- struct inode *inode = d_inode(dentry);
+ struct dentry *dentry = file_dentry(file);
+ struct inode *inode = file_inode(file);
int kill;
int error = 0;
@@ -1748,7 +1748,7 @@ int file_remove_privs(struct file *file)
if (IS_NOSEC(inode))
return 0;
- kill = file_needs_remove_privs(file);
+ kill = dentry_needs_remove_privs(dentry);
if (kill < 0)
return kill;
if (kill)
Patches currently in stable-queue which might be from mszeredi@xxxxxxxxxx are
queue-4.6/vfs-fix-deadlock-in-file_remove_privs-on-overlayfs.patch
queue-4.6/9p-use-file_dentry.patch
queue-4.6/locks-use-file_inode.patch
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