Re: 4.4.16: ovl: BUG() in notify_change()

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Aug 03, 2016 at 05:02:41AM -0500, Eric Schultz wrote:
> 
> > On Aug 3, 2016, at 12:45 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> > 
> > On Sat, Jul 30, 2016 at 10:28:16AM -0500, Eric Schultz wrote:
> >> Hey Greg,
> >> 
> >> Apologies in advance if this isn’t the correct method or channel to report bugs
> >> with kernel 4.4.16.
> >> 
> >> Commit c12dada5f28a4894b81df2666c060f5cecc02cf9 was included in kernel 4.4.16
> >> but relies on its parent upstream commit 
> >> b99c2d913810e56682a538c9f2394d76fca808f8, currently missing from
> >> 4.4.16, otherwise BUG() is thrown for certain operations in overlayfs (I’m able
> >> to reproduce the issue).  I can confirm porting upstream commit 
> >> b99c2d913810e56682a538c9f2394d76fca808f8 in to kernel 4.4.16 solves the issues.
> >> Please let me know if I could help out in any other way.
> > 
> > This patch does not apply to the 4.4.y stable tree, can you provide a
> > backport?
> > 
> > thanks,
> > 
> > greg k-h
> 
> No problem, attached is a appliable patch for 4.4.y and was taken 
> from https://bugzilla.kernel.org/show_bug.cgi?id=150711
> 
> 
> --- a/fs/overlayfs/inode.c	2016-07-31 15:41:55.613057608 +0200
> +++ a/fs/overlayfs/inode.c	2016-07-31 15:46:24.498060788 +0200
> @@ -63,6 +63,9 @@ 
>  	if (!err) {
>  		upperdentry = ovl_dentry_upper(dentry);
>  
> +		if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
> +			attr->ia_valid &= ~ATTR_MODE;
> +
>  		mutex_lock(&upperdentry->d_inode->i_mutex);
>  		err = notify_change(upperdentry, attr, NULL);
>  		if (!err)

Thanks, that worked!

greg k-h