[Karmic] Fix kernel crash with jfs

[Andy Whitcroft]

On Thu, Jul 23, 2009 at 04:29:52PM +0200, Stefan Bader wrote:
> 
> Just found the solution to that nasty bug#396780 which is caused by jfs
> releasing some acl before returning. The patch has been verified to be working
> and I will submit it upstream ASAP.
> 

> From a345a80ca7a926c9c6e322a1e8add4817c834d0f Mon Sep 17 00:00:00 2001
> From: Stefan Bader <stefan.bader at canonical.com>
> Date: Thu, 23 Jul 2009 11:26:05 +0200
> Subject: [PATCH] jfs: Fix early release of acl in jfs_get_acl
> 
> BugLink: http://bugs.launchpad.net/ubuntu/+bug/396780
> 
> Commit 073aaa1b142461d91f83da66db1184d7c1b1edea "helpers for acl
> caching + switch to those" introduced new helper function for
> acl handling but seems to introduce a regression for jfs as the
> acl is released before returning it to the caller, instead of
> leaving this for the caller to do.
> This causes the acl object to be used after freeing it, leading
> to kernel panics at completely different places.
> 
> Thanks to Christophe Dumez for reporting and bisecting into this.
> 
> Reported-by: Christophe Dumez <dchris at gmail.com>
> Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
> ---
>  fs/jfs/acl.c |    4 +---
>  1 files changed, 1 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/jfs/acl.c b/fs/jfs/acl.c
> index f272bf0..3c88d1b 100644
> --- a/fs/jfs/acl.c
> +++ b/fs/jfs/acl.c
> @@ -67,10 +67,8 @@ static struct posix_acl *jfs_get_acl(struct inode *inode, int type)
>  		acl = posix_acl_from_xattr(value, size);
>  	}
>  	kfree(value);
> -	if (!IS_ERR(acl)) {
> +	if (!IS_ERR(acl))
>  		set_cached_acl(inode, type, acl);
> -		posix_acl_release(acl);
> -	}
>  	return acl;
>  }

I reviewed all of the callers of jfs_get_acl and they are assuming that
they have a reference on the acl and should be releasing it.  So this
change looks right to me.

ACK

For upstream:

Acked-by: Andy Whitcroft <apw at canonical.com>

-apw