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From: Salvatore Bonaccorso <carnil@debian.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: xfs <linux-xfs@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Dave Chinner <david@fromorbit.com>,
	Security Officers <security@kernel.org>,
	Debian Security Team <team@security.debian.org>,
	benjamin.moody@gmail.com, Ben Hutchings <benh@debian.org>,
	Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH] xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT
Date: Fri, 23 Aug 2019 21:24:33 +0200
Message-ID: <20190823192433.GA8736@eldamar.local> (raw)
In-Reply-To: <20190823035528.GH1037422@magnolia>

Hi Darrick,

On Thu, Aug 22, 2019 at 08:55:28PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Benjamin Moody reported to Debian that XFS partially wedges when a chgrp
> fails on account of being out of disk quota.  I ran his reproducer
> script:
> 
> # adduser dummy
> # adduser dummy plugdev
> 
> # dd if=/dev/zero bs=1M count=100 of=test.img
> # mkfs.xfs test.img
> # mount -t xfs -o gquota test.img /mnt
> # mkdir -p /mnt/dummy
> # chown -c dummy /mnt/dummy
> # xfs_quota -xc 'limit -g bsoft=100k bhard=100k plugdev' /mnt
> 
> (and then as user dummy)
> 
> $ dd if=/dev/urandom bs=1M count=50 of=/mnt/dummy/foo
> $ chgrp plugdev /mnt/dummy/foo
> 
> and saw:
> 
> ================================================
> WARNING: lock held when returning to user space!
> 5.3.0-rc5 #rc5 Tainted: G        W
> ------------------------------------------------
> chgrp/47006 is leaving the kernel with locks still held!
> 1 lock held by chgrp/47006:
>  #0: 000000006664ea2d (&xfs_nondir_ilock_class){++++}, at: xfs_ilock+0xd2/0x290 [xfs]
> 
> ...which is clearly caused by xfs_setattr_nonsize failing to unlock the
> ILOCK after the xfs_qm_vop_chown_reserve call fails.  Add the missing
> unlock.
> 
> Reported-by: benjamin.moody@gmail.com
> Fixes: 253f4911f297 ("xfs: better xfs_trans_alloc interface")
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/xfs/xfs_iops.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index dd4076ae228a..ea614b4ae052 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -804,6 +804,7 @@ xfs_setattr_nonsize(
>  
>  out_cancel:
>  	xfs_trans_cancel(tp);
> +	xfs_iunlock(ip, XFS_ILOCK_EXCL);
>  out_dqrele:
>  	xfs_qm_dqrele(udqp);
>  	xfs_qm_dqrele(gdqp);

Confirmed the fix work.

Feel free to add a Tested-by if wanted.

Can this be backported to the relevant stable versions as well?

Regards,
Salvatore

  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-23  3:55 Darrick J. Wong
2019-08-23  3:57 ` [PATCH] generic: test for failure to unlock inode after chgrp fails with EDQUOT Darrick J. Wong
2019-08-24 23:05   ` Christoph Hellwig
2019-08-23  4:55 ` [PATCH] xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT Dave Chinner
2019-08-23 16:28 ` Linus Torvalds
2019-08-23 17:15   ` Benjamin Moody
2019-08-23 19:26   ` Salvatore Bonaccorso
2019-08-24 18:22     ` Salvatore Bonaccorso
2019-08-23 19:24 ` Salvatore Bonaccorso [this message]
2019-08-24 18:44   ` Linus Torvalds
2019-08-25  3:13     ` Greg KH
2019-08-25 15:45       ` Salvatore Bonaccorso

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