Darrick J. Wong 044d098441 xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT
commit 1fb254aa983bf190cfd685d40c64a480a9bafaee upstream.

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>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-29 08:26:45 +02:00
2019-08-16 10:13:55 +02:00
2019-08-25 10:50:29 +02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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