| From hch@lst.de Mon Sep 18 10:09:04 2017 |
| From: Christoph Hellwig <hch@lst.de> |
| Date: Sun, 17 Sep 2017 14:06:39 -0700 |
| Subject: xfs: fix quotacheck dquot id overflow infinite loop |
| To: stable@vger.kernel.org |
| Cc: linux-xfs@vger.kernel.org, Brian Foster <bfoster@redhat.com>, "Darrick J . Wong" <darrick.wong@oracle.com> |
| Message-ID: <20170917210712.10804-15-hch@lst.de> |
| |
| |
| From: Brian Foster <bfoster@redhat.com> |
| |
| commit cfaf2d034360166e569a4929dd83ae9698bed856 upstream. |
| |
| If a dquot has an id of U32_MAX, the next lookup index increment |
| overflows the uint32_t back to 0. This starts the lookup sequence |
| over from the beginning, repeats indefinitely and results in a |
| livelock. |
| |
| Update xfs_qm_dquot_walk() to explicitly check for the lookup |
| overflow and exit the loop. |
| |
| Signed-off-by: Brian Foster <bfoster@redhat.com> |
| Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> |
| Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| fs/xfs/xfs_qm.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/fs/xfs/xfs_qm.c |
| +++ b/fs/xfs/xfs_qm.c |
| @@ -111,6 +111,9 @@ restart: |
| skipped = 0; |
| break; |
| } |
| + /* we're done if id overflows back to zero */ |
| + if (!next_index) |
| + break; |
| } |
| |
| if (skipped) { |
