lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 18 Sep 2017 11:11:54 +0200 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, linux-xfs@...r.kernel.org, "Darrick J . Wong" <darrick.wong@...cle.com>, Christoph Hellwig <hch@....de>, Nikolay Borisov <n.borisov.lkml@...il.com> Subject: [PATCH 4.9 45/78] xfs: fix multi-AG deadlock in xfs_bunmapi 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ commit 5b094d6dac0451ad89b1dc088395c7b399b7e9e8 upstream. Just like in the allocator we must avoid touching multiple AGs out of order when freeing blocks, as freeing still locks the AGF and can cause the same AB-BA deadlocks as in the allocation path. Signed-off-by: Christoph Hellwig <hch@....de> Reported-by: Nikolay Borisov <n.borisov.lkml@...il.com> Reviewed-by: Darrick J. Wong <darrick.wong@...cle.com> Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- fs/xfs/libxfs/xfs_bmap.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -5556,6 +5556,7 @@ __xfs_bunmapi( xfs_fsblock_t sum; xfs_filblks_t len = *rlen; /* length to unmap in file */ xfs_fileoff_t max_len; + xfs_agnumber_t prev_agno = NULLAGNUMBER, agno; trace_xfs_bunmap(ip, bno, len, flags, _RET_IP_); @@ -5658,6 +5659,17 @@ __xfs_bunmapi( ASSERT(ep != NULL); del = got; wasdel = isnullstartblock(del.br_startblock); + + /* + * Make sure we don't touch multiple AGF headers out of order + * in a single transaction, as that could cause AB-BA deadlocks. + */ + if (!wasdel) { + agno = XFS_FSB_TO_AGNO(mp, del.br_startblock); + if (prev_agno != NULLAGNUMBER && prev_agno > agno) + break; + prev_agno = agno; + } if (got.br_startoff < start) { del.br_startoff = start; del.br_blockcount -= start - got.br_startoff;
Powered by blists - more mailing lists