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From: Alex Elder <aelder@sgi.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 2/8] xfs: fix efi item leak on forced shutdown
Date: Fri, 28 Jan 2011 08:54:10 -0600	[thread overview]
Message-ID: <1296226450.2342.5.camel@doink> (raw)
In-Reply-To: <1296100401-17135-3-git-send-email-david@fromorbit.com>

On Thu, 2011-01-27 at 14:53 +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> After test 139, kmemleak shows:
> 
> unreferenced object 0xffff880078b405d8 (size 400):
>   comm "xfs_io", pid 4904, jiffies 4294909383 (age 1186.728s)
>   hex dump (first 32 bytes):
>     60 c1 17 79 00 88 ff ff 60 c1 17 79 00 88 ff ff  `..y....`..y....
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff81afb04d>] kmemleak_alloc+0x2d/0x60
>     [<ffffffff8115c6cf>] kmem_cache_alloc+0x13f/0x2b0
>     [<ffffffff814aaa97>] kmem_zone_alloc+0x77/0xf0
>     [<ffffffff814aab2e>] kmem_zone_zalloc+0x1e/0x50
>     [<ffffffff8147cd6b>] xfs_efi_init+0x4b/0xb0
>     [<ffffffff814a4ee8>] xfs_trans_get_efi+0x58/0x90
>     [<ffffffff81455fab>] xfs_bmap_finish+0x8b/0x1d0
>     [<ffffffff814851b4>] xfs_itruncate_finish+0x2c4/0x5d0
>     [<ffffffff814a970f>] xfs_setattr+0x8df/0xa70
>     [<ffffffff814b5c7b>] xfs_vn_setattr+0x1b/0x20
>     [<ffffffff8117dc00>] notify_change+0x170/0x2e0
>     [<ffffffff81163bf6>] do_truncate+0x66/0xa0
>     [<ffffffff81163d0b>] sys_ftruncate+0xdb/0xe0
>     [<ffffffff8103a002>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> 
> The cause of the leak is that the "remove" parameter of IOP_UNPIN()
> is never set when a CIL push is aborted. This means that the EFI
> item is never freed if it was in the push being cancelled. The
> problem is specific to delayed logging, but has uncovered a couple
> of problems with the handling of IOP_UNPIN(remove).
> 
> Firstly, we cannot safely call xfs_trans_del_item() from IOP_UNPIN()
> in the CIL commit failure path or the iclog write failure path
> because for delayed loging we have no transaction context. Hence we
> must only call xfs_trans_del_item() if the log item being unpinned
> has an active log item descriptor.
> 
> Secondly, xfs_trans_uncommit() does not handle log item descriptor
> freeing during the traversal of log items on a transaction. It can
> reference a freed log item descriptor when unpinning an EFI item.
> Hence it needs to use a safe list traversal method to allow items to
> be removed from the transaction during IOP_UNPIN().
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

OK, this looks good.

Reviewed-by: Alex Elder <aelder@sgi.com>


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  reply	other threads:[~2011-01-28 14:51 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-27  3:53 [PATCH 0/8] xfs: candidate 2.6.38-rc fixes V3 Dave Chinner
2011-01-27  3:53 ` [PATCH 1/8] xfs: fix log ticket leak on forced shutdown Dave Chinner
2011-01-27  3:53 ` [PATCH 2/8] xfs: fix efi item " Dave Chinner
2011-01-28 14:54   ` Alex Elder [this message]
2011-01-27  3:53 ` [PATCH 3/8] xfs: speculative delayed allocation uses rounddown_power_of_2 badly Dave Chinner
2011-01-27  3:53 ` [PATCH 4/8] xfs: limit extent length for allocation to AG size Dave Chinner
2011-01-27  3:53 ` [PATCH 5/8] xfs: prevent extsize alignment from exceeding maximum extent size Dave Chinner
2011-01-27  3:53 ` [PATCH 6/8] xfs: limit extsize to size of AGs and/or MAXEXTLEN Dave Chinner
2011-01-27  3:53 ` [PATCH 7/8] xfs: handle CIl transaction commit failures correctly Dave Chinner
2011-01-27  3:53 ` [PATCH 8/8] xfs: fix dquot shaker deadlock Dave Chinner
2011-01-27 15:29   ` Alex Elder
2011-01-27 15:31 ` [PATCH 0/8] xfs: candidate 2.6.38-rc fixes V3 Alex Elder
2011-01-28  0:42   ` Dave Chinner
  -- strict thread matches above, loose matches on Subject: below --
2011-01-25  8:50 [PATCH 0/8] xfs: 2.6.38-rc candidate fixes V2 Dave Chinner
2011-01-25  8:50 ` [PATCH 2/8] xfs: fix efi item leak on forced shutdown Dave Chinner
2011-01-25 23:53   ` Christoph Hellwig
2011-01-27  0:35     ` Dave Chinner
2011-01-26 21:22   ` Alex Elder

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