WARNING: at fs/xfs/linux-2.6/xfs_aops.c:1289 xfs_vm_releasepage+0x32/0x41()

WARNING: at fs/xfs/linux-2.6/xfs_aops.c:1289 xfs_vm_releasepage+0x32/0x41()

[Jeffrey Hundstad]

Hello,

I'm not sure if this is interesting at all.  Let me know if it is, I can 
do bisects if needed, let me know which config additions you need for 
debugging.

The warning happens during a Debian/Sid "aptitude update."  It doesn't 
happen on linux-2.6.34.6 but it does on linux-2.6.36 and linux-2.6.37-rc2.


Here's the WARNING.  Config, and full dmesg at:
http://krypton.mnsu.edu/~j3gum/linux-error-20101116/

------------[ cut here ]------------
WARNING: at fs/xfs/linux-2.6/xfs_aops.c:1289 xfs_vm_releasepage+0x32/0x41()
Hardware name: OptiPlex GX110
Modules linked in: nf_conntrack_ftp ipt_MASQUERADE iptable_nat ip_tables 
nf_nat x_tables nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 microcode 
8250_pnp rtc_cmos e100 8250 rtc_core floppy serial_core processor 
rtc_lib mii button
Pid: 234, comm: kswapd0 Not tainted 2.6.37-rc2 #1
Call Trace:
  [<c1019687>] ? warn_slowpath_common+0x7c/0x8f
  [<c10dbdcc>] ? xfs_vm_releasepage+0x32/0x41
  [<c10dbdcc>] ? xfs_vm_releasepage+0x32/0x41
  [<c10196b5>] ? warn_slowpath_null+0x1b/0x1e
  [<c10dbdcc>] ? xfs_vm_releasepage+0x32/0x41
  [<c1046672>] ? try_to_release_page+0x2c/0x3c
  [<c104fc12>] ? shrink_page_list+0x47d/0x5e3
  [<c104ea7a>] ? isolate_lru_pages+0x64/0x1cf
  [<c104fee4>] ? shrink_inactive_list+0x16c/0x1f3
  [<c1050272>] ? shrink_zone+0x307/0x3af
  [<c10506c6>] ? kswapd+0x3ac/0x574
  [<c102b335>] ? autoremove_wake_function+0x0/0x31
  [<c105031a>] ? kswapd+0x0/0x574
  [<c102b15f>] ? kthread+0x62/0x67
  [<c102b0fd>] ? kthread+0x0/0x67
  [<c1002b16>] ? kernel_thread_helper+0x6/0x10
---[ end trace 8b9e3e1349c73905 ]---

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

Re: WARNING: at fs/xfs/linux-2.6/xfs_aops.c:1289 xfs_vm_releasepage+0x32/0x41()

[Christoph Hellwig]

On Tue, Nov 16, 2010 at 07:52:16PM -0600, Jeffrey Hundstad wrote:
> Hello,
> 
> I'm not sure if this is interesting at all.  Let me know if it is, I
> can do bisects if needed, let me know which config additions you
> need for debugging.

It's very interesting.  I put these WARN_ONs in because we believed we
could never get a releasepage call with delayed or unwritten extents
still on.  Previous it could happen during truncate, but with the new
truncate sequence that should be gone.  Your trace on the other hand
comes from kswapd.

>  [<c1019687>] ? warn_slowpath_common+0x7c/0x8f
>  [<c10dbdcc>] ? xfs_vm_releasepage+0x32/0x41
>  [<c10dbdcc>] ? xfs_vm_releasepage+0x32/0x41
>  [<c10196b5>] ? warn_slowpath_null+0x1b/0x1e
>  [<c10dbdcc>] ? xfs_vm_releasepage+0x32/0x41
>  [<c1046672>] ? try_to_release_page+0x2c/0x3c
>  [<c104fc12>] ? shrink_page_list+0x47d/0x5e3
>  [<c104ea7a>] ? isolate_lru_pages+0x64/0x1cf
>  [<c104fee4>] ? shrink_inactive_list+0x16c/0x1f3
>  [<c1050272>] ? shrink_zone+0x307/0x3af
>  [<c10506c6>] ? kswapd+0x3ac/0x574
>  [<c102b335>] ? autoremove_wake_function+0x0/0x31
>  [<c105031a>] ? kswapd+0x0/0x574
>  [<c102b15f>] ? kthread+0x62/0x67
>  [<c102b0fd>] ? kthread+0x0/0x67
>  [<c1002b16>] ? kernel_thread_helper+0x6/0x10

This looks like some sort of race between writepage and redirtying.

Let me think about it a bit more, but I think it's harmless.  What
worries me more is that aptitude is apparently able to trigger
kswapd writeback easily.

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs