Re: Hang: 188.8.131.52 sky2/DMAR (was [PATCH] sky2: Fix WARNING: atlib/dma-debug.c:902 check_sync)
From: Michael Breuer
Date: Thu Jan 28 2010 - 10:32:18 EST
On 01/27/2010 01:45 PM, Michael Breuer wrote:
On 1/27/2010 1:08 PM, Michael Breuer wrote:
Just FYI - still crashes with default copybreak. Didn't get the netdev
watchdog this time - just DMAR and then HW watchdog reboot (see below).
Never mind - that was from one of the earlier patches I had been
trying out. will try the above patch after reestablishing that the
system still crashes without copybreak=1.
I've got (both in 184.108.40.206 and 2.6.33-rc5: pci_unmap_len(re,
data_size) vs., "length." I assume that I can just replace the
pci_unmap_len with dma_size... but perhaps the intermediate change
may have affected this as well?
So what's known to be required to cause this crash:
1) sky2 @ 1Gb
2) High sustained RX load (> 40MBps)
3) Uptime (I can't cause this to happen just after boot).
4) DMAR enabled (doesn't crash w/o DMAR).
5) copybreak != 1
What might be required but is unproven:
1) cifs traffic (I've only seen this when the high traffic was due to a
Win7 box doing backup). I've tried but have been unable to recreate by
just copying large files. Backups done from a Mac OS laptop don't
trigger the issue even though that machine is also connecting with CIFS
(TimeMachine works better that way).
2) DHCP traffic. There has always been some sort of DHCP exchange in the
log before the first indication of a problem (DMAR).
3) Total throughput since boot. DK about this - however the uptime
component before the latest crash was the shortest yet. In preparation I
moved a bunch of large files around on the Windows box to ensure a
larger than normal backup run. I also ran manually before going to bed
(then moved the files around again). Didn't crash when I was watching -
but did overnight. Total uptime before this crash was only about 6
hours. Previously (with less backup data) the system didn't crash until
Copybreak: I did play for an hour or so yesterday with copybreak=1000.
Ran traffic, etc. No crash, but throughput was lower and the system was
clearly working way harder than normal. Given the whine of the fans I'm
not keen on leaving the system in that state for any extended period of
MTU: Increasing the MTU to 9000 yesterday after the system had been up
for some time (copybreak=1) crashed the system immediately. Subsequently
I have been able to change the mtu without crashes (although the driver
does end up in some sort of state that requires a restart after lowering
the mtu). I suspect that over time something is being corrupted
resulting in the crash when changing mtu. Whatever it becoming corrupted
is probably related to the other crash as well. That suggests to me that
copybreak=1 is preventing or delaying the manifestation of the
underlying issue but is unrelated to the source of corruption.
[no messages in the prior three minutes - there was a dhcp exchange
(request/ack) at 06:02:27]
Jan 28 06:05:58 mail kernel: DRHD: handling fault status reg 2
Jan 28 06:05:58 mail kernel: DMAR:[DMA Read] Request device [06:00.0]
fault addr ffdd06bfe000
Jan 28 06:05:58 mail kernel: DMAR:[fault reason 06] PTE Read access is
Jan 28 06:05:58 mail kernel: sky2 0000:06:00.0: error interrupt
Jan 28 06:05:58 mail kernel: sky2 0000:06:00.0: PCI hardware error (0x2010)
[No further messages until restart at 06:09:46.]
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