[Fedora-xen] dom0 F7 crashes tcp_tso_segment oops - new kernel lag time

[Richard W.M. Jones]

Dale Bewley wrote:
> Running 2.6.20-2936.fc7xen x86_64 quad CPU, 16G.
> 
> We have a dom0 with bridges riding on top of a VLAN interface.
> 
> # brctl show
> bridge name     bridge id               STP enabled     interfaces
> br101           8000.00093d139ae9       no              eth0
> br6             8000.00093d139ae9       no              vif2.0
>                                                         vif1.0
>                                                         eth0.6
> ...
> 
> Inside a F7 domU on br6 we are running tc (via shorewall) to limit the bandwidth of a mirror server. On Monday I throttled the bandwidth down far below the demand. Since then we are starting to see dom0 crash and reboot with nothing in the log. 
> 
> Crashes happened on Tues around 9am and Thursday (today) around 4am and 9am. I caught the console during the most recent crash:
> 
> Unable to handle kernel NULL pointer dereference at 0000000000000030 RIP:
>  [<ffffffff803fc79c>] tcp_tso_segment+0x1d8/0x285
> PGD 3db8f1067 PUD 3db8f2067 PMD 0
> Oops: 0000 [1] SMP
> last sysfs file: /devices/xen-backend/vbd-2-51712/statistics/wr_sect
> CPU 1
> Modules linked in: loop netbk xenblktap blkbk autofs4 8021q bridge nf_conntrack_netbios_ns ipt_LdPid: 0, comm: swapper Not tainted 2.6.20-2936.fc7xen #1
> RIP: e030:[<ffffffff803fc79c>]  [<ffffffff803fc79c>] tcp_tso_segment+0x1d8/0x285
> RSP: e02b:ffff880002f77950  EFLAGS: 00010216
> RAX: 0000000000007a21 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000010130000 RSI: 0000000000000000 RDI: 0000000087e8b626
> RBP: 000000000000fa87 R08: 0000000187e8b625 R09: 0000000000000000
> R10: 000000009b9a7b25 R11: 0000000000000003 R12: ffff88034ecab034
> R13: 0000000017acfe00 R14: 0000000000000020 R15: 00000000ffff0000
> FS:  00002aaaab0ff230(0000) GS:ffffffff80580080(0000) knlGS:0000000000000000
> 
> We are up to date with patches. After the first 2 crashes and before the 3rd I upgraded from xen-3.1.0-6.fc7 to xen-3.1.0-8.fc7 and rebooted dom0 for good measure.
> 
> I did some googling and found this:
> http://lists.openwall.net/netdev/2007/02/09/16
> which seems pretty similar. 
> 
> Assuming this is the problem and there is a fix I'm left to ask what is the ETA for a new xen kernel and what is the typical lag time? 
> 
> Current state is 2.6.23.1-21.fc7 vs. 2.6.20-2936.fc7xen

I wonder if it is worth your while trying the Xen stack & kernel from 
F8?  Currently kernel-xen 2.6.21-2950 and xen 3.1.0-13.

Rich.

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