Re: Trying to unmap invalid handle! pending_idx: @ drivers/net/xen-netback/netback.c:998 causes kernel panic/reboot

[Zoltan Kiss <zoltan.kiss@citrix.com>]

On 14/07/14 13:14, Armin Zentai wrote:
> Hi!
>
> On 14/07/14 13:54, Zoltan Kiss wrote:
>> Hi,
>>
>> Based on the stack trace I think the guest sends packet with more than
>> MAX_SKB_SLOTS slots, and one slot's grant mapping operation goes wrong.
>> Then the error handling screws up the internal bookkeeping of pending
>> slots, and tries to unmap something that is not mapped. Unfortunately it
>> is quite complicated to emulate grant mapping failures in a predictable
>> way.
>> Armin, if we provide some patches (hopefully with a solution, but at
>> least with some additional logging), would you be able to compile and
>> verify it?
>
> I can compile and install it, the verification may take a few days.
> We're building up a test system, and try to test with outgoing traffic.
> If you have any advice, about how to test the new kernel, please share
> with me (I mean large pps, or large bandwidth is the better, or try to
> update/downgrade the GPLPV drivers to a specific version).
>
> I'm setting the loglevel to DBG.

Also, if you have your vmlinux file, can you please run the following:

addr2line -e <your vmlinux file> ffffffffa02622fc

That would hopefully point out where xenvif_idx_unmap were called in 
check_gop, as it has 3 call sites.

Zoli