Re: [PATCH net] ipv6: don't stop backtracking in fib6_lookup_1 if subtree does not match

OK, I went back to kernel where I had the ipv6 sadr lookup in cache problem.
There I patched the ip6_fib.c.
Patch works !!

The hang problem in 3.8.0-28 has lower priority for me. Maybe I'll check current -net-next later. Don't hold your breath.

Now this patch should go mainline and older kernels, I think.
What is the next step?

Teco


Op 9 aug. 2013, om 16:57 heeft Hannes Frederic Sowa [off-list ref] het volgende geschreven:

On Fri, Aug 09, 2013 at 04:40:03PM +0200, Teco Boot wrote:

quoted

Op 9 aug. 2013, om 16:19 heeft Hannes Frederic Sowa [off-list ref] het volgende geschreven:

quoted

On Fri, Aug 09, 2013 at 04:12:20PM +0200, Teco Boot wrote:

quoted

Double checked, it works. Tested with Common Open Research Emulator (CORE, from NRL).

=== But ===

I had some problems with CORE. Could be me, new kernel version, the patch, CORE using network namespaces, or combination of that. sudo hangs, reboot hangs, ip address show hangs.
With ps -ef, I see some suspected items:
root      4858  4161  0 15:57 ?        00:00:00 /sbin/ip -6 addr flush dev eth0
root      4859     2  0 15:57 ?        00:00:00 [kworker/0:3]
In the emulation I use, there was no IPv6.

I'll try to figure out if it is CORE & netns in combination with patch. Or just the patch. Or just the new kernel.
Just to speed up, any idea where to look for?

echo t > /proc/sysrq-trigger and check dmesg while the system hangs. Maybe you
have to use a serial console and send the sysrq over keyboard/break.

System was still running.
Cleared dmesg, silence.
Then performed echo t > /proc/sysrq-trigger.
Quite large dump.
Afterwards, silence again.

I think you are experience high fib6_gc_lock contention (and while the lock is
held you also hold rtnl_lock, which let's all the other processes hang).
Please test if these patches make things more smooth for you:

https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=2ac3ac8f86f2fe065d746d9a9abaca867adec577
https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=49a18d86f66d33a20144ecb5a34bba0d1856b260

Thanks,

 Hannes