Subject: Re: Kernel 4.1.12 crash

From: Alexander Duyck <[email-masked]>
Date: Fri, 20 Nov 2015 15:13:08 -0800

On 11/20/2015 05:58 AM, Andrew wrote:
> Hi all.
>
> Today some BRASes on 4.1.12 kernel were crashed.
>
> Here's crash traces: http://pastebin.com/p68hNS8R
> http://pastebin.com/36ieRAM2 http://pastebin.com/3BRTVEB6
>
> On 3.2 kernel same hardware works OK, troubles were noticed after kernel
> upgrade.
>
> What additional info is needed?

Looking over the traces there seem to be two areas called out.

The first is the fib_trie resize BUG_ON that was triggered due to the 
parent and child not being associated.  I think that might be due to 
memory corruption as I cannot find any spots where we are resizing 
without correctly setting up the parent-child relationship of the nodes 
first.

The other spot that is showing up is ppp_shutdown_interface and it's 
related path.  It looks like there are a couple of patches you could try 
back-porting to see if it resolves the issue.  If they do then perhaps 
they should be considered candidates for stable:

8cb775bc0a3 ("ppp: fix device unregistration upon netns deletion")
58a89ecaca5 ("ppp: fix lockdep splat in ppp_dev_uninit()")

- Alex