2015-08-29 22:50:17

by Jeffrey Merkey

[permalink] [raw]
Subject: igmp broadcast storm Red Hat EL7 3.1 Kernel

When installing Centos 7 running kernel 3.1 (Centos 7 distro) the
system generates an igmp broadcast storm which locks up and knocks
down a Century Link DSL router. Powering the router off clears the
broadcast storm.

The bug is kernel related and resembles very closely another bug seen
about 10 years ago with Caldera's distro's on 2.4. The bug occurs on
the ia32 beta build. The bug DOES NOT exist in the 64 bit x86_64
versions. I will attempt to debug it further since I have my own
debugger and try to run it down and provide more info.

Jeff


2015-08-31 16:48:34

by Cong Wang

[permalink] [raw]
Subject: Re: igmp broadcast storm Red Hat EL7 3.1 Kernel

(Cc'ing netdev)

On Sat, Aug 29, 2015 at 3:50 PM, Jeffrey Merkey <[email protected]> wrote:
> When installing Centos 7 running kernel 3.1 (Centos 7 distro) the
> system generates an igmp broadcast storm which locks up and knocks
> down a Century Link DSL router. Powering the router off clears the
> broadcast storm.
>
> The bug is kernel related and resembles very closely another bug seen
> about 10 years ago with Caldera's distro's on 2.4. The bug occurs on
> the ia32 beta build. The bug DOES NOT exist in the 64 bit x86_64
> versions. I will attempt to debug it further since I have my own
> debugger and try to run it down and provide more info.
>

A reproducer and/or bisect would help a lot.

Thanks.

2015-08-31 18:10:30

by Jeffrey Merkey

[permalink] [raw]
Subject: Re: igmp broadcast storm Red Hat EL7 3.1 Kernel

I was able to reproduce it last night with 2.6.32 on Centos 6.3 so it
does not seem confined to just the 3.X tree. I think this is
something that's been lurking in the kernel for years and just has a
hard time showing up. Bugs that go away on their own come back on
their own.

I got a trace of the traffic but need one of the os. I'll attempt to
get a trace of this again since I seem to be able to reproduce it by
routing NetFlix traffic through the router while I am streaming live
videos on Linux.

I will setup the system to trap the bug and post the traces.

Jeff


On 8/31/15, Cong Wang <[email protected]> wrote:
> (Cc'ing netdev)
>
> On Sat, Aug 29, 2015 at 3:50 PM, Jeffrey Merkey <[email protected]>
> wrote:
>> When installing Centos 7 running kernel 3.1 (Centos 7 distro) the
>> system generates an igmp broadcast storm which locks up and knocks
>> down a Century Link DSL router. Powering the router off clears the
>> broadcast storm.
>>
>> The bug is kernel related and resembles very closely another bug seen
>> about 10 years ago with Caldera's distro's on 2.4. The bug occurs on
>> the ia32 beta build. The bug DOES NOT exist in the 64 bit x86_64
>> versions. I will attempt to debug it further since I have my own
>> debugger and try to run it down and provide more info.
>>
>
> A reproducer and/or bisect would help a lot.
>
> Thanks.
>