[dm-devel] Bug in dm_any_congested?

[Zdenek Kabelac]

Dne 10.11.2015 v 14:14 Boštjan Škufca @ Teon.si napsal(a):
> Hi all,
>
> (I am not sure if this is the right address for this bug, but dm_* is
> the first function listed in trace)
>
> this happened when I tried dd-ing LV, which resides on RAID10 sw
> storage, to network via netcat. The actual user-visible manifestation
> was segfault of dd that was used for reading.
>
> On first request the error reported was "unable to handle kernel NULL
> pointer dereference...", but on subsequent tries this changed to
> "general protection fault", see below.
>
> HW is a bit dated, but had no problems with it up to now, and SW raid
> is used here. Kernel was 4.2.4.
>
> Is this the right mlist for such bug?

Hi

Yes the issue is known - but source is not fully known.
I've opened public BZ: https://bugzilla.redhat.com/1279941
There is some potential fix - but unclear what it solves:
http://git.kernel.org/linus/ad5f498f610

Regards

Zdenek