Re: [PATCH 4.9 00/35] 4.9.265-rc1 review

Guenter Roeck
2021-04-05T23:52:03Z

On Mon, Apr 05, 2021 at 10:56:29AM -0700, Guenter Roeck wrote:
> On Mon, Apr 05, 2021 at 10:53:35AM +0200, Greg Kroah-Hartman wrote:
> > This is the start of the stable review cycle for the 4.9.265 release.
> > There are 35 patches in this series, all will be posted as a response
> > to this one. If anyone has any issues with these being applied, please
> > let me know.
> >
> > Responses should be made by Wed, 07 Apr 2021 08:50:09 +0000.
> > Anything received after that time might be too late.
> >
>
> Build results:
> total: 163 pass: 163 fail: 0
> Qemu test results:
> total: 383 pass: 382 fail: 1
> Failed tests:
> parisc:generic-32bit_defconfig:smp:net,pcnet:scsi[53C895A]:rootfs
>
> In the failing test, the network interfcace instantiates but fails to get
> an IP address. This is not a new problem but a new test. For some reason
> it only happens with this specific network interface, this specific SCSI
> controller, and with v4.9.y. No reason for concern; I'll try to track down
> what is going on.
>

Interesting. The problem affects all kernels up to and including
v4.19.y. Unlike I thought initially, the problem is not associated
with the SCSI controller (that was coincidental) but with pcnet
Ethernet interfaces. It has been fixed in the upstream kernel with
commit 518a2f1925c3 ("dma-mapping: zero memory returned from
dma_alloc_*"). This patch does not apply cleanly to any of the
affected kernels. I backported part of it to v4.19.y and v4.9.y
and confirmed that it fixes the problem in those branches.

Question is what we should do: try to backport 518a2f1925c3 to v4.19.y
and earlier, or stop testing against this specific problem.

Any thoughts ?

Thanks,
Guenter