Subject: Re: stable-rc/linux-5.18.y bisection: baseline.login on panda

From: Lukas Wunner <[email-masked]>
Date: Thu, 25 Aug 2022 06:21:06 +0200

On Wed, Aug 24, 2022 at 11:47:03PM +0100, Mark Brown wrote:
> On Wed, Aug 24, 2022 at 01:22:12PM -0700, KernelCI bot wrote:
> The KernelCI bisection bot identified 7eea9a60703ca ("usbnet: smsc95xx:
> Forward PHY interrupts to PHY driver to avoid polling") as causing a
> boot regression on Panda in v5.18.  The board stops detecting a link
> which breks NFS boot:
> 
> <6>[    4.953613] smsc95xx 2-1.1:1.0 eth0: register 'smsc95xx' at usb-4a064c00.ehci-1.1, smsc95xx USB 2.0 Ethernet, 02:03:01:8c:13:b0
> <6>[    5.032928] smsc95xx 2-1.1:1.0 eth0: hardware isn't capable of remote wakeup
> <6>[    5.044036] smsc95xx 2-1.1:1.0 eth0: Link is Down
> <6>[   25.053924] Waiting up to 100 more seconds for network.
> <6>[   45.074005] Waiting up to 80 more seconds for network.
> <6>[   65.093933] Waiting up to 60 more seconds for network.
> <6>[   85.123992] Waiting up to 40 more seconds for network.
> <6>[  105.143951] Waiting up to 20 more seconds for network.
> <5>[  125.084014] Sending DHCP requests ...... timed out!

Looks like v5.19 boots fine (with the offending commit), so only
v5.18-stable and v5.15-stable are affected:

https://storage.kernelci.org/stable-rc/linux-5.19.y/v5.19.3-366-g32f80a5b58e2/arm/multi_v7_defconfig/gcc-10/lab-baylibre/baseline-panda.html

The offending commit was a new feature introduced in v5.19,
it deliberately wasn't tagged for stable.  Aggressively
backporting such new features always carries a risk of
regressions.

Off the cuff I don't see that a prerequisite commit is missing
in stable kernels.  So just reverting the offending commit in
v5.18-stable and v5.15-stable (but not in v5.19-stable) might
be the simplest solution.

Thanks,

Lukas