Date:   Tue, 13 Sep 2022 10:31:14 +0200
From:   Sergio Paracuellos <sergio.paracuellos@...il.com>
To:     Lorenzo Bianconi <lorenzo@...nel.org>
Cc:     Arınç ÜNAL <arinc.unal@...nc9.com>,
        netdev <netdev@...r.kernel.org>, paulmck@...nel.org
Subject: Re: mtk_eth_soc for mt7621 won't work after 6.0-rc1

Hi Lorenzo,

On Tue, Sep 13, 2022 at 5:32 AM Sergio Paracuellos
<sergio.paracuellos@...il.com> wrote:
>
> Hi Lorenzo,
>
> On Mon, Sep 12, 2022 at 10:30 PM Lorenzo Bianconi <lorenzo@...nel.org> wrote:
> >
> > > Hi Lorenzo,
> > >
> > > On 12.09.2022 21:01, Lorenzo Bianconi wrote:
> > > > > > Ethernet for MT7621 SoCs no longer works after changes introduced to
> > > > > > mtk_eth_soc with 6.0-rc1. Ethernet interfaces initialise fine. Packets are
> > > > > > sent out from the interface fine but won't be received on the interface.
> > > > > >
> > > > > > Tested with MT7530 DSA switch connected to gmac0 and ICPlus IP1001 PHY
> > > > > > connected to gmac1 of the SoC.
> > > > > >
> > > > > > Last working kernel is 5.19. The issue is present on 6.0-rc5.
> > > > > >
> > > > > > Arınç
> > > > >
> > > > > Hi Arınç,
> > > > >
> > > > > thx for testing and reporting the issue. Can you please identify
> > > > > the offending commit running git bisect?
> > > > >
> > > > > Regards,
> > > > > Lorenzo
> > > >
> > > > Hi Arınç,
> > > >
> > > > just a small update. I tested a mt7621 based board (Buffalo WSR-1166DHP) with
> > > > OpenWrt master + my mtk_eth_soc series and it works fine. Can you please
> > > > provide more details about your development board/environment?
> > >
> > > I've got a GB-PC2, Sergio has got a GB-PC1. We both use Neil's gnubee-tools
> > > which makes an image with filesystem and any Linux kernel of choice with
> > > slight modifications (maybe not at all) on the kernel.
> > >
> > > https://github.com/neilbrown/gnubee-tools
> > >
> > > Sergio experiences the same problem on GB-PC1.
> >
> > ack, can you please run git bisect in order to identify the offending commit?
> > What is the latest kernel version that is working properly? 5.19.8?
>
> I'll try to get time today to properly bisect and identify the
> offending commit. I get a working platform with 5.19.8, yes but with
> v6-rc-1 my network is totally broken.

+ [cc: Paul E. McKenney <paulmck@...nel.org> as commit author]

Ok, so I have bisected the issue to:
1cf1144e8473e8c3180ac8b91309e29b6acfd95f] rcu-tasks: Be more patient
for RCU Tasks boot-time testing

This is the complete bisect log:

$ git bisect log
git bisect start
# good: [70cb6afe0e2ff1b7854d840978b1849bffb3ed21] Linux 5.19.8
git bisect good 70cb6afe0e2ff1b7854d840978b1849bffb3ed21
# bad: [568035b01cfb107af8d2e4bd2fb9aea22cf5b868] Linux 6.0-rc1
git bisect bad 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
# good: [3d7cb6b04c3f3115719235cc6866b10326de34cd] Linux 5.19
git bisect good 3d7cb6b04c3f3115719235cc6866b10326de34cd
# bad: [b44f2fd87919b5ae6e1756d4c7ba2cbba22238e1] Merge tag
'drm-next-2022-08-03' of git://anongit.freedesktop.org/drm/drm
git bisect bad b44f2fd87919b5ae6e1756d4c7ba2cbba22238e1
# bad: [526942b8134cc34d25d27f95dfff98b8ce2f6fcd] Merge tag
'ata-5.20-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata
git bisect bad 526942b8134cc34d25d27f95dfff98b8ce2f6fcd
# good: [2e7a95156d64667a8ded606829d57c6fc92e41df] Merge tag
'regmap-v5.20' of
git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap
git bisect good 2e7a95156d64667a8ded606829d57c6fc92e41df
# good: [c013d0af81f60cc7dbe357c4e2a925fb6738dbfe] Merge tag
'for-5.20/block-2022-07-29' of git://git.kernel.dk/linux-block
git bisect good c013d0af81f60cc7dbe357c4e2a925fb6738dbfe
# bad: [aad26f55f47a33d6de3df65f0b18e2886059ed6d] Merge tag 'docs-6.0'
of git://git.lwn.net/linux
git bisect bad aad26f55f47a33d6de3df65f0b18e2886059ed6d
# good: [c2a24a7a036b3bd3a2e6c66730dfc777cae6540a] Merge tag
'v5.20-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
git bisect good c2a24a7a036b3bd3a2e6c66730dfc777cae6540a
# bad: [34bc7b454dc31f75a0be7ee8ab378135523d7c51] Merge branch
'ctxt.2022.07.05a' into HEAD
git bisect bad 34bc7b454dc31f75a0be7ee8ab378135523d7c51
# bad: [e72ee5e1a866b85cb6c3d4c80a1125976020a7e8] rcu-tasks: Use
delayed_work to delay rcu_tasks_verify_self_tests()
git bisect bad e72ee5e1a866b85cb6c3d4c80a1125976020a7e8
# good: [f90f19da88bfe32dd1fdfd104de4c0526a3be701] rcu-tasks: Make RCU
Tasks Trace stall warning handle idle offline tasks
git bisect good f90f19da88bfe32dd1fdfd104de4c0526a3be701
# good: [dc7d54b45170e1e3ced9f86718aa4274fd727790] rcu-tasks: Pull in
tasks blocked within RCU Tasks Trace readers
git bisect good dc7d54b45170e1e3ced9f86718aa4274fd727790
# good: [e386b6725798eec07facedf4d4bb710c079fd25c] rcu-tasks:
Eliminate RCU Tasks Trace IPIs to online CPUs
git bisect good e386b6725798eec07facedf4d4bb710c079fd25c
# good: [eea3423b162d5d5cdc08af23e8ee2c2d1134fd07] rcu-tasks: Update comments
git bisect good eea3423b162d5d5cdc08af23e8ee2c2d1134fd07
# bad: [1cf1144e8473e8c3180ac8b91309e29b6acfd95f] rcu-tasks: Be more
patient for RCU Tasks boot-time testing
git bisect bad 1cf1144e8473e8c3180ac8b91309e29b6acfd95f
# first bad commit: [1cf1144e8473e8c3180ac8b91309e29b6acfd95f]
rcu-tasks: Be more patient for RCU Tasks boot-time testing

I don't really understand the relationship with my broken network
issue. I am using debian buster and the effect I see is that when the
network interface becomes up it hangs waiting for a "task running to
raise network interfaces". After about one minute the system boots,
the login prompt is shown but I cannot configure at all network
interfaces: dhclient does not respond and manually ifconfig does not
help also:

root@...bee:~#
root@...bee:~# dhclient ethblack
^C
root@...bee:~# ifconfig ethblack 192.168.1.101
root@...bee:~# ping 19^C
root@...bee:~# ping 192.168.1.47
PING 192.168.1.47 (192.168.1.47) 56(84) bytes of data.
^C
--- 192.168.1.47 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 120ms

I have tried to revert the bad commit directly in v6.0-rc1 but
conflicts appeared with the git revert command in
'kernel/rcu/tasks.h', so I am not sure what I can do now.

Thanks,
    Sergio Paracuellos

>
> Thanks,
>     Sergio Paracuellos
>
> >
> > Regards,
> > Lorenzo
> >
> > >
> > > Arınç

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