Re: [Regression][BISECTED] kernel boot hang after 19898ce9cf8a ("wifi: iwlwifi: split 22000.c into multiple files")

[Linux regression tracking (Thorsten Leemhuis)]

[CCing the regression list, netdev, the net maintainers, and Linus;
Johannes and Kalle as well, but just for the record, they afaik are
unavailable]

Hi, Thorsten here, the Linux kernel's regression tracker.

On 07.07.23 10:25, Zhang, Rui wrote:
> 
> I run into a NULL pointer dereference and kernel boot hang after
> switching to latest upstream kernel, and git bisect shows that below
> commit is the first offending commit, and I have confirmed that commit
> 19898ce9cf8a has the issue while 19898ce9cf8a~1 does not.

FWIW, this is the fourth such report about this that I'm aware of.

The first is this one (with two affected users afaics):
https://bugzilla.kernel.org/show_bug.cgi?id=217622

The second is this one:
https://lore.kernel.org/all/CAAJw_Zug6VCS5ZqTWaFSr9sd85k%3DtyPm9DEE%2BmV%3DAKoECZM%2BsQ@xxxxxxxxxxxxxx/

The third:
https://lore.kernel.org/all/9274d9bd3d080a457649ff5addcc1726f08ef5b2.camel@xxxxxxxxxxx/

And in the past few days two people from Fedora land talked to me on IRC
with problems that in retrospective might be caused by this as well.

This many reports about a problem at this stage of the cycle makes me
suspect we'll see a lot more once -rc1 is out. That's why I raising the
awareness of this. Sadly a simple revert of just this commit is not
possible. :-/

Ciao, Thorsten

> commit 19898ce9cf8a33e0ac35cb4c7f68de297cc93cb2 (refs/bisect/bad)
> Author:     Johannes Berg <johannes.berg@xxxxxxxxx>
> AuthorDate: Wed Jun 21 13:12:07 2023 +0300
> Commit:     Johannes Berg <johannes.berg@xxxxxxxxx>
> CommitDate: Wed Jun 21 14:07:00 2023 +0200
> 
>     wifi: iwlwifi: split 22000.c into multiple files
>     
>     Split the configuration list in 22000.c into four new files,
>     per new device family, so we don't have this huge unusable
>     file. Yes, this duplicates a few small things, but that's
>     still much better than what we have now.
>     
>     Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
>     Signed-off-by: Gregory Greenman <gregory.greenman@xxxxxxxxx>
>     Link:
> https://lore.kernel.org/r/20230621130443.7543603b2ee7.Ia8dd54216d341ef1ddc0531f2c9aa30d30536a5d@changeid
>     Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
> 
> I have some screenshots which show that RIP points to iwl_mem_free_skb,
> I can create a kernel bugzilla and attach the screenshots there if
> needed.
> 
> BTW, lspci output of the wifi device and git bisect log attached.
> 
> If any other information needed, please let me know.

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P.S.: for regzbot

#regzbot ^introduced 19898ce9cf8a
#regzbot dup-of:
https://lore.kernel.org/all/a5cdc7f8-b340-d372-2971-0d24b01de217@xxxxxxxxx/