Re: BUG: kernel NULL pointer dereference, address: 00000004 - mas_update_gap

[Liam Howlett]

* Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> [220516 02:35]:
> While running LTP sched tests on i386 the following kernel BUG noticed on
> Linux next-20220513 [1].
> 
...

> Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
> 
> metadata:
>   git_ref: master
>   git_repo: ''
>   git_sha: 1e1b28b936aed946122b4e0991e7144fdbbfd77e
>   git_describe: next-20220513
>   kernel_version: 5.18.0-rc6
>   kernel-config: https://builds.tuxbuild.com/296PiI1oM7N6Vk7m9lxuipmXW7B/config
>   build-url: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next/-/pipelines/538244935
>   artifact-location: https://builds.tuxbuild.com/296PiI1oM7N6Vk7m9lxuipmXW7B
>   toolchain: gcc-11
> 
> --
> Linaro LKFT
> https://lkft.linaro.org
> 
> [1] https://lkft.validation.linaro.org/scheduler/job/5021335#L1718


I was able to reproduce this issue with ltp running:
"./runltp -p -q -f sched"

I have sent a fix out [1] that allows the test to execute on i386 qemu.

Thanks,
Liam

1. https://lore.kernel.org/linux-mm/20220517152209.3486724-1-Liam.Howlett@xxxxxxxxxx/