[next] arm: Internal error: Oops: 5 PC is at __read_once_word_nocheck

[Ard Biesheuvel]

On Wed, 9 Mar 2022 at 11:37, Russell King (Oracle)
<linux at armlinux.org.uk> wrote:
>
> On Wed, Mar 09, 2022 at 03:18:12PM +0530, Naresh Kamboju wrote:
> > While boting linux next-20220308 on BeagleBoard-X15 and qemu arm the following
> > kernel crash reported which is CONFIG_KASAN enabled build [1] & [2].
>
> The unwinder is currently broken in linux-next. Please try reverting
> 532319b9c418 ("ARM: unwind: disregard unwind info before stack frame is
> set up")
>

Yeah.

This is the same spot Corentin hit before, where the double
dereference of vsp is not guarded by anything like
get_kernel_nofault(). We should probably fix that, but that doesn't
address the underlying issue, of course.

I'm a bit puzzled, though, that this appears now, and didn't before.

Naresh, I take it you did not see this occurring on earlier linux-nexts?

I'll try to reproduce this, and see if I can make sense of it. In the
mean time, please do the revert Russell suggested, and if that doesn't
help, maybe try a bisect?