Re: [tip:locking/urgent] [jump_label] de752774f3: kernel_BUG_at_arch/x86/kernel/jump_label.c

From: Peter Zijlstra
Date: Mon Sep 09 2024 - 06:56:34 EST


On Mon, Sep 09, 2024 at 11:15:31AM +0200, Peter Zijlstra wrote:
> On Sun, Sep 08, 2024 at 09:06:55PM +0800, kernel test robot wrote:
> >
> >
> > Hello,
> >
> > kernel test robot noticed "kernel_BUG_at_arch/x86/kernel/jump_label.c" on:
> >
> > commit: de752774f38bb766941ed1bf910ba5a9f6cc6bf7 ("jump_label: Fix static_key_slow_dec() yet again")
> > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git locking/urgent
> >
> > in testcase: boot
> >
> > compiler: clang-18
> > test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> >
>
> > The kernel config and materials to reproduce are available at:
> > https://download.01.org/0day-ci/archive/20240908/202409082005.393050e2-oliver.sang@xxxxxxxxx
>
> So the whole thing actually boots and works on my real machine, so I had
> to resort to using this qemu nonsense, as such I did as instructed in
> the reproduce file.
>
> I build the thing using clang-17 (for some reason debian is shitting
> itself trying to install clang-18 on this machine and I don't want to
> spend the day fighting that).
>
> Except, once I do:
>
> bin/lkp qemu -k /usr/src/linux-2.6/tmp-build/arch/x86/boot/bzImage -m /usr/src/linux-2.6/tmp-build/mod/modules.cgz job-script
>
> The whole thing grinds to a halt like so:

Since I'm not able to reproduce, could you please run the thing against:

git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git locking/urgent

and see what that does?