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

[Oliver Sang]

hi, Peter Zijlstra,

On Mon, Sep 09, 2024 at 12:56:23PM +0200, Peter Zijlstra wrote:
> 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?

we did the same test upon commit
6b01e5a8c1161 (peterz-queue/locking/urgent) jump_label: Fix static_key_slow_dec() yet again

the issue cannot be reproduced. thanks