Re: [PATCH] Revert "x86/apic/x2apic: Implement IPI shorthands support"

[Baoquan He]

On 01/09/23 at 10:59pm, Thomas Gleixner wrote:
> On Tue, Dec 20 2022 at 13:34, Baoquan He wrote:
> > This reverts commit 43931d350f30c6cd8c2f498d54ef7d65750abc92.
> >
> > On kvm guest with 4 cpus deployed, when adding 'nr_cpus=2' to normal
> > kernel's cmdline, and triggering crash to jump to kdump kernel, kdump
> > kernel will stably hang. Reverting commit 43931d350f30 ("x86/apic/x2apic:
> > Implement IPI shorthands support") can fix it.
> 
> Is there any output on the early console or hangs it silently?
> 
> If the latter, can you attach GDB to the guest and figure out where it
> is stuck?

No any output on the ealry console. I will try gdb debugging. Thanks.