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To:     Baoquan He <bhe@redhat.com>, linux-kernel@vger.kernel.org
Cc:     x86@kernel.org, kexec@lists.infradead.org
Subject: Re: [PATCH] Revert "x86/apic/x2apic: Implement IPI shorthands support"
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Date:   Mon, 09 Jan 2023 22:59:18 +0100
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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?

Thanks,

        tglx