Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 10 Jan 2023 10:24:39 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        kexec@lists.infradead.org
Subject: Re: [PATCH] Revert "x86/apic/x2apic: Implement IPI shorthands
 support"
Message-ID: <Y7zMZ8nCNtSt09kV@fedora>
References: <Y6FJgh3fOYoF0wSV@MiWiFi-R3L-srv>
 <87k01vjrnt.ffs@tglx>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <87k01vjrnt.ffs@tglx>
Precedence: bulk

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.