From: Thomas Gleixner <tglx@linutronix.de>
To: Sean Christopherson <seanjc@google.com>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org,
"Guilherme G . Piccoli" <gpiccoli@igalia.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 1/2] x86/crash: Disable virt in core NMI crash handler to avoid double list_add
Date: Thu, 12 May 2022 17:48:58 +0200 [thread overview]
Message-ID: <87k0aqvjit.ffs@tglx> (raw)
In-Reply-To: <Yn0WPBGGI4VcbM4S@google.com>
On Thu, May 12 2022 at 14:14, Sean Christopherson wrote:
> On Thu, May 12, 2022, Thomas Gleixner wrote:
> diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
> index 4e3a839ae146..808d3e75fb2d 100644
> --- a/arch/x86/kernel/reboot.c
> +++ b/arch/x86/kernel/reboot.c
> @@ -896,7 +896,11 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback)
> msecs--;
> }
>
> - /* Leave the nmi callback set */
> + /*
> + * Leave the nmi callback set, shootdown is a one-time thing. Clearing
> + * the callback could result in a NULL pointer dereference if a CPU
> + * (finally) responds after the timeout expires.
> + */
Good point!
next prev parent reply other threads:[~2022-05-12 15:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-11 23:43 [PATCH 0/2] x86/crash: Fix double list_add nmi_shootdown bug Sean Christopherson
2022-05-11 23:43 ` [PATCH 1/2] x86/crash: Disable virt in core NMI crash handler to avoid double list_add Sean Christopherson
2022-05-12 9:14 ` Vitaly Kuznetsov
2022-05-12 10:51 ` Thomas Gleixner
2022-05-12 14:14 ` Sean Christopherson
2022-05-12 14:35 ` Sean Christopherson
2022-05-12 15:48 ` Thomas Gleixner [this message]
2022-05-11 23:43 ` [PATCH 2/2] x86/reboot: Disable virtualization in an emergency if SVM is supported Sean Christopherson
2022-05-12 8:37 ` Vitaly Kuznetsov
2022-05-12 10:57 ` Thomas Gleixner
2022-05-12 14:39 ` Sean Christopherson
2022-05-12 15:47 ` Thomas Gleixner
2022-05-13 11:10 ` [PATCH] x86/nmi: Make register_nmi_handler() more robust Thomas Gleixner
2022-05-15 11:37 ` Thomas Gleixner
2022-05-15 11:39 ` [PATCH V2] " Thomas Gleixner
2022-05-17 7:34 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
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