linux-kernel - Re: [V3 PATCH 2/4] panic/x86: Allow cpus to save registers even if they are looping in NMI context

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150820231816.GH3161@worktop.event.rightround.com>
Date:	Fri, 21 Aug 2015 01:18:16 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Hidehiro Kawai <hidehiro.kawai.ez@...achi.com>
Cc:	Jonathan Corbet <corbet@....net>, Ingo Molnar <mingo@...nel.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Vivek Goyal <vgoyal@...hat.com>, linux-doc@...r.kernel.org,
	x86@...nel.org, kexec@...ts.infradead.org,
	linux-kernel@...r.kernel.org, Michal Hocko <mhocko@...nel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Subject: Re: [V3 PATCH 2/4] panic/x86: Allow cpus to save registers even if
 they are looping in NMI context

On Thu, Aug 06, 2015 at 02:45:43PM +0900, Hidehiro Kawai wrote:
> When cpu-A panics on NMI just after cpu-B has panicked, cpu-A loops
> infinitely in NMI context.  Especially for x86, cpu-B issues NMI IPI
> to other cpus to save their register states and do some cleanups if
> kdump is enabled, but cpu-A can't handle the NMI and fails to save
> register states.
> 
> To solve thie issue, we wait for the timing of the NMI IPI, then
> call the NMI handler which saves register states.

Sorry, I don't follow, what?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/