linux-kernel - Re: kdump hangs up by Sysrq+C trigger in high load.

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: <20081216110949.GB4299@elte.hu>
Date:	Tue, 16 Dec 2008 12:09:49 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Yoshihiro Takahashi <ytakahashi@...aclelinux.com>
Cc:	linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Eduardo Habkost <ehabkost@...hat.com>,
	Huang Ying <ying.huang@...el.com>, kexec@...ts.infradead.org,
	Bernhard Walle <bwalle@...e.de>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: kdump hangs up by Sysrq+C trigger in high load.


* Yoshihiro Takahashi <ytakahashi@...aclelinux.com> wrote:

> Hi.
> 
> kdump hangs up by Sysrq+C trigger once in about 10 times in high load. 
> After the above occurs, kdump cannot collect vmcores with NMI button. 
> When waiting_for_crash_ipi does case more than 0, mdelay seem to make a 
> stall.
> 
> While nmi_shootdown_cpus(), mdelay may not work since interruption is 
> disable.  (ex. when crashing kernel by NMI interruption, all 
> interruption may be disabled.).
> 
> So I think that it should use other way (TSC) instead of mdelay() in 
> nmi_shootdown_cpus().

mdelay uses either the tsc or CPU loops - neither stop while IRQs are 
disabled.

Could you figure out exactly why it hangs in your case?

	Ingo
--
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/