linux-kernel - RE: [PATCH] Fix kexec abort due to IPI from panic().

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: <5C4C569E8A4B9B42A84A977CF070A35B2C09821A9E@USINDEVS01.corp.hds.com>
Date:	Fri, 17 Sep 2010 11:08:48 -0400
From:	Seiji Aguchi <seiji.aguchi@....com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"xiyou.wangcong@...il.com" <xiyou.wangcong@...il.com>,
	"paulmck@...ux.vnet.ibm.com" <paulmck@...ux.vnet.ibm.com>,
	"simon.kagstrom@...insight.net" <simon.kagstrom@...insight.net>,
	"kexec@...ts.infradead.org" <kexec@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Satoru Moriya <satoru.moriya@....com>,
	"dle-develop@...ts.sourceforge.net" 
	<dle-develop@...ts.sourceforge.net>
Subject: RE: [PATCH] Fix kexec abort due to IPI from panic().

Hi Eric,

Thank you for your quick response!

>Disabling interrupts is fine,

Thanks!

>However that call to kmsg_dump(KMSG_DUMP_KEXEC) is a bug as it introduces locks 
>into a path that should not be taking locks.

I'd like to find a way that kexec coexists with kmsg_dump(KMSG_DUMP_KEXEC) because 
kmsg_dump is a useful troubleshooting feature as well.

So, I will improve kmsg_dump(KMSG_DUMP_KEXEC) if there are some bugs.
Could you please let me know your concern?
It is helpful for me if you have an example scenario kexec fails.

>Nothing in the crash_kexec path should even have the option of blocking.

Do you mean I need to change kmsg_dump(KMSG_DUMP_KEXEC) to lockless?

Seiji
--
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/