linux-kernel - Re: [PATCH] kexec: set prstatus.pr_pid to cpu id when current->pid is 0

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: <m1d3u0un7b.fsf@fess.ebiederm.org>
Date:	Tue, 03 Aug 2010 01:15:04 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Hui Zhu <teawater@...il.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	WANG Cong <xiyou.wangcong@...il.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Simon Kagstrom <simon.kagstrom@...insight.net>,
	kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
	gdb@...rceware.org
Subject: Re: [PATCH] kexec: set prstatus.pr_pid to cpu id when current->pid is  0

Hui Zhu <teawater@...il.com> writes:

> On Tue, Aug 3, 2010 at 15:37, Eric W. Biederman <ebiederm@...ssion.com> wrote:
>> Hui Zhu <teawater@...il.com> writes:
>>
>
> Equal 0 is not a bug, the trouble is a lot of core's pid is same.
>
> This is what gdb say:
> /* Found an old thread with the same id.  It has to be dead,
>        otherwise we wouldn't be adding a new thread with the same id.
>        The OS is reusing this id --- delete it, and recreate a new
>        one.  */

gdb bug compatibility is not a primary goal.  Having an extensible
format and not inventing it totally out of the blue is the goal.

The goal was always that something could post process the output of
the kernel crashdump and create something that is gdb compatible.  It
looks to me like it would take just a moment to strip out all of the
idle threads.

Claiming the pid is the cpu number when the pid is the idle pid gives
you no insulation against duplication, and it looses information.

Eric
--
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/