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: <20091120012930.GA3985@redhat.com>
Date:	Fri, 20 Nov 2009 02:29:30 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Nick Piggin <npiggin@...e.de>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Roland McGrath <roland@...hat.com>
Subject: Re: Zombie process when ptracing

Hi,

On 11/19, Nick Piggin wrote:
>
> Running recent git kernel, I have a process stuck in Z state
>
> bash          ? 0000000000000000     0  3188   3187 0x00000000
>  ffff88012e24fec8 0000000000000046 0000000000000000 0000000000000012
>  ffff88012e24fec8 ffff88012e24e000 ffff88012e24ffd8 ffff88012e24e000
>  000000000000efc8 ffff88012e24e000 ffff88012ea82090 ffff88012ff78640
> Call Trace:
>  [<ffffffff8124baee>] ? proc_clear_tty+0x5e/0x70
>  [<ffffffff810587a8>] ? exit_ptrace+0xb8/0x140
>  [<ffffffff8105126a>] do_exit+0x58a/0x7c0
>  [<ffffffff810514dd>] do_group_exit+0x3d/0xb0
>  [<ffffffff81051562>] sys_exit_group+0x12/0x20
>  [<ffffffff8100b3eb>] system_call_fastpath+0x16/0x1b
>
> This was after stracing a few test programs.
>
> It also seems to have lost job control (^C) at the same time.

This can happen if the tracer (strace) itself hangs, zombies
should go away once the tracer is killed. Or its ->real_parent
is stopped or hangs...

(I assume you didn't strace /sbin/init)

But,

> Hmm, and the kernel just paniced with an nmi lockup while I was
> trying to get more info.

this probably means we have a kernel bug ;)

If you see a zombie again, could you look at its /ptoc/pid/status?


And of course, which programs did you trace and how? It would be
great if we can reproduce the problem.

Oleg.

--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ