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From: Joerg Platte <lists@naasa.net>
To: "Günther Starnberger" <gst@sysfrog.org>
Cc: "Pekka Enberg" <penberg@cs.helsinki.fi>, linux-kernel@vger.kernel.org
Subject: Re: Userspace process may be able to DoS kernel
Date: Fri, 13 Oct 2006 15:24:31 +0200	[thread overview]
Message-ID: <200610131524.31772.lists@naasa.net> (raw)
In-Reply-To: <474c7c2f0610121325j23320d36i20c71ccaa04645d9@mail.gmail.com>

Am Donnerstag, 12. Oktober 2006 22:25 schrieb Günther Starnberger:
Hi,

> According to [1] there are several anti-debugging techniques used in
> Skype. I.e. if it notices some sort of debugger it will crash (on
> purpose).

I know. I just wanted to know if I'm able to catch a blocking system call...

> [1]
> www.blackhat.com/presentations/bh-europe-06/bh-eu-06-biondi/bh-eu-06-biondi
>-up.pdf -

Here is my output from a longer lockup today. I can confirm, that pings and 
system time are not affected by the lockup. I didn't try to log in via ssh 
but I think that will not work, too.

Oct 13 15:11:08 localhost kernel: BUG: soft lockup detected on CPU#0!
Oct 13 15:11:08 localhost kernel:  [<c012f9d5>] softlockup_tick+0x89/0xa4
Oct 13 15:11:08 localhost kernel:  [<c011b458>] update_process_times+0x35/0x57
Oct 13 15:11:08 localhost kernel:  [<c01052c9>] timer_interrupt+0x35/0x64
Oct 13 15:11:08 localhost kernel:  [<c012fc13>] handle_IRQ_event+0x23/0x49
Oct 13 15:11:08 localhost kernel:  [<c012fe45>] __do_IRQ+0x7b/0xde
Oct 13 15:11:08 localhost kernel:  [<c010438a>] do_IRQ+0x40/0x4d
Oct 13 15:11:08 localhost kernel:  [<c0102d82>] common_interrupt+0x1a/0x20
Oct 13 15:11:08 localhost kernel:  [<c01e3f0e>] acpi_pm_read+0x7/0xf
Oct 13 15:11:09 localhost kernel:  [<c011a53d>] getnstimeofday+0x2b/0xac
Oct 13 15:11:09 localhost kernel:  [<c01226f4>] sys_clock_gettime+0x42/0x7e
Oct 13 15:11:09 localhost kernel:  [<c0102bfb>] syscall_call+0x7/0xb
Oct 13 15:11:09 localhost kernel: BUG: soft lockup detected on CPU#0!
Oct 13 15:11:09 localhost kernel:  [<c012f9d5>] softlockup_tick+0x89/0xa4
Oct 13 15:11:09 localhost kernel:  [<c011b458>] update_process_times+0x35/0x57
Oct 13 15:11:09 localhost kernel:  [<c01052c9>] timer_interrupt+0x35/0x64
Oct 13 15:11:09 localhost kernel:  [<c012fc13>] handle_IRQ_event+0x23/0x49
Oct 13 15:11:09 localhost kernel:  [<c012fe45>] __do_IRQ+0x7b/0xde
Oct 13 15:11:09 localhost kernel:  [<c010438a>] do_IRQ+0x40/0x4d
Oct 13 15:11:09 localhost kernel:  [<c0102d82>] common_interrupt+0x1a/0x20
Oct 13 15:11:09 localhost kernel:  [<c01e3f0e>] acpi_pm_read+0x7/0xf
Oct 13 15:11:09 localhost kernel:  [<c011a53d>] getnstimeofday+0x2b/0xac
Oct 13 15:11:09 localhost kernel:  [<c01226f4>] sys_clock_gettime+0x42/0x7e
Oct 13 15:11:09 localhost kernel:  [<c0102bfb>] syscall_call+0x7/0xb

Typically I have two lockups, a first longer one and then a shorter one. Then 
everything runs without any problems. 

regards,
Jörg

-- 
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  reply	other threads:[~2006-10-13 13:24 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-11 16:54 Userspace process may be able to DoS kernel Günther Starnberger
2006-10-12  6:02 ` Joerg Platte
2006-10-12  6:49   ` Willy Tarreau
2006-10-12 10:54     ` Joerg Platte
2006-10-12 11:30   ` Pekka Enberg
2006-10-12 11:41     ` Joerg Platte
2006-10-12 11:57       ` Pekka Enberg
2006-10-12 20:11         ` Joerg Platte
2006-10-12 20:25           ` Günther Starnberger
2006-10-13 13:24             ` Joerg Platte [this message]
2006-10-12 15:51 ` Lee Revell
2006-10-12 16:55   ` Günther Starnberger
2006-10-12 17:05     ` Lee Revell
2006-10-12 20:30   ` Günther Starnberger
2006-10-12 20:37     ` Lee Revell
2006-10-12 15:56 ` Lee Revell
2006-10-12 16:10   ` Jan Engelhardt
2006-10-12 16:19     ` Lee Revell
2006-10-12 22:02       ` Jan Engelhardt
     [not found] ` <200611100803.03958.lists@naasa.net>
     [not found]   ` <20061109231958.f18cd1ef.akpm@osdl.org>
2006-11-11 12:29     ` Joerg Platte
2006-11-11 12:39       ` Arjan van de Ven
2006-11-11 13:15         ` Joerg Platte

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