linux-kernel - debugging a deadlock

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>] [day] [month] [year] [list]

Date:	Fri, 8 Sep 2006 10:36:48 +0300
From:	"Janne Karhunen" <janne.karhunen@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: debugging a deadlock

Hi,

Sometimes you have to do strange things such as trying to debug occasional
deadlock of a system that has been in use for long, long time. So please, no
nasty comments about outdated system with no soft lock-up detection and
such :/

Anyhoo, it appears to be infinite semaphore wait. By modifying the semaphores
to dump stack on LONG wait I managed to get a stack trace. Looks like this:

kernel:    [printk+340/384] [printk+340/384] [show_trace+203/240]
[show_trace+203/240] [show_stack+113/120] [show_registers+223/324]
kernel:    [__down+147/276] [__down_failed+8/12]
[stext_lock+13538/52069] [error_code+16/64] [system_call+66/76]

Umm, this error_code thing is beyond my current knowledge. What's this?
Some sort of assembly-glued exception handling? Any ideas how to figure
out which semaphore this is?

-- 
// Janne
-
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/