Date: Tue, 14 Mar 2006 15:18:12 -0800
From: "Randy.Dunlap" <rdunlap@xenotime.net>
To: Ingo Molnar <mingo@elte.hu>
Cc: rmk+serial@arm.linux.org.uk, linux-kernel@vger.kernel.org
Subject: Re: soft lockup in serial8250_console_write(?)
Message-Id: <20060314151812.2779ed4b.rdunlap@xenotime.net>
In-Reply-To: <20060314214049.GA29536@elte.hu>
References: <20060314134110.3470fc63.rdunlap@xenotime.net>
	<20060314214049.GA29536@elte.hu>
Organization: YPO4
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1019
Lines: 33

On Tue, 14 Mar 2006 22:40:49 +0100 Ingo Molnar wrote:

> 
> * Randy.Dunlap <rdunlap@xenotime.net> wrote:
> 
> > Hi,
> > 
> > (x86_64; 2.6.16-rc6; serial console configured but nothing connected 
> > to the serial port)
> > 
> > I'm seeing an occasional soft lockup, maybe in 
> > serial8250_console_write(). (drivers/serial/8250.c)
> > 
> > This function calls wait_for_xmitr() [inline], which in worst case can 
> > spin for 1.010 seconds.  Could this be the cause of a soft lockup?
> 
> hm, it shouldnt cause that. Could you try the attached patch [which is 
> the next-gen softlockup detector], do you get the message even with that 
> one applied?

5/5 good boots with your new patch.
5/5 soft lockups without it.

Is this scheduled for post-2.6.16 ?

Thanks,
---
~Randy
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/