linux-kernel - Re: Magic SysRq SAK does nothing on serial consoles

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Message-ID: <20060901145539.GC4377@ucw.cz>
Date:	Fri, 1 Sep 2006 14:55:39 +0000
From:	Pavel Machek <pavel@...e.cz>
To:	Simon Tatham <anakin@...ox.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Magic SysRq SAK does nothing on serial consoles

Hi!

> Applying the attached patch resolved the problem for me; now when I
> send BREAK-k, the kernel prints `SysRq : SAK', then prints a couple
> of lines indicating that some processes have been killed, and then
> init spawns a new login process as I would expect.
> 
> (The patch is defensively coded, since I wasn't sure whether
> port->info was guaranteeably non-NULL. If it is, the change can be
> even simpler!)

Try to find out if port->info can be NULL; then you should probably
resubmit, cc akpm and rmk. Also see Doc*/SubmittingPatches.

> --- linux-2.6.17.6.orig/include/linux/serial_core.h	2006-07-15 20:00:43.000000000 +0100
> +++ linux-2.6.17.6/include/linux/serial_core.h	2006-08-30 07:55:00.000000000 +0100
> @@ -411,7 +411,7 @@
>  #ifdef SUPPORT_SYSRQ
>  	if (port->sysrq) {
>  		if (ch && time_before(jiffies, port->sysrq)) {
> -			handle_sysrq(ch, regs, NULL);
> +			handle_sysrq(ch, regs, port->info ? port->info->tty : NULL);
>  			port->sysrq = 0;
>  			return 1;
>  		}



-- 
Thanks for all the (sleeping) penguins.
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