Subject: Re: [PATCH 01/20 -v5] printk - dont wakeup klogd with interrupts
	disabled
From: Daniel Walker <dwalker@mvista.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Christoph Hellwig <hch@infradead.org>,
       Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       Gregory Haskins <ghaskins@novell.com>,
       Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
       Thomas Gleixner <tglx@linutronix.de>, Tim Bird <tim.bird@am.sony.com>,
       Sam Ravnborg <sam@ravnborg.org>, "Frank Ch. Eigler" <fche@redhat.com>,
       Jan Kiszka <jan.kiszka@siemens.com>, John Stultz <johnstul@us.ibm.com>,
       Arjan van de Ven <arjan@infradead.org>,
       Steven Rostedt <srostedt@redhat.com>
In-Reply-To: <Pine.LNX.4.58.0801231213430.12932@gandalf.stny.rr.com>
References: <20080123160236.969334052@goodmis.org>
	 <20080123160441.236562634@goodmis.org>
	 <1201107978.13596.16.camel@imap.mvista.com>
	 <Pine.LNX.4.58.0801231213430.12932@gandalf.stny.rr.com>
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Date: Wed, 23 Jan 2008 09:43:05 -0800
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> 	if (wake_klogd && !runqueue_is_locked())
> 		wake_up_klogd();
> 
> This probably is the cleanest solution since it simply prevents the
> deadlock from occurring.

Do you really need to call it with the runqueue lock held .. There are
other issue with the calls at that level.. For instance in -rt these
call can actually hang the system in the console laying from inside
printk (something I reported more than 6 months ago) .. It would be
better to move them around the scheduler rather than inside it..

Daniel

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