Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424048AbWKIPYr (ORCPT ); Thu, 9 Nov 2006 10:24:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1424031AbWKIPYr (ORCPT ); Thu, 9 Nov 2006 10:24:47 -0500 Received: from mail.gmx.net ([213.165.64.20]:33666 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S1424048AbWKIPYq (ORCPT ); Thu, 9 Nov 2006 10:24:46 -0500 X-Authenticated: #14349625 Subject: Re: 2.6.19-rc5 breaks klogd 1.4.1 From: Mike Galbraith To: Andrew Morton Cc: John Wendel , linux-kernel@vger.kernel.org In-Reply-To: <1163067064.6145.4.camel@Homer.simpson.net> References: <4552BB55.9090400@comcast.net> <20061108224153.4ed2e581.akpm@osdl.org> <4552D4B4.5020505@comcast.net> <20061108233517.7cc1db12.akpm@osdl.org> <1163067064.6145.4.camel@Homer.simpson.net> Content-Type: text/plain Date: Thu, 09 Nov 2006 16:25:26 +0100 Message-Id: <1163085926.6087.17.camel@Homer.simpson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.6.0 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1488 Lines: 36 On Thu, 2006-11-09 at 11:11 +0100, Mike Galbraith wrote: > On Wed, 2006-11-08 at 23:35 -0800, Andrew Morton wrote: > > > And, predictably, reads from /proc/kmsg aren't blocking. > > > > I can't see what might have caused that. Are you sure that 2.6.19-rc4 was > > OK? And are you sure that nothing else has changed on that system? > > Here, both rc4 and rc5 do the same if printk is configured out. Well duh, of course it does. Testing and _then_ looking at the source was not the correct order in this case :) > Why do we have a /proc/ksmg when nothing can get to it? The sensible thing seemed to be to whack it, but when I did that, klogd just switched interfaces, and proceeded to eat 100% cpu doing syslog(0x2, 0xb7fc0008, 0x1ffff) instead. Leaving it in place, but making it block to simulate an empty buffer works fine, but seems kinda cheezy. Whacking /proc/kmsg, and making sys_syslog() block on read to simulate the empty buffer seemed much better, but SuSE's boot scripts hang when they try to create /var/log/boot.msg ala /sbin/klogd -s -o -n -f /var/log/boot.msg. That seems to work now only because there is always something there to grab. The correct answer seems to be "fix klogd, or don't disable printk". -Mike - 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/