From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757480Ab2FQPJc (ORCPT ); Sun, 17 Jun 2012 11:09:32 -0400 Received: from 1wt.eu ([62.212.114.60]:3318 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757426Ab2FQPJb (ORCPT ); Sun, 17 Jun 2012 11:09:31 -0400 Date: Sun, 17 Jun 2012 17:09:28 +0200 From: Willy Tarreau To: Kay Sievers Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: 3.5 regressions related to printk changes Message-ID: <20120617150928.GJ8450@1wt.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kay, I was failing to get any 3.5-rc[123] kernel to boot on my dockstar (armv5). I finally found some time today to bisect it and found that the responsible commit was : From 7ff9554bb578ba02166071d2d487b7fc7d860d62 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Thu, 3 May 2012 02:29:13 +0200 Subject: [PATCH] printk: convert byte-buffer to variable-length record buffer The symptom is that the kernel loads and hangs during early boot without displaying anything. My config had CONFIG_EARLY_PRINTK enabled so I tried without it again just in case it would be related, but it desperately did not change anything, the kernel still fails to boot. I have tried to revert printk changes on top of 3.5-rc3 and confirm that now the kernel properly boots. Here's the list of what I reverted for information : c313af145b9bc4fb8e8e0c83b8cfc10e1b894a50 printk() - isolate KERN_CONT users from ordinary complete lines 3ce9a7c0ac28561567fadedf1a99272e4970f740 printk() - restore prefix/timestamp printing for multi-newline str 1fce677971e29ceaa7c569741fa9c685a7b1052a printk: add stub for prepend_timestamp() f8450fca6ecdea38b5a882fdf6cd097e3ec8651c printk: correctly align __log_buf 649e6ee33f73ba1c4f2492c6de9aff2254b540cb printk() - restore timestamp printing at console output 5c5d5ca51abd728c8de3be43ffd6bb00f977bfcd printk() - do not merge continuation lines of different threads 7f3a781d6fd81e397c3928c9af33f1fc63232db6 printk - fix compilation for CONFIG_PRINTK=n 5fc3249068c1ed87c6fd485f42ced24132405629 kmsg: use do_div() to divide 64bit integer c4e00daaa96d3a0786f1f4fe6456281c60ef9a16 driver-core: extend dev_printk() to pass structured data e11fea92e13fb91c50bacca799a6131c81929986 kmsg: export printk records to the /dev/kmsg interface 7ff9554bb578ba02166071d2d487b7fc7d860d62 printk: convert byte-buffer to variable-length record buffer I understand that it will be hard to troubleshoot this with that little information :-/ I'm not posting the config not to pollute the list, but have it available if needed. I haven't noticed anything seemingly related on the list, but if you want me to test a patch or to provide more information, feel free to suggest ! I'm still checking if I can spot something. Regards, Willy