Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753528Ab3CNWet (ORCPT ); Thu, 14 Mar 2013 18:34:49 -0400 Received: from mail-la0-f51.google.com ([209.85.215.51]:48701 "EHLO mail-la0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753233Ab3CNWes (ORCPT ); Thu, 14 Mar 2013 18:34:48 -0400 MIME-Version: 1.0 In-Reply-To: References: <1363271189-6631-1-git-send-email-fweisbec@gmail.com> <1363271189-6631-3-git-send-email-fweisbec@gmail.com> <20130314133931.3609b75deff58a2df02ca96b@linux-foundation.org> Date: Thu, 14 Mar 2013 23:34:46 +0100 Message-ID: Subject: Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case From: Frederic Weisbecker To: Paul Gortmaker Cc: Andrew Morton , Ingo Molnar , LKML , James Hogan , Steven Rostedt , Peter Zijlstra Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2636 Lines: 67 2013/3/14 Paul Gortmaker : > On Thu, Mar 14, 2013 at 4:39 PM, Andrew Morton > wrote: >> On Thu, 14 Mar 2013 15:26:29 +0100 Frederic Weisbecker wrote: >> >>> wake_up_klogd() is useless when CONFIG_PRINTK=n because >>> neither printk() nor printk_sched() are in use and there >>> are actually no waiter on log_wait waitqueue. It should >>> be a stub in this case for users like bust_spinlocks(). >>> >>> Otherwise this results in this warning when CONFIG_PRINTK=n >>> and CONFIG_IRQ_WORK=n: >>> >>> kernel/built-in.o In function `wake_up_klogd': >>> (.text.wake_up_klogd+0xb4): undefined reference to `irq_work_queue' >>> >>> To fix this, provide an off-case for wake_up_klogd() when >>> CONFIG_PRINTK=n. >>> >>> There is much more from console_unlock() and other console >>> related code in printk.c that should be moved under >>> CONFIG_PRINTK. But for now, focus on a minimal fix as we passed >>> the merged window already. >>> >>> --- a/include/linux/kernel.h >>> +++ b/include/linux/kernel.h >>> @@ -390,7 +390,6 @@ extern struct pid *session_of_pgrp(struct pid *pgrp); >>> unsigned long int_sqrt(unsigned long); >>> >>> extern void bust_spinlocks(int yes); >>> -extern void wake_up_klogd(void); >>> extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */ >>> extern int panic_timeout; >>> extern int panic_on_oops; >>> diff --git a/include/linux/printk.h b/include/linux/printk.h >>> index 1249a54..822171f 100644 >>> --- a/include/linux/printk.h >>> +++ b/include/linux/printk.h >>> @@ -134,6 +134,8 @@ extern int printk_delay_msec; >>> extern int dmesg_restrict; >>> extern int kptr_restrict; >>> >>> +extern void wake_up_klogd(void); >>> + >> >> Given this, it would be prudent to include printk.h in >> bust_spinlocks.c. printk.h currently gets included by kernel.h, but >> that doesn't actually seem necessary - nothing in kernel.h calls >> printk(). >> >> (I pity anyone who tries to remove that include from kernel.h ;)) > > Why did you have to say that? Now I'm inclined to poke at it and > just see how bad it really is when I pull on that loose thread... $ git grep "#include " | cut -d: -f1 | uniq | wc -l 29 $ git grep printk | cut -d: -f1 | uniq | wc -l 6689 There is roughly 6689 - 29 = 6660 files to modify :) -- 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/