Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753421Ab3CNWYz (ORCPT ); Thu, 14 Mar 2013 18:24:55 -0400 Received: from mail-we0-f177.google.com ([74.125.82.177]:64685 "EHLO mail-we0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753278Ab3CNWYy (ORCPT ); Thu, 14 Mar 2013 18:24:54 -0400 MIME-Version: 1.0 In-Reply-To: <20130314133931.3609b75deff58a2df02ca96b@linux-foundation.org> References: <1363271189-6631-1-git-send-email-fweisbec@gmail.com> <1363271189-6631-3-git-send-email-fweisbec@gmail.com> <20130314133931.3609b75deff58a2df02ca96b@linux-foundation.org> From: Paul Gortmaker Date: Thu, 14 Mar 2013 18:24:22 -0400 X-Google-Sender-Auth: xnL_gtZm5tE9Jb31408hN3vsZAw Message-ID: Subject: Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case To: Andrew Morton Cc: Frederic Weisbecker , 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: 3014 Lines: 86 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... P. -- > > --- a/lib/bust_spinlocks.c~printk-provide-a-wake_up_klogd-off-case-fix > +++ a/lib/bust_spinlocks.c > @@ -8,6 +8,7 @@ > */ > > #include > +#include > #include > #include > #include > @@ -28,5 +29,3 @@ void __attribute__((weak)) bust_spinlock > wake_up_klogd(); > } > } > - > - > _ > > -- > 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/ -- 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/