Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752594Ab3CNUje (ORCPT ); Thu, 14 Mar 2013 16:39:34 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35856 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751350Ab3CNUjd (ORCPT ); Thu, 14 Mar 2013 16:39:33 -0400 Date: Thu, 14 Mar 2013 13:39:31 -0700 From: Andrew Morton To: Frederic Weisbecker Cc: Ingo Molnar , LKML , James Hogan , Steven Rostedt , Peter Zijlstra Subject: Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case Message-Id: <20130314133931.3609b75deff58a2df02ca96b@linux-foundation.org> In-Reply-To: <1363271189-6631-3-git-send-email-fweisbec@gmail.com> References: <1363271189-6631-1-git-send-email-fweisbec@gmail.com> <1363271189-6631-3-git-send-email-fweisbec@gmail.com> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2414 Lines: 72 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 ;)) --- 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/