Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754123Ab2EXAh1 (ORCPT ); Wed, 23 May 2012 20:37:27 -0400 Received: from mga03.intel.com ([143.182.124.21]:16915 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751399Ab2EXAh0 (ORCPT ); Wed, 23 May 2012 20:37:26 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="147030602" Message-ID: <1337819893.14538.203.camel@ymzhang.sh.intel.com> Subject: Re: [PATCH] printk: ignore recursion_bug flag when MCE in progress From: Yanmin Zhang To: Borislav Petkov Cc: ShuoX Liu , "linux-kernel@vger.kernel.org" , andi@firstfloor.org, Andrew Morton , Tony Luck Date: Thu, 24 May 2012 08:38:13 +0800 In-Reply-To: <20120523100138.GA13506@x1.osrc.amd.com> References: <4FBC444A.6060500@intel.com> <20120523100138.GA13506@x1.osrc.amd.com> Organization: MCG Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.2- Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3576 Lines: 93 On Wed, 2012-05-23 at 12:01 +0200, Borislav Petkov wrote: > + Tony > > On Wed, May 23, 2012 at 09:58:34AM +0800, ShuoX Liu wrote: > > From: ShuoX Liu > > > > When MCE happens in printk, we ignore recursion_bug to make sure > > some MCE logs printed out. Re-use mce_entry variable. > > > > Signed-off-by: Yanmin Zhang > > Signed-off-by: ShuoX Liu > > --- > > I found mce_entry was introduced by commit 553f265f, but it's not > > used now. Why not removed? > > --- > > arch/x86/include/asm/mce.h | 2 -- > > arch/x86/kernel/cpu/mcheck/mce.c | 2 -- > > include/linux/kernel.h | 1 + > > kernel/printk.c | 4 +++- > > 4 files changed, 4 insertions(+), 5 deletions(-) > > > > diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h > > index 441520e..aeda4cc 100644 > > --- a/arch/x86/include/asm/mce.h > > +++ b/arch/x86/include/asm/mce.h > > @@ -187,8 +187,6 @@ int mce_available(struct cpuinfo_x86 *c); > > DECLARE_PER_CPU(unsigned, mce_exception_count); > > DECLARE_PER_CPU(unsigned, mce_poll_count); > > > > -extern atomic_t mce_entry; > > - > > typedef DECLARE_BITMAP(mce_banks_t, MAX_NR_BANKS); > > DECLARE_PER_CPU(mce_banks_t, mce_poll_banks); > > > > diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c > > index 11c9166..6073354 100644 > > --- a/arch/x86/kernel/cpu/mcheck/mce.c > > +++ b/arch/x86/kernel/cpu/mcheck/mce.c > > @@ -61,8 +61,6 @@ int mce_disabled __read_mostly; > > > > #define SPINUNIT 100 /* 100ns */ > > > > -atomic_t mce_entry; > > - > > DEFINE_PER_CPU(unsigned, mce_exception_count); > > > > /* > > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > > index 645231c..24af685 100644 > > --- a/include/linux/kernel.h > > +++ b/include/linux/kernel.h > > @@ -354,6 +354,7 @@ 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 atomic_t mce_entry; > > extern int panic_timeout; > > extern int panic_on_oops; > > extern int panic_on_unrecovered_nmi; > > diff --git a/kernel/printk.c b/kernel/printk.c > > index 473afdb..2bae087 100644 > > --- a/kernel/printk.c > > +++ b/kernel/printk.c > > @@ -79,6 +79,7 @@ int console_printk[4] = { > > int oops_in_progress; > > EXPORT_SYMBOL(oops_in_progress); > > > > +atomic_t mce_entry; > > /* > > * console_sem protects the console_drivers list, and also > > * provides serialisation for access to the entire console > > @@ -864,7 +865,8 @@ asmlinkage int vprintk(const char *fmt, va_list args) > > * recursion and return - but flag the recursion so that > > * it can be printed at the next appropriate moment: > > */ > > - if (!oops_in_progress && !lockdep_recursing(current)) { > > + if (!oops_in_progress && !atomic_read(&mce_entry) > > This is leaking x86-specific (MCE) stuff in generic kernel code. I think > it would be more appropriate to add a in_hw_error() helper or similar > and define it on each arch. I can very well imagine other architectures > would like to print hw error info too... Good idea. We would do so to make it more generic. Thanks, Yanmin -- 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/