From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751640AbaILEHB (ORCPT ); Fri, 12 Sep 2014 00:07:01 -0400 Received: from ozlabs.org ([103.22.144.67]:38709 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751109AbaILEHA (ORCPT ); Fri, 12 Sep 2014 00:07:00 -0400 Message-ID: <1410494817.17540.4.camel@concordia> Subject: Re: [PATCH v3 3/3] sched: BUG when stack end location is over written From: Michael Ellerman To: Aaron Tomlin Cc: peterz@infradead.org, dzickus@redhat.com, jcastillo@redhat.com, riel@redhat.com, x86@kernel.org, akpm@linux-foundation.org, minchan@kernel.org, mingo@kernel.com, bmr@redhat.com, prarit@redhat.com, oleg@redhat.com, rostedt@goodmis.org, linux-kernel@vger.kernel.org, hannes@cmpxchg.org, mingo@redhat.com, aneesh.kumar@linux.vnet.ibm.com, akpm@google.com, jgh@redhat.com, linuxppc-dev@lists.ozlabs.org, tglx@linutronix.de, pzijlstr@redhat.com Date: Fri, 12 Sep 2014 14:06:57 +1000 In-Reply-To: <1410450088-18236-4-git-send-email-atomlin@redhat.com> References: <1410255749-2956-1-git-send-email-atomlin@redhat.com> <1410450088-18236-1-git-send-email-atomlin@redhat.com> <1410450088-18236-4-git-send-email-atomlin@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-09-11 at 16:41 +0100, Aaron Tomlin wrote: > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index a285900..2a8280a 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -824,6 +824,18 @@ config SCHEDSTATS > application, you can say N to avoid the very slight overhead > this adds. > > +config SCHED_STACK_END_CHECK > + bool "Detect stack corruption on calls to schedule()" > + depends on DEBUG_KERNEL > + default y Did you really mean default y? Doing so means it will be turned on more or less everywhere, which defeats the purpose of having a config option in the first place. > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index ec1a286..0b70b73 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -2660,6 +2660,9 @@ static noinline void __schedule_bug(struct task_struct *prev) > */ > static inline void schedule_debug(struct task_struct *prev) > { > +#ifdef CONFIG_SCHED_STACK_END_CHECK > + BUG_ON(unlikely(task_stack_end_corrupted(prev))) > +#endif If this was my code I'd make you put that in a static inline. cheers