From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 035641A0027 for ; Fri, 12 Sep 2014 14:06:59 +1000 (EST) 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 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" Mime-Version: 1.0 Cc: dzickus@redhat.com, jcastillo@redhat.com, riel@redhat.com, prarit@redhat.com, mingo@kernel.com, pzijlstr@redhat.com, peterz@infradead.org, bmr@redhat.com, x86@kernel.org, oleg@redhat.com, rostedt@goodmis.org, linux-kernel@vger.kernel.org, minchan@kernel.org, mingo@redhat.com, tglx@linutronix.de, aneesh.kumar@linux.vnet.ibm.com, hannes@cmpxchg.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, jgh@redhat.com, akpm@google.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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