From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932332AbaISLsV (ORCPT ); Fri, 19 Sep 2014 07:48:21 -0400 Received: from terminus.zytor.com ([198.137.202.10]:56267 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753558AbaISLsQ (ORCPT ); Fri, 19 Sep 2014 07:48:16 -0400 Date: Fri, 19 Sep 2014 04:46:58 -0700 From: tip-bot for Aaron Tomlin Message-ID: Cc: mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, atomlin@redhat.com, viro@zeniv.linux.org.uk, ddstreet@ieee.org, akpm@linux-foundation.org, ak@linux.intel.com, tglx@linutronix.de, davidlohr@hp.com, lkundrak@v3.sk, linux-kernel@vger.kernel.org, hpa@zytor.com, davem@davemloft.net, paulmck@linux.vnet.ibm.com, keescook@chromium.org, ast@plumgrid.com Reply-To: mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, atomlin@redhat.com, viro@zeniv.linux.org.uk, ddstreet@ieee.org, akpm@linux-foundation.org, ak@linux.intel.com, tglx@linutronix.de, davidlohr@hp.com, lkundrak@v3.sk, linux-kernel@vger.kernel.org, hpa@zytor.com, davem@davemloft.net, paulmck@linux.vnet.ibm.com, keescook@chromium.org, ast@plumgrid.com In-Reply-To: <1410527779-8133-4-git-send-email-atomlin@redhat.com> References: <1410527779-8133-4-git-send-email-atomlin@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched: Add default-disabled option to BUG() when stack end location is overwritten Git-Commit-ID: 0d9e26329b0c9263d4d9e0422d80a0e73268c52f X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 0d9e26329b0c9263d4d9e0422d80a0e73268c52f Gitweb: http://git.kernel.org/tip/0d9e26329b0c9263d4d9e0422d80a0e73268c52f Author: Aaron Tomlin AuthorDate: Fri, 12 Sep 2014 14:16:19 +0100 Committer: Ingo Molnar CommitDate: Fri, 19 Sep 2014 12:35:24 +0200 sched: Add default-disabled option to BUG() when stack end location is overwritten Currently in the event of a stack overrun a call to schedule() does not check for this type of corruption. This corruption is often silent and can go unnoticed. However once the corrupted region is examined at a later stage, the outcome is undefined and often results in a sporadic page fault which cannot be handled. This patch checks for a stack overrun and takes appropriate action since the damage is already done, there is no point in continuing. Signed-off-by: Aaron Tomlin Signed-off-by: Peter Zijlstra (Intel) Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: oleg@redhat.com Cc: riel@redhat.com Cc: prarit@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: mpe@ellerman.id.au Cc: tglx@linutronix.de Cc: rostedt@goodmis.org Cc: hannes@cmpxchg.org Cc: Alexei Starovoitov Cc: Al Viro Cc: Andi Kleen Cc: Andrew Morton Cc: Dan Streetman Cc: Davidlohr Bueso Cc: David S. Miller Cc: Kees Cook Cc: Linus Torvalds Cc: Lubomir Rintel Cc: Paul E. McKenney Link: http://lkml.kernel.org/r/1410527779-8133-4-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 3 +++ lib/Kconfig.debug | 12 ++++++++++++ 2 files changed, 15 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4b1ddeb..61ee2b3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2693,6 +2693,9 @@ 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 /* * Test if we are atomic. Since do_exit() needs to call into * schedule() atomically, we ignore that path. Otherwise whine diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a285900..e58163d 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 n + help + This option checks for a stack overrun on calls to schedule(). + If the stack end location is found to be over written always panic as + the content of the corrupted region can no longer be trusted. + This is to ensure no erroneous behaviour occurs which could result in + data corruption or a sporadic crash at a later stage once the region + is examined. The runtime overhead introduced is minimal. + config TIMER_STATS bool "Collect kernel timers statistics" depends on DEBUG_KERNEL && PROC_FS