From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751917AbbFNMdm (ORCPT ); Sun, 14 Jun 2015 08:33:42 -0400 Received: from mail-wg0-f41.google.com ([74.125.82.41]:33637 "EHLO mail-wg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751185AbbFNMdg (ORCPT ); Sun, 14 Jun 2015 08:33:36 -0400 Date: Sun, 14 Jun 2015 14:33:32 +0200 From: Frederic Weisbecker To: Fengguang Wu Cc: Ingo Molnar , "Peter Zijlstra (Intel)" , LKP , LKML Subject: Re: [sched/preempt] BUG: KASan: out of bounds access in trace_graph_entry at addr ffff88000d717e48 Message-ID: <20150614123331.GA14645@lerouge> References: <20150614085559.GB1911@wfg-t540p.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150614085559.GB1911@wfg-t540p.sh.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jun 14, 2015 at 04:55:59PM +0800, Fengguang Wu wrote: > Hi Frederic, > > FYI, there are a number more bug messages showing up after this commit > > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > commit b30f0e3ffedfa52b1d67a302ae5860c49998e5e2 > Author: Frederic Weisbecker > AuthorDate: Tue May 12 16:41:49 2015 +0200 > Commit: Ingo Molnar > CommitDate: Tue May 19 08:39:12 2015 +0200 > > sched/preempt: Optimize preemption operations on __schedule() callers > > __schedule() disables preemption and some of its callers > (the preempt_schedule*() family) also set PREEMPT_ACTIVE. > > So we have two preempt_count() modifications that could be performed > at once. > > Lets remove the preemption disablement from __schedule() and pull > this responsibility to its callers in order to optimize preempt_count() > operations in a single place. > > Suggested-by: Linus Torvalds > Signed-off-by: Frederic Weisbecker > Signed-off-by: Peter Zijlstra (Intel) > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Link: http://lkml.kernel.org/r/1431441711-29753-5-git-send-email-fweisbec@gmail.com > Signed-off-by: Ingo Molnar Do you still see that issue after latest tip:/sched/core. I fixed it a few days ago with: 9a92e3dc6ad02208a014d0d8404ebbd697e3d5ef (preempt: Reorganize the notrace definitions a bit) 4eaca0a887eaee04fc7a3866d0f5b51b34030dfa (preempt: Use preempt_schedule_context() as the official tracing preemption point) be690035df893385ceaac2323b29be1fb7f2a67f (sched: Make preempt_schedule_context() function-tracing safe) But maybe there are other issues remaining. Thanks.