From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752858AbbJTJm7 (ORCPT ); Tue, 20 Oct 2015 05:42:59 -0400 Received: from terminus.zytor.com ([198.137.202.10]:50009 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752262AbbJTJmz (ORCPT ); Tue, 20 Oct 2015 05:42:55 -0400 Date: Tue, 20 Oct 2015 02:37:37 -0700 From: tip-bot for Andrey Ryabinin Message-ID: Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, kasan-dev@googlegroups.com, kcc@google.com, akpm@linux-foundation.org, tglx@linutronix.de, andreyknvl@google.com, glider@google.com, aryabinin@virtuozzo.com, paulmck@linux.vnet.ibm.com, dvlasenk@redhat.com, peterz@infradead.org, sasha.levin@oracle.com, mingo@kernel.org, dvyukov@google.com, luto@amacapital.net, hpa@zytor.com, wmglo@dent.med.uni-muenchen.de, bp@alien8.de Reply-To: bp@alien8.de, wmglo@dent.med.uni-muenchen.de, hpa@zytor.com, luto@amacapital.net, dvyukov@google.com, mingo@kernel.org, sasha.levin@oracle.com, dvlasenk@redhat.com, peterz@infradead.org, paulmck@linux.vnet.ibm.com, aryabinin@virtuozzo.com, glider@google.com, andreyknvl@google.com, tglx@linutronix.de, akpm@linux-foundation.org, kcc@google.com, kasan-dev@googlegroups.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org In-Reply-To: <1445243838-17763-3-git-send-email-aryabinin@virtuozzo.com> References: <1445243838-17763-3-git-send-email-aryabinin@virtuozzo.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/mm, kasan: Silence KASAN warnings in get_wchan() Git-Commit-ID: f7d27c35ddff7c100d7a98db499ac0040149ac05 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: f7d27c35ddff7c100d7a98db499ac0040149ac05 Gitweb: http://git.kernel.org/tip/f7d27c35ddff7c100d7a98db499ac0040149ac05 Author: Andrey Ryabinin AuthorDate: Mon, 19 Oct 2015 11:37:18 +0300 Committer: Ingo Molnar CommitDate: Tue, 20 Oct 2015 11:04:19 +0200 x86/mm, kasan: Silence KASAN warnings in get_wchan() get_wchan() is racy by design, it may access volatile stack of running task, thus it may access redzone in a stack frame and cause KASAN to warn about this. Use READ_ONCE_NOCHECK() to silence these warnings. Reported-by: Sasha Levin Signed-off-by: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrew Morton Cc: Andrey Konovalov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: Kostya Serebryany Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Wolfram Gloger Cc: kasan-dev Link: http://lkml.kernel.org/r/1445243838-17763-3-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/process.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 39e585a..e28db18 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -550,14 +550,14 @@ unsigned long get_wchan(struct task_struct *p) if (sp < bottom || sp > top) return 0; - fp = READ_ONCE(*(unsigned long *)sp); + fp = READ_ONCE_NOCHECK(*(unsigned long *)sp); do { if (fp < bottom || fp > top) return 0; - ip = READ_ONCE(*(unsigned long *)(fp + sizeof(unsigned long))); + ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long))); if (!in_sched_functions(ip)) return ip; - fp = READ_ONCE(*(unsigned long *)fp); + fp = READ_ONCE_NOCHECK(*(unsigned long *)fp); } while (count++ < 16 && p->state != TASK_RUNNING); return 0; }