From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CD92C54FD0 for ; Thu, 23 Apr 2020 23:15:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBC902077D for ; Thu, 23 Apr 2020 23:15:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729570AbgDWXPr (ORCPT ); Thu, 23 Apr 2020 19:15:47 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:49638 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728398AbgDWXGq (ORCPT ); Thu, 23 Apr 2020 19:06:46 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jRkvT-0004iX-J4; Fri, 24 Apr 2020 00:06:35 +0100 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1jRkvR-00E6p0-3o; Fri, 24 Apr 2020 00:06:33 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Michael Ellerman" , "Christophe Leroy" Date: Fri, 24 Apr 2020 00:05:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 124/245] powerpc/irq: fix stack overflow verification In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.83-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Christophe Leroy commit 099bc4812f09155da77eeb960a983470249c9ce1 upstream. Before commit 0366a1c70b89 ("powerpc/irq: Run softirqs off the top of the irq stack"), check_stack_overflow() was called by do_IRQ(), before switching to the irq stack. In that commit, do_IRQ() was renamed __do_irq(), and is now executing on the irq stack, so check_stack_overflow() has just become almost useless. Move check_stack_overflow() call in do_IRQ() to do the check while still on the current stack. Fixes: 0366a1c70b89 ("powerpc/irq: Run softirqs off the top of the irq stack") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/e033aa8116ab12b7ca9a9c75189ad0741e3b9b5f.1575872340.git.christophe.leroy@c-s.fr Signed-off-by: Ben Hutchings --- arch/powerpc/kernel/irq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -471,8 +471,6 @@ void __do_irq(struct pt_regs *regs) trace_irq_entry(regs); - check_stack_overflow(); - /* * Query the platform PIC for the interrupt & ack it. * @@ -504,6 +502,8 @@ void do_IRQ(struct pt_regs *regs) irqtp = hardirq_ctx[raw_smp_processor_id()]; sirqtp = softirq_ctx[raw_smp_processor_id()]; + check_stack_overflow(); + /* Already there ? */ if (unlikely(curtp == irqtp || curtp == sirqtp)) { __do_irq(regs);