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=-11.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 446DAC282DA for ; Wed, 17 Apr 2019 14:23:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1770820872 for ; Wed, 17 Apr 2019 14:23:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="V3kFFrFJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732574AbfDQOXv (ORCPT ); Wed, 17 Apr 2019 10:23:51 -0400 Received: from terminus.zytor.com ([198.137.202.136]:57965 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732299AbfDQOXu (ORCPT ); Wed, 17 Apr 2019 10:23:50 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x3HENZfs3936224 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Wed, 17 Apr 2019 07:23:35 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 terminus.zytor.com x3HENZfs3936224 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2019041743; t=1555511016; bh=lCu953eArxweLjUbgOciGrTaDhPj673WF1FWDJ2Cyuc=; h=Date:From:Cc:Reply-To:In-Reply-To:References:To:Subject:From; b=V3kFFrFJZ2PIaBL6fwIN6j4K+16QECN8Md4gCFgLDO/NVeiRPYxAHMBy4KQTfI/pI 6sdkj8sIz7c4ICr/Wo6hTf74ONFpd6LJtI83i6TdhE1XdAcsnY0J7yWzVjC4wc0DlI yv7k/XLMPWQKnL20Nnu51yD7rRv/Q2EDZ+mWquIHOtwXH82adoUuzh/XU/579onDkU vbh+eK8SpNVCZ2HBCzJ3q72svdJbLyCkmtJW+Ciz8y1C2LqipOJniKX4vo1OmyyNeV YVVQeF1OISA1SQy+wnzkxqpeSm7+yBPuiIppfuG8gB4fIbIRgFfamkCJ2Sis9Qe2qb pOHd4ZgLrXeyg== Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x3HENZBN3936221; Wed, 17 Apr 2019 07:23:35 -0700 Date: Wed, 17 Apr 2019 07:23:35 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Thomas Gleixner Message-ID: Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, luto@kernel.org, bp@suse.de, mingo@redhat.com, sean.j.christopherson@intel.com, jpoimboe@redhat.com, mingo@kernel.org, x86@kernel.org, hpa@zytor.com, nstange@suse.de Reply-To: mingo@redhat.com, bp@suse.de, sean.j.christopherson@intel.com, linux-kernel@vger.kernel.org, luto@kernel.org, tglx@linutronix.de, x86@kernel.org, hpa@zytor.com, nstange@suse.de, jpoimboe@redhat.com, mingo@kernel.org In-Reply-To: <20190414160146.466354762@linutronix.de> References: <20190414160146.466354762@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/irq] x86/irq/64: Remove stack overflow debug code Git-Commit-ID: 117ed45485413b1977bfc638c32bf5b01d53c62b 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 117ed45485413b1977bfc638c32bf5b01d53c62b Gitweb: https://git.kernel.org/tip/117ed45485413b1977bfc638c32bf5b01d53c62b Author: Thomas Gleixner AuthorDate: Sun, 14 Apr 2019 18:00:08 +0200 Committer: Borislav Petkov CommitDate: Wed, 17 Apr 2019 15:41:48 +0200 x86/irq/64: Remove stack overflow debug code All stack types on x86 64-bit have guard pages now. So there is no point in executing probabilistic overflow checks as the guard pages are a accurate and reliable overflow prevention. Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Cc: "H. Peter Anvin" Cc: Andy Lutomirski Cc: Ingo Molnar Cc: Josh Poimboeuf Cc: Nicolai Stange Cc: Sean Christopherson Cc: x86-ml Link: https://lkml.kernel.org/r/20190414160146.466354762@linutronix.de --- arch/x86/Kconfig | 2 +- arch/x86/kernel/irq_64.c | 56 ------------------------------------------------ 2 files changed, 1 insertion(+), 57 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 5ad92419be19..fd06614b09a7 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -14,6 +14,7 @@ config X86_32 select ARCH_WANT_IPC_PARSE_VERSION select CLKSRC_I8253 select CLONE_BACKWARDS + select HAVE_DEBUG_STACKOVERFLOW select MODULES_USE_ELF_REL select OLD_SIGACTION @@ -138,7 +139,6 @@ config X86 select HAVE_COPY_THREAD_TLS select HAVE_C_RECORDMCOUNT select HAVE_DEBUG_KMEMLEAK - select HAVE_DEBUG_STACKOVERFLOW select HAVE_DMA_CONTIGUOUS select HAVE_DYNAMIC_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_REGS diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c index f107eb2021f6..6bf6517a05bb 100644 --- a/arch/x86/kernel/irq_64.c +++ b/arch/x86/kernel/irq_64.c @@ -26,64 +26,8 @@ DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible; DECLARE_INIT_PER_CPU(irq_stack_backing_store); -int sysctl_panic_on_stackoverflow; - -/* - * Probabilistic stack overflow check: - * - * Regular device interrupts can enter on the following stacks: - * - * - User stack - * - * - Kernel task stack - * - * - Interrupt stack if a device driver reenables interrupts - * which should only happen in really old drivers. - * - * - Debug IST stack - * - * All other contexts are invalid. - */ -static inline void stack_overflow_check(struct pt_regs *regs) -{ -#ifdef CONFIG_DEBUG_STACKOVERFLOW -#define STACK_MARGIN 128 - u64 irq_stack_top, irq_stack_bottom, estack_top, estack_bottom; - u64 curbase = (u64)task_stack_page(current); - struct cea_exception_stacks *estacks; - - if (user_mode(regs)) - return; - - if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_MARGIN && - regs->sp <= curbase + THREAD_SIZE) - return; - - irq_stack_top = (u64)__this_cpu_read(hardirq_stack_ptr); - irq_stack_bottom = irq_stack_top - IRQ_STACK_SIZE + STACK_MARGIN; - if (regs->sp >= irq_stack_bottom && regs->sp <= irq_stack_top) - return; - - estacks = __this_cpu_read(cea_exception_stacks); - estack_top = CEA_ESTACK_TOP(estacks, DB); - estack_bottom = CEA_ESTACK_BOT(estacks, DB) + STACK_MARGIN; - if (regs->sp >= estack_bottom && regs->sp <= estack_top) - return; - - WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx, irq stack:%Lx-%Lx, exception stack: %Lx-%Lx, ip:%pF)\n", - current->comm, curbase, regs->sp, - irq_stack_bottom, irq_stack_top, - estack_bottom, estack_top, (void *)regs->ip); - - if (sysctl_panic_on_stackoverflow) - panic("low stack detected by irq handler - check messages\n"); -#endif -} - bool handle_irq(struct irq_desc *desc, struct pt_regs *regs) { - stack_overflow_check(regs); - if (IS_ERR_OR_NULL(desc)) return false;