From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752659AbdFLT3F (ORCPT ); Mon, 12 Jun 2017 15:29:05 -0400 Received: from terminus.zytor.com ([65.50.211.136]:46943 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752469AbdFLT3D (ORCPT ); Mon, 12 Jun 2017 15:29:03 -0400 Date: Mon, 12 Jun 2017 12:25:21 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: michael.thayer@oracle.com, peterz@infradead.org, hpa@zytor.com, hdegoede@redhat.com, frank.mehnert@oracle.com, mingo@kernel.org, torvalds@linux-foundation.org, tglx@linutronix.de, linux-kernel@vger.kernel.org Reply-To: mingo@kernel.org, frank.mehnert@oracle.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, hdegoede@redhat.com, peterz@infradead.org, hpa@zytor.com, michael.thayer@oracle.com In-Reply-To: <20170612180108.w4vgu2ckucmllf3a@hirez.programming.kicks-ass.net> References: <20170612180108.w4vgu2ckucmllf3a@hirez.programming.kicks-ass.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/debug: Handle early WARN_ONs proper Git-Commit-ID: 8a524f803a3e0290cdba6d373361b2cef9752934 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: 8a524f803a3e0290cdba6d373361b2cef9752934 Gitweb: http://git.kernel.org/tip/8a524f803a3e0290cdba6d373361b2cef9752934 Author: Peter Zijlstra AuthorDate: Mon, 12 Jun 2017 13:52:46 +0200 Committer: Thomas Gleixner CommitDate: Mon, 12 Jun 2017 21:17:48 +0200 x86/debug: Handle early WARN_ONs proper Hans managed to trigger a WARN very early in the boot which killed his (Virtual) box. The reason is that the recent rework of WARN() to use UD0 forgot to add the fixup_bug() call to early_fixup_exception(). As a result the kernel does not handle the WARN_ON injected UD0 exception and panics. Add the missing fixup call, so early UD's injected by WARN() get handled. Fixes: 9a93848fe787 ("x86/debug: Implement __WARN() using UD0") Reported-and-tested-by: Hans de Goede Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Frank Mehnert Cc: Hans de Goede Cc: Michael Thayer Link: http://lkml.kernel.org/r/20170612180108.w4vgu2ckucmllf3a@hirez.programming.kicks-ass.net --- arch/x86/include/asm/extable.h | 1 + arch/x86/kernel/traps.c | 2 +- arch/x86/mm/extable.c | 3 +++ 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/extable.h b/arch/x86/include/asm/extable.h index b8ad261..c66d19e 100644 --- a/arch/x86/include/asm/extable.h +++ b/arch/x86/include/asm/extable.h @@ -29,6 +29,7 @@ struct pt_regs; } while (0) extern int fixup_exception(struct pt_regs *regs, int trapnr); +extern int fixup_bug(struct pt_regs *regs, int trapnr); extern bool ex_has_fault_handler(unsigned long ip); extern void early_fixup_exception(struct pt_regs *regs, int trapnr); diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 3995d3a..bf54309 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -182,7 +182,7 @@ int is_valid_bugaddr(unsigned long addr) return ud == INSN_UD0 || ud == INSN_UD2; } -static int fixup_bug(struct pt_regs *regs, int trapnr) +int fixup_bug(struct pt_regs *regs, int trapnr) { if (trapnr != X86_TRAP_UD) return 0; diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 35ea061..0ea8afc 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -162,6 +162,9 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr) if (fixup_exception(regs, trapnr)) return; + if (fixup_bug(regs, trapnr)) + return; + fail: early_printk("PANIC: early exception 0x%02x IP %lx:%lx error %lx cr2 0x%lx\n", (unsigned)trapnr, (unsigned long)regs->cs, regs->ip,