From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753136AbdGXKFL (ORCPT ); Mon, 24 Jul 2017 06:05:11 -0400 Received: from mga03.intel.com ([134.134.136.65]:60472 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752962AbdGXKFE (ORCPT ); Mon, 24 Jul 2017 06:05:04 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,406,1496127600"; d="scan'208";a="290533825" From: Alexander Shishkin To: Thomas Gleixner , Ingo Molnar , Peter Zijlstra Cc: Alexander Shishkin , Arjan van de Ven , Borislav Petkov , Richard Weinberger , Ingo Molnar , linux-kernel@vger.kernel.org Subject: [PATCH] x86/debug: Handle warnings before the notifier chain Date: Mon, 24 Jul 2017 13:04:28 +0300 Message-Id: <20170724100428.19173-1-alexander.shishkin@linux.intel.com> X-Mailer: git-send-email 2.13.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 9a93848fe787 ("x86/debug: Implement __WARN() using UD0") turned warnings into UD0, but the fixup code only runs after the notify_die() chain. This is a problem, in particular, with kgdb, which kicks in as if it was a BUG(). Fix this by running the fixup code before the notifier chain in the invalid op handler path. Signed-off-by: Alexander Shishkin Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Peter Zijlstra Cc: Richard Weinberger Cc: Thomas Gleixner Cc: Ingo Molnar Cc: linux-kernel@vger.kernel.org --- arch/x86/kernel/traps.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index bf54309b85..b2157d4a53 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -221,9 +221,6 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str, if (fixup_exception(regs, trapnr)) return 0; - if (fixup_bug(regs, trapnr)) - return 0; - tsk->thread.error_code = error_code; tsk->thread.trap_nr = trapnr; die(str, regs, error_code); @@ -304,6 +301,13 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str, RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); + /* + * WARN*()s end up here; fix them up before we call the + * notifier chain. + */ + if (!user_mode(regs) && fixup_bug(regs, trapnr)) + return; + if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) != NOTIFY_STOP) { cond_local_irq_enable(regs); -- 2.13.2