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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 C7EBCC4360F for ; Wed, 3 Apr 2019 10:31:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C2C7206DD for ; Wed, 3 Apr 2019 10:31:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726471AbfDCKb0 (ORCPT ); Wed, 3 Apr 2019 06:31:26 -0400 Received: from foss.arm.com ([217.140.101.70]:37004 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726264AbfDCKbZ (ORCPT ); Wed, 3 Apr 2019 06:31:25 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2202E1596; Wed, 3 Apr 2019 03:31:25 -0700 (PDT) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E22443F59C; Wed, 3 Apr 2019 03:31:23 -0700 (PDT) From: Will Deacon To: gregkh@linuxfoundation.org Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org, sashal@kernel.org, Will Deacon , Catalin Marinas Subject: [PATCH 4.4 BACKPORT 2/2] arm64: debug: Ensure debug handlers check triggering exception level Date: Wed, 3 Apr 2019 11:31:14 +0100 Message-Id: <20190403103114.29050-2-will.deacon@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190403103114.29050-1-will.deacon@arm.com> References: <20190403103114.29050-1-will.deacon@arm.com> Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Commit 6bd288569b50bc89fa5513031086746968f585cb upstream. Debug exception handlers may be called for exceptions generated both by user and kernel code. In many cases, this is checked explicitly, but in other cases things either happen to work by happy accident or they go slightly wrong. Fix this issue in the most stable-friendly fashion by simply adding explicit checks of the triggering exception level to all of our debug exception handlers. Cc: # 4.4.y Reviewed-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/kernel/kgdb.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c index bcac81e600b9..f72743dc070d 100644 --- a/arch/arm64/kernel/kgdb.c +++ b/arch/arm64/kernel/kgdb.c @@ -215,22 +215,31 @@ int kgdb_arch_handle_exception(int exception_vector, int signo, static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr) { + if (user_mode(regs)) + return DBG_HOOK_ERROR; + kgdb_handle_exception(1, SIGTRAP, 0, regs); - return 0; + return DBG_HOOK_HANDLED; } static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr) { + if (user_mode(regs)) + return DBG_HOOK_ERROR; + compiled_break = 1; kgdb_handle_exception(1, SIGTRAP, 0, regs); - return 0; + return DBG_HOOK_HANDLED; } static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr) { + if (user_mode(regs)) + return DBG_HOOK_ERROR; + kgdb_handle_exception(1, SIGTRAP, 0, regs); - return 0; + return DBG_HOOK_HANDLED; } static struct break_hook kgdb_brkpt_hook = { -- 2.11.0