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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 A7F86C5DF60 for ; Thu, 7 Nov 2019 08:19:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7AE4D21D79 for ; Thu, 7 Nov 2019 08:19:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727634AbfKGIT1 (ORCPT ); Thu, 7 Nov 2019 03:19:27 -0500 Received: from mx1.unisoc.com ([222.66.158.135]:16164 "EHLO SHSQR01.unisoc.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726800AbfKGIT1 (ORCPT ); Thu, 7 Nov 2019 03:19:27 -0500 X-Greylist: delayed 1909 seconds by postgrey-1.27 at vger.kernel.org; Thu, 07 Nov 2019 03:19:26 EST Received: from SHSQR01.spreadtrum.com (localhost [127.0.0.2] (may be forged)) by SHSQR01.unisoc.com with ESMTP id xA77lUVu065852 for ; Thu, 7 Nov 2019 15:47:30 +0800 (CST) (envelope-from lvqiang.huang@unisoc.com) Received: from ig2.spreadtrum.com (bjmbx01.spreadtrum.com [10.0.64.7]) by SHSQR01.spreadtrum.com with ESMTPS id xA77j9w1060787 (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO); Thu, 7 Nov 2019 15:45:09 +0800 (CST) (envelope-from lvqiang.huang@unisoc.com) Received: from localhost (10.0.74.59) by BJMBX01.spreadtrum.com (10.0.64.7) with Microsoft SMTP Server (TLS) id 15.0.847.32; Thu, 7 Nov 2019 15:45:14 +0800 From: Lvqiang To: , , , , , , , , , , Subject: [PATCH] ARM: check __ex_table in do_bad() Date: Thu, 7 Nov 2019 15:45:13 +0800 Message-ID: <1573112713-10115-1-git-send-email-Lvqiang.Huang@unisoc.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.0.74.59] X-ClientProxiedBy: shcas04.spreadtrum.com (10.29.35.89) To BJMBX01.spreadtrum.com (10.0.64.7) X-MAIL: SHSQR01.spreadtrum.com xA77j9w1060787 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We got many crashs in for_each_frame+0x18 arch/arm/lib/backtrace.S 1003: ldr r2, [sv_pc, #-4] The backtrace is dump_backtrace show_stack sched_show_task show_state_filter sysrq_handle_showstate_blocked __handle_sysrq write_sysrq_trigger proc_reg_write __vfs_write vfs_write sys_write Related Kernel config CONFIG_CPU_SW_DOMAIN_PAN=y # CONFIG_ARM_UNWIND is not set CONFIG_FRAME_POINTER=y The task A was dumping the stack of an UN task B. However, the task B scheduled to run on another CPU, which cause it stack content changed. Then, task A may hit a page domain fault and die(). [520.661314] Unhandled fault: page domain fault (0x01b) at 0x32848c02 The addr 0x32848c02 is a valid user-space address. PAGE DIRECTORY: d1854000 PGD: d1854ca0 => bb21e835 PMD: d1854ca0 => bb21e835 PTE: bb21e120 => afffa79f With CONFIG_CPU_SW_DOMAIN_PAN=y, a page domain fault occurred. { do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault"}, Without check the __ex_table entry, do_bad() just return fault and die(). .pushsection __ex_table,"a" .long 1003b, 1006b This patch try __ex_table in do_bad(), the same as in __do_kernel_fault(). Signed-off-by: Lvqiang --- arch/arm/mm/fault.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index bd0f482..22f45df 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -487,11 +487,14 @@ static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma) #endif /* CONFIG_ARM_LPAE */ /* - * This abort handler always returns "fault". + * Checks __ex_table before returns "fault". */ static int do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { + if (fixup_exception(regs)) + return 0; + return 1; } -- 1.7.9.5