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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 0FCAFC63777 for ; Fri, 27 Nov 2020 08:41:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B186F22226 for ; Fri, 27 Nov 2020 08:41:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729321AbgK0IlO (ORCPT ); Fri, 27 Nov 2020 03:41:14 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:8418 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728203AbgK0IlN (ORCPT ); Fri, 27 Nov 2020 03:41:13 -0500 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4Cj7PX5XSqz6vHL; Fri, 27 Nov 2020 16:40:48 +0800 (CST) Received: from localhost.localdomain (10.175.112.125) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.487.0; Fri, 27 Nov 2020 16:41:07 +0800 From: Chen Huang To: Paul Walmsley , Palmer Dabbelt , Albert Ou CC: Andrew Morton , , Subject: [PATCH] riscv/stacktrace: fix stackframe without ra on the top Date: Fri, 27 Nov 2020 08:45:02 +0000 Message-ID: <20201127084502.2133722-1-chenhuang5@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.112.125] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a function doesn't have a callee, then it will not push ra into the stack, such as lkdtm_BUG() function: addi sp,sp,-16 sd s0,8(sp) addi s0,sp,16 ebreak Then we use pt_regs as a parameter to walk_stackframe(), for the struct stackframe use {fp,ra} to get information from stack, it will get the wrong value. And the call trace will be: [] lkdtm_BUG+0x6/0x8 ---[ end trace 18da3fbdf08e25d5 ]--- It should be that: [] lkdtm_BUG+0x6/0x8 [] lkdtm_do_action+0x14/0x1c [] direct_entry+0xc0/0x10a [] full_proxy_write+0x42/0x6a [] vfs_write+0x7e/0x214 [] ksys_write+0x98/0xc0 [] sys_write+0xe/0x16 [] ret_from_syscall+0x0/0x2 ---[ end trace 61917f3d9a9fadcd ]--- Signed-off-by: Chen Huang --- arch/riscv/kernel/stacktrace.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index 595342910c3f..d1d4c18335c4 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -57,7 +57,14 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, /* Unwind stack frame */ frame = (struct stackframe *)fp - 1; sp = fp; - fp = frame->fp; + if (regs && (frame->fp & 0x7) && (pc == regs->epc)) { + fp = frame->ra; + pc = regs->ra; + continue; + } else { + fp = frame->fp; + } + pc = ftrace_graph_ret_addr(current, NULL, frame->ra, (unsigned long *)(fp - 8)); } -- 2.17.1