From nobody Fri Apr 10 20:19:53 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5BBDC25B0E for ; Fri, 19 Aug 2022 08:46:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347738AbiHSIqu (ORCPT ); Fri, 19 Aug 2022 04:46:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58366 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347732AbiHSIqr (ORCPT ); Fri, 19 Aug 2022 04:46:47 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 048F4CAC4D for ; Fri, 19 Aug 2022 01:46:46 -0700 (PDT) Received: from dggpemm500021.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4M8Fck1czWzXdgb; Fri, 19 Aug 2022 16:42:30 +0800 (CST) Received: from dggpemm500013.china.huawei.com (7.185.36.172) by dggpemm500021.china.huawei.com (7.185.36.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 19 Aug 2022 16:46:42 +0800 Received: from ubuntu1804.huawei.com (10.67.175.36) by dggpemm500013.china.huawei.com (7.185.36.172) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 19 Aug 2022 16:46:42 +0800 From: Chen Zhongjin To: CC: , , , , , , , , , Subject: [PATCH v2] x86/unwind/orc: unwind ftrace trampolines with correct orc Date: Fri, 19 Aug 2022 16:43:34 +0800 Message-ID: <20220819084334.244016-1-chenzhongjin@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.67.175.36] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500013.china.huawei.com (7.185.36.172) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When meeting ftrace trampolines in orc unwinding, unwinder uses address of ftrace_{regs_}call address to find the orc, which gets next frame at sp+176. If there is an irq hitting at sub $0xa8,%rsp, the next frame should be sp+8 instead of 176. It makes unwinder skip correct frame and throw warnings such as "wrong direction" or "can't access registers", etc, depending on the content of the wrong frame address. By adding the base address ftrace_{regs_}caller with the offset *ip - ops->trampoline*, we can get the correct address to find orc. Also change "caller" to "tramp_addr" to make variable name conform to its content. Fixes: 6be7fa3c74d1 ("ftrace, orc, x86: Handle ftrace dynamically allocated= trampolines") Cc: Signed-off-by: Chen Zhongjin Reviewed-by: Steven Rostedt (Google) --- v1 -> v2: Add some comments. --- arch/x86/kernel/unwind_orc.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 38185aedf7d1..0ea57da92940 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -93,22 +93,27 @@ static struct orc_entry *orc_find(unsigned long ip); static struct orc_entry *orc_ftrace_find(unsigned long ip) { struct ftrace_ops *ops; - unsigned long caller; + unsigned long tramp_addr, offset; =20 ops =3D ftrace_ops_trampoline(ip); if (!ops) return NULL; =20 + /* Set tramp_addr to the start of the code copied by the trampoline */ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) - caller =3D (unsigned long)ftrace_regs_call; + tramp_addr =3D (unsigned long)ftrace_regs_caller; else - caller =3D (unsigned long)ftrace_call; + tramp_addr =3D (unsigned long)ftrace_caller; + + /* Now place tramp_addr to the location within the trampoline ip is at */ + offset =3D ip - ops->trampoline; + tramp_addr +=3D offset; =20 /* Prevent unlikely recursion */ - if (ip =3D=3D caller) + if (ip =3D=3D tramp_addr) return NULL; =20 - return orc_find(caller); + return orc_find(tramp_addr); } #else static struct orc_entry *orc_ftrace_find(unsigned long ip) --=20 2.17.1