From nobody Sat Apr 11 07:54:44 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 64705C00140 for ; Mon, 15 Aug 2022 11:01:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241655AbiHOLB1 (ORCPT ); Mon, 15 Aug 2022 07:01:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233539AbiHOLBS (ORCPT ); Mon, 15 Aug 2022 07:01:18 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF5CD23160; Mon, 15 Aug 2022 04:01:15 -0700 (PDT) Received: from dggpemm500020.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4M5rrt59fJzGpJF; Mon, 15 Aug 2022 18:59:42 +0800 (CST) Received: from dggpemm500013.china.huawei.com (7.185.36.172) by dggpemm500020.china.huawei.com (7.185.36.49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 15 Aug 2022 19:01:13 +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; Mon, 15 Aug 2022 19:01:12 +0800 From: Chen Zhongjin To: , , CC: , , , , , , , , , Subject: [PATCH] x86/unwind/orc: Add 'unwind_debug' cmdline option Date: Mon, 15 Aug 2022 18:58:08 +0800 Message-ID: <20220815105808.17385-2-chenzhongjin@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220815105808.17385-1-chenzhongjin@huawei.com> References: <20220815105808.17385-1-chenzhongjin@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.175.36] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) 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" From: Josh Poimboeuf Sometimes the one-line ORC unwinder warnings aren't very helpful. Add a new 'unwind_debug' cmdline option which will dump the full stack contents of the current task when an error condition is encountered. Signed-off-by: Josh Poimboeuf Reviewed-by: Miroslav Benes Reported-by: kernel test robot --- .../admin-guide/kernel-parameters.txt | 6 +++ arch/x86/kernel/unwind_orc.c | 46 +++++++++++++++++++ 2 files changed, 52 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index cc3ea8febc62..85d48f6052fd 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6317,6 +6317,12 @@ unknown_nmi_panic [X86] Cause panic on unknown NMI. =20 + unwind_debug [X86-64] + Enable unwinder debug output. This can be + useful for debugging certain unwinder error + conditions, including corrupt stacks and + bad/missing unwinder metadata. + usbcore.authorized_default=3D [USB] Default USB device authorization: (default -1 =3D authorized except for wireless USB, diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 38185aedf7d1..c539ca39e9f4 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -13,8 +13,13 @@ =20 #define orc_warn_current(args...) \ ({ \ + static bool dumped_before; if (state->task =3D=3D current && !state->error) \ orc_warn(args); \ + if (unwind_debug && !dumped_before) \ + unwind_dump(state); \ + dumped_before =3D true; \ + } \ }) =20 extern int __start_orc_unwind_ip[]; @@ -23,8 +28,49 @@ extern struct orc_entry __start_orc_unwind[]; extern struct orc_entry __stop_orc_unwind[]; =20 static bool orc_init __ro_after_init; +static bool unwind_debug __ro_after_init; static unsigned int lookup_num_blocks __ro_after_init; =20 +static int __init unwind_debug_cmdline(char *str) +{ + unwind_debug =3D true; + + return 0; +} +early_param("unwind_debug", unwind_debug_cmdline); + +static void unwind_dump(struct unwind_state *state) +{ + static bool dumped_before; + unsigned long word, *sp; + struct stack_info stack_info =3D {0}; + unsigned long visit_mask =3D 0; + + if (dumped_before) + return; + + dumped_before =3D true; + + printk_deferred("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\= n", + state->stack_info.type, state->stack_info.next_sp, + state->stack_mask, state->graph_idx); + + for (sp =3D __builtin_frame_address(0); sp; + sp =3D PTR_ALIGN(stack_info.next_sp, sizeof(long))) { + if (get_stack_info(sp, state->task, &stack_info, &visit_mask)) + break; + + for (; sp < stack_info.end; sp++) { + + word =3D READ_ONCE_NOCHECK(*sp); + + printk_deferred("%0*lx: %0*lx (%pB)\n", BITS_PER_LONG/4, + (unsigned long)sp, BITS_PER_LONG/4, + word, (void *)word); + } + } +} + static inline unsigned long orc_ip(const int *ip) { return (unsigned long)ip + *ip;