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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05A30C433EF for ; Tue, 12 Jul 2022 02:18:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229645AbiGLCSN (ORCPT ); Mon, 11 Jul 2022 22:18:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55584 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229984AbiGLCSA (ORCPT ); Mon, 11 Jul 2022 22:18:00 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 110B72409A; Mon, 11 Jul 2022 19:17:59 -0700 (PDT) Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Lhkqb40zgzhZD8; Tue, 12 Jul 2022 10:15:23 +0800 (CST) Received: from kwepemm600010.china.huawei.com (7.193.23.86) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 12 Jul 2022 10:17:56 +0800 Received: from ubuntu1804.huawei.com (10.67.174.174) by kwepemm600010.china.huawei.com (7.193.23.86) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 12 Jul 2022 10:17:55 +0800 From: Li Huafei To: , , , CC: , , , , , , , , , , , , , , , , , , , , Subject: [PATCH 3/5] ARM: stacktrace: Allow stack trace saving for non-current tasks Date: Tue, 12 Jul 2022 10:15:25 +0800 Message-ID: <20220712021527.109921-4-lihuafei1@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220712021527.109921-1-lihuafei1@huawei.com> References: <20220712021527.109921-1-lihuafei1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.67.174.174] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600010.china.huawei.com (7.193.23.86) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current ARM implementation of save_stack_trace_tsk() does not allow saving stack trace for non-current tasks, which may limit the scenarios in which stack_trace_save_tsk() can be used. Like other architectures, or like ARM's unwind_backtrace(), we can leave it up to the caller to ensure that the task that needs to be unwound is not running. Signed-off-by: Li Huafei --- arch/arm/kernel/stacktrace.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index 3acf51ee46bb..836420c00938 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -171,19 +171,11 @@ static noinline void __save_stack_trace(struct task_struct *tsk, data.no_sched_functions = nosched; if (tsk != current) { -#ifdef CONFIG_SMP - /* - * What guarantees do we have here that 'tsk' is not - * running on another CPU? For now, ignore it as we - * can't guarantee we won't explode. - */ - return; -#else + /* task blocked in __switch_to */ frame.fp = thread_saved_fp(tsk); frame.sp = thread_saved_sp(tsk); frame.lr = 0; /* recovered from the stack */ frame.pc = thread_saved_pc(tsk); -#endif } else { /* We don't want this function nor the caller */ data.skip += 2; -- 2.17.1