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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 C05EFC43381 for ; Wed, 17 Mar 2021 14:24:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A8B364F75 for ; Wed, 17 Mar 2021 14:24:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231815AbhCQOXk (ORCPT ); Wed, 17 Mar 2021 10:23:40 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:14078 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231139AbhCQOXR (ORCPT ); Wed, 17 Mar 2021 10:23:17 -0400 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4F0slh052dz17LBs; Wed, 17 Mar 2021 22:21:20 +0800 (CST) Received: from mdc.huawei.com (10.175.112.208) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.498.0; Wed, 17 Mar 2021 22:23:03 +0800 From: Chen Jun To: , CC: , , , Subject: [PATCH 2/2] arm64: stacktrace: Add skip when task == current Date: Wed, 17 Mar 2021 14:20:50 +0000 Message-ID: <20210317142050.57712-3-chenjun102@huawei.com> X-Mailer: git-send-email 2.9.4 In-Reply-To: <20210317142050.57712-1-chenjun102@huawei.com> References: <20210317142050.57712-1-chenjun102@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.112.208] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On ARM64, cat /sys/kernel/debug/page_owner, all pages return the same stack: stack_trace_save+0x4c/0x78 register_early_stack+0x34/0x70 init_page_owner+0x34/0x230 page_ext_init+0x1bc/0x1dc The reason is that: check_recursive_alloc always return 1 because that entries[0] is always equal to ip (__set_page_owner+0x3c/0x60). The root cause is that: commit 5fc57df2f6fd ("arm64: stacktrace: Convert to ARCH_STACKWALK") make the save_trace save 2 more entries. Add skip in arch_stack_walk when task == current. Fixes: 5fc57df2f6fd ("arm64: stacktrace: Convert to ARCH_STACKWALK") Signed-off-by: Chen Jun --- arch/arm64/kernel/stacktrace.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index ad20981..c26b0ac 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -201,11 +201,12 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, if (regs) start_backtrace(&frame, regs->regs[29], regs->pc); - else if (task == current) + else if (task == current) { + ((struct stacktrace_cookie *)cookie)->skip += 2; start_backtrace(&frame, (unsigned long)__builtin_frame_address(0), (unsigned long)arch_stack_walk); - else + } else start_backtrace(&frame, thread_saved_fp(task), thread_saved_pc(task)); -- 2.9.4