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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 DD876C43387 for ; Thu, 20 Dec 2018 01:16:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DFE920811 for ; Thu, 20 Dec 2018 01:16:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=synopsys.com header.i=@synopsys.com header.b="VP6qLfRp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729287AbeLTBQz (ORCPT ); Wed, 19 Dec 2018 20:16:55 -0500 Received: from smtprelay4.synopsys.com ([198.182.47.9]:58258 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726716AbeLTBQz (ORCPT ); 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Wed, 19 Dec 2018 17:16:53 -0800 Received: from IN01WEHTCB.internal.synopsys.com (10.144.199.105) by IN01WEHTCA.internal.synopsys.com (10.144.199.103) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 20 Dec 2018 06:46:51 +0530 Received: from [10.12.196.32] (10.12.196.32) by IN01WEHTCB.internal.synopsys.com (10.144.199.243) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 20 Dec 2018 06:46:50 +0530 Subject: Re: [PATCH 1/2] ARC: show_regs: avoid page allocator To: Eugeniy Paltsev , "vineet.gupta1@synopsys.com" , "linux-snps-arc@lists.infradead.org" CC: "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , "peterz@infradead.org" , "linux-kernel@vger.kernel.org" Newsgroups: gmane.linux.kernel,gmane.linux.kernel.arc,gmane.linux.kernel.cross-arch,gmane.linux.kernel.mm References: <1545159239-30628-1-git-send-email-vgupta@synopsys.com> <1545159239-30628-2-git-send-email-vgupta@synopsys.com> <1545239047.14089.13.camel@synopsys.com> From: Vineet Gupta Openpgp: preference=signencrypt Autocrypt: addr=vgupta@synopsys.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1545239047.14089.13.camel@synopsys.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.12.196.32] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/19/18 9:04 AM, Eugeniy Paltsev wrote: > As I can see x86 use print_vma_addr() in their show_signal_msg() > function which allocate page with __get_free_page(GFP_NOWAIT); Indeed with that the __get_free_page() lockdep splat is gone. There's a different one now hence my other patch. | [ARCLinux]# ./segv-null-ptr | potentially unexpected fatal signal 11. | BUG: sleeping function called from invalid context at kernel/fork.c:1011 | in_atomic(): 1, irqs_disabled(): 0, pid: 70, name: segv-null-ptr | no locks held by segv-null-ptr/70. | CPU: 0 PID: 70 Comm: segv-null-ptr Not tainted 4.18.0+ #69 | | Stack Trace: | arc_unwind_core+0xcc/0x100 | ___might_sleep+0x17a/0x190 | mmput+0x16/0xb8 | show_regs+0x52/0x310 | get_signal+0x5ee/0x610 | do_signal+0x2c/0x218 | resume_user_mode_begin+0x90/0xd8