From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id 2EF0C8E0004 for ; Wed, 19 Dec 2018 20:16:56 -0500 (EST) Received: by mail-pf1-f199.google.com with SMTP id 68so114108pfr.6 for ; Wed, 19 Dec 2018 17:16:56 -0800 (PST) Received: from smtprelay.synopsys.com (smtprelay4.synopsys.com. [198.182.47.9]) by mx.google.com with ESMTPS id i20si16799311pgh.187.2018.12.19.17.16.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 19 Dec 2018 17:16:55 -0800 (PST) Subject: Re: [PATCH 1/2] ARC: show_regs: avoid page allocator 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 Message-ID: <49f9edc9-87ee-1efc-58f8-b0d9a52c8a49@synopsys.com> Date: Wed, 19 Dec 2018 17:16:39 -0800 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 Sender: owner-linux-mm@kvack.org List-ID: 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" 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