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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0BE1C433EF for ; Tue, 19 Oct 2021 04:21:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8950B6134F for ; Tue, 19 Oct 2021 04:21:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231604AbhJSEXq (ORCPT ); Tue, 19 Oct 2021 00:23:46 -0400 Received: from foss.arm.com ([217.140.110.172]:44238 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229649AbhJSEXp (ORCPT ); Tue, 19 Oct 2021 00:23:45 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 26C7BD6E; Mon, 18 Oct 2021 21:21:33 -0700 (PDT) Received: from [10.163.74.241] (unknown [10.163.74.241]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E22853F70D; Mon, 18 Oct 2021 21:21:30 -0700 (PDT) Subject: Re: [PATCH] memblock: exclude NOMAP regions from kmemleak To: Mike Rapoport , linux-mm@kvack.org Cc: Andrew Morton , Catalin Marinas , Mike Rapoport , Vladimir Zapolskiy , linux-kernel@vger.kernel.org References: <20211013054756.12177-1-rppt@kernel.org> From: Anshuman Khandual Message-ID: Date: Tue, 19 Oct 2021 09:51:29 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20211013054756.12177-1-rppt@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/13/21 11:17 AM, Mike Rapoport wrote: > From: Mike Rapoport > > Vladimir Zapolskiy reports: > > commit a7259df76702 ("memblock: make memblock_find_in_range method private") > invokes a kernel panic while running kmemleak on OF platforms with nomaped > regions: > > Unable to handle kernel paging request at virtual address fff000021e00000 > [...] > scan_block+0x64/0x170 > scan_gray_list+0xe8/0x17c > kmemleak_scan+0x270/0x514 > kmemleak_write+0x34c/0x4ac > > Indeed, NOMAP regions don't have linear map entries so an attempt to scan > these areas would fault. > > Prevent such faults by excluding NOMAP regions from kmemleak. > > Link: https://lore.kernel.org/all/8ade5174-b143-d621-8c8e-dc6a1898c6fb@linaro.org > Fixes: a7259df76702 ("memblock: make memblock_find_in_range method private") > Signed-off-by: Mike Rapoport > Tested-by: Vladimir Zapolskiy > --- > mm/memblock.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index 184dcd2e5d99..5c3503c98b2f 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -936,7 +936,12 @@ int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size) > */ > int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size) > { > - return memblock_setclr_flag(base, size, 1, MEMBLOCK_NOMAP); > + int ret = memblock_setclr_flag(base, size, 1, MEMBLOCK_NOMAP); > + > + if (!ret) > + kmemleak_free_part_phys(base, size); > + > + return ret; > } > > /** > > base-commit: 64570fbc14f8d7cb3fe3995f20e26bc25ce4b2cc > Reviewed-by: Anshuman Khandual A small nit though. Just wondering. Should not the comment for memblock_mark_nomap() be updated (or add a comment in the function) to explain the reason to call kmemleak_free_part_phys(), to emphasize that a scan would fail for such memory ranges due to lack of linear mapping ?