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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 94422C55178 for ; Sun, 8 Nov 2020 01:16:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A149522210 for ; Sun, 8 Nov 2020 01:16:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=agner.ch header.i=@agner.ch header.b="DsC/Mq/X" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A149522210 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=agner.ch Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F36686B0036; Sat, 7 Nov 2020 20:16:43 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EE66B6B005D; Sat, 7 Nov 2020 20:16:43 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DD5AF6B0068; Sat, 7 Nov 2020 20:16:43 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0151.hostedemail.com [216.40.44.151]) by kanga.kvack.org (Postfix) with ESMTP id ADF346B0036 for ; Sat, 7 Nov 2020 20:16:43 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 4B68B1EE6 for ; Sun, 8 Nov 2020 01:16:43 +0000 (UTC) X-FDA: 77459486286.04.cloth46_3c14fd9272df Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin04.hostedemail.com (Postfix) with ESMTP id 2E0938005A84 for ; Sun, 8 Nov 2020 01:16:43 +0000 (UTC) X-HE-Tag: cloth46_3c14fd9272df X-Filterd-Recvd-Size: 2752 Received: from mail.kmu-office.ch (mail.kmu-office.ch [178.209.48.109]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Sun, 8 Nov 2020 01:16:41 +0000 (UTC) Received: from webmail.kmu-office.ch (unknown [IPv6:2a02:418:6a02::a3]) by mail.kmu-office.ch (Postfix) with ESMTPSA id 44BBE5C0578; Sun, 8 Nov 2020 02:16:38 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=agner.ch; s=dkim; t=1604798198; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dLE43ZLA8hp6UktmPV/LfyXxESj/KMWUrBP1RF1ENVY=; b=DsC/Mq/XXB7fYqz/csDP6ii7P2ZroqESQeOI2mC9ux6+0qR/orbNMOgN1vhjTJA+VtOB9C bFCraFNMPo/XNjKrub1zkWK/TaphtteLuzCx5zQy3p6w16pMDvDWVUIIJrbRiMsDE4s+px ijemFdXgotntVsYjiqoCT0X9Zs6/0D4= MIME-Version: 1.0 Date: Sun, 08 Nov 2020 02:16:37 +0100 From: Stefan Agner To: Andrew Morton Cc: minchan@kernel.org, ngupta@vflare.org, sergey.senozhatsky.work@gmail.com, sjenning@linux.vnet.ibm.com, gregkh@linuxfoundation.org, arnd@arndb.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/zsmalloc: include sparsemem.h for MAX_PHYSMEM_BITS In-Reply-To: <20201107165645.1b139b595b6b64feaca61bcb@linux-foundation.org> References: <20201107165645.1b139b595b6b64feaca61bcb@linux-foundation.org> User-Agent: Roundcube Webmail/1.4.9 Message-ID: X-Sender: stefan@agner.ch Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2020-11-08 01:56, Andrew Morton wrote: > On Sat, 7 Nov 2020 16:22:06 +0100 Stefan Agner wrote: > >> Most architectures define MAX_PHYSMEM_BITS in asm/sparsemem.h and don't >> include it in asm/pgtable.h. Include asm/sparsemem.h directly to get >> the MAX_PHYSMEM_BITS define on all architectures. >> >> This fixes a crash when accessing zram on 32-bit ARM platform with LPAE and >> more than 4GB of memory: >> Unable to handle kernel NULL pointer dereference at virtual address 00000000 > > Mysterious. Presumably without this include, some compilation unit is > picking up the wrong value of MAX_PHYSMEM_BITS? But I couldn't > actually see where/how this occurs. Can you please explain further? Not sure if I got that right, but from what I understand if MAX_PHYSMEM_BITS is not set in mm/zsmalloc.c it will set MAX_PHYSMEM_BITS to BITS_PER_LONG. And this is 32-bit, too short when LPAE is in use... -- Stefan