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,URIBL_BLOCKED,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 65469C433C1 for ; Fri, 26 Mar 2021 11:27:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 07E3461A2D for ; Fri, 26 Mar 2021 11:27:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 07E3461A2D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gentoo.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2C8616B0036; Fri, 26 Mar 2021 07:27:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 277AE6B006E; Fri, 26 Mar 2021 07:27:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 140216B0070; Fri, 26 Mar 2021 07:27:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id ED17B6B0036 for ; Fri, 26 Mar 2021 07:26:59 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 99674181AEF3E for ; Fri, 26 Mar 2021 11:26:59 +0000 (UTC) X-FDA: 77961798558.06.FACA8DA Received: from smtp.gentoo.org (smtp.gentoo.org [140.211.166.183]) by imf13.hostedemail.com (Postfix) with ESMTP id 3CCBFE0011C5 for ; Fri, 26 Mar 2021 11:26:58 +0000 (UTC) Received: by sf.home (Postfix, from userid 1000) id E89FA5A22061; Fri, 26 Mar 2021 11:26:51 +0000 (GMT) From: Sergei Trofimovich To: Andrew Morton , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Sergei Trofimovich Subject: [PATCH] mm: page_alloc: ignore init_on_free=1 for page alloc Date: Fri, 26 Mar 2021 11:26:50 +0000 Message-Id: <20210326112650.307890-1-slyfox@gentoo.org> X-Mailer: git-send-email 2.31.0 MIME-Version: 1.0 X-Stat-Signature: p46zes5f483ccou6xc6pj5yxtfku6fyz X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 3CCBFE0011C5 Received-SPF: none (gentoo.org>: No applicable sender policy available) receiver=imf13; identity=mailfrom; envelope-from=""; helo=smtp.gentoo.org; client-ip=140.211.166.183 X-HE-DKIM-Result: none/none X-HE-Tag: 1616758018-231537 Content-Transfer-Encoding: quoted-printable 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: init_on_free=3D1 does not guarantee that free pages contain only zero byt= es. Some examples: 1. page_poison=3Don takes presedence over init_on_alloc=3D1 / ini_on_free= =3D1 2. free_pages_prepare() always poisons pages: if (want_init_on_free()) kernel_init_free_pages(page, 1 << order); kernel_poison_pages(page, 1 << order I observed use of poisoned pages as the crash on ia64 booted with init_on_free=3D1 init_on_alloc=3D1 (CONFIG_PAGE_POISONING=3Dy config). There pmd page contained 0xaaaaaaaa poison pages and led to early crash. The change drops the assumption that init_on_free=3D1 guarantees free pages to contain zeros. Alternative would be to make interaction between runtime poisoning and sanitizing options and build-time debug flags like CONFIG_PAGE_POISONING more coherent. I took the simpler path. Tested the fix on rx3600. CC: Andrew Morton CC: linux-mm@kvack.org Signed-off-by: Sergei Trofimovich --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cfc72873961d..d57d9b4f7089 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2301,7 +2301,7 @@ inline void post_alloc_hook(struct page *page, unsi= gned int order, kernel_unpoison_pages(page, 1 << order); set_page_owner(page, order, gfp_flags); =20 - if (!want_init_on_free() && want_init_on_alloc(gfp_flags)) + if (want_init_on_alloc(gfp_flags)) kernel_init_free_pages(page, 1 << order); } =20 --=20 2.31.0