From patchwork Wed Oct 23 10:27:36 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Hocko X-Patchwork-Id: 11206289 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 65F9C1951 for ; Wed, 23 Oct 2019 10:27:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3CA7C20659 for ; Wed, 23 Oct 2019 10:27:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3CA7C20659 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7B8146B000C; Wed, 23 Oct 2019 06:27:53 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 741006B000D; Wed, 23 Oct 2019 06:27:53 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 62EEB6B000E; Wed, 23 Oct 2019 06:27:53 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0192.hostedemail.com [216.40.44.192]) by kanga.kvack.org (Postfix) with ESMTP id 3E76E6B000C for ; Wed, 23 Oct 2019 06:27:53 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id E85305841 for ; Wed, 23 Oct 2019 10:27:52 +0000 (UTC) X-FDA: 76074673584.15.car83_44c3e8ca28951 X-Spam-Summary: 2,0,0,4a2bc4e052fb1ea7,d41d8cd98f00b204,mstsxfx@gmail.com,:akpm@linux-foundation.org:mgorman@suse.de:longman@redhat.com:hannes@cmpxchg.org:guro@fb.com:vbabka@suse.cz:khlebnikov@yandex-team.ru:jannh@google.com:songliubraving@fb.com:gregkh@linuxfoundation.org:aquini@redhat.com::linux-kernel@vger.kernel.org:mhocko@suse.com,RULES_HIT:41:355:379:541:800:960:966:973:988:989:1260:1311:1314:1345:1359:1437:1515:1534:1541:1711:1730:1747:1777:1792:2196:2199:2393:2559:2562:3138:3139:3140:3141:3142:3352:3865:3867:3868:3871:3872:3874:4321:4385:5007:6119:6120:6261:6742:7576:7903:10004:11026:11473:11658:11914:12043:12296:12297:12517:12519:12555:12679:12895:13069:13221:13229:13311:13357:13894:14096:14181:14384:14721:21067:21080:21444:21451:21627:30045:30054,0,RBL:209.85.128.67:@gmail.com:.lbl8.mailshell.net-62.18.0.100 66.100.201.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:25,LUA_SUMMARY:n one X-HE-Tag: car83_44c3e8ca28951 X-Filterd-Recvd-Size: 4002 Received: from mail-wm1-f67.google.com (mail-wm1-f67.google.com [209.85.128.67]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Wed, 23 Oct 2019 10:27:52 +0000 (UTC) Received: by mail-wm1-f67.google.com with SMTP id g24so11431764wmh.5 for ; Wed, 23 Oct 2019 03:27:52 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=TsLzXYwYLSB8hHF4vHJgIrxG5rx+YZo4hwBqQCis9kU=; b=qtgmDbXy2Y/j79hyRWaEErbIFuI8ba+aUyCox+WyS1kUpdHeGTclhJB+MVppZZP5zS udQLYxJYUAdkNkyXZhEUavjcvz4kShX/G5n0+YuMZ3KFOCYKpgcPx7E86PtNNLqbcC3h BGYFuZlSGhmTi/R9Unoqh81kSdW2wPr0MZr5ZmnuQL0QP3vA+n6/e69uTcOSPQvrwjb4 OWMGeAI4z+LS007HB7MrCQNIKwCvnZza2xbselHX+nbNtOp5MJUaLXwEbOxLUjwaibjo xnA7DCP5UIIZeAItWLVpilaf7oY/ZBFcf+7qXoYFWxTflSTbz8b9SnFXcKi6ddRysO81 VzYw== X-Gm-Message-State: APjAAAVyyeso7cklNPn+mPXKV186/PZYoQiGd4d4Vip2wj1z4xy1rTqW WuAfpQDfIOACub55FvK45Hc= X-Google-Smtp-Source: APXvYqzP6Mht+wSNTC2Mtl2i9OMjpIr9618QNI6FunUy6TCvoivmzg9pmKUkUO33dVax3Omo1X3Haw== X-Received: by 2002:a1c:1d41:: with SMTP id d62mr7091015wmd.32.1571826471365; Wed, 23 Oct 2019 03:27:51 -0700 (PDT) Received: from tiehlicka.suse.cz (ip-37-188-173-3.eurotel.cz. [37.188.173.3]) by smtp.gmail.com with ESMTPSA id u21sm18234122wmu.27.2019.10.23.03.27.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Oct 2019 03:27:50 -0700 (PDT) From: Michal Hocko To: Andrew Morton , Mel Gorman , Waiman Long Cc: Johannes Weiner , Roman Gushchin , Vlastimil Babka , Konstantin Khlebnikov , Jann Horn , Song Liu , Greg Kroah-Hartman , Rafael Aquini , , LKML , Michal Hocko Subject: [RFC PATCH 1/2] mm, vmstat: hide /proc/pagetypeinfo from normal users Date: Wed, 23 Oct 2019 12:27:36 +0200 Message-Id: <20191023102737.32274-2-mhocko@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191023102737.32274-1-mhocko@kernel.org> References: <20191023095607.GE3016@techsingularity.net> <20191023102737.32274-1-mhocko@kernel.org> MIME-Version: 1.0 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: From: Michal Hocko /proc/pagetypeinfo is a debugging tool to examine internal page allocator state wrt to fragmentation. It is not very useful for any other use so normal users really do not need to read this file. Waiman Long has noticed that reading this file can have negative side effects because zone->lock is necessary for gathering data and that a) interferes with the page allocator and its users and b) can lead to hard lockups on large machines which have very long free_list. Reduce both issues by simply not exporting the file to regular users. Reported-by: Waiman Long Cc: stable Signed-off-by: Michal Hocko Acked-by: Mel Gorman Acked-by: Vlastimil Babka Acked-by: Waiman Long Acked-by: Rafael Aquini Acked-by: David Rientjes --- mm/vmstat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmstat.c b/mm/vmstat.c index 6afc892a148a..4e885ecd44d1 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1972,7 +1972,7 @@ void __init init_mm_internals(void) #endif #ifdef CONFIG_PROC_FS proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op); - proc_create_seq("pagetypeinfo", 0444, NULL, &pagetypeinfo_op); + proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op); proc_create_seq("vmstat", 0444, NULL, &vmstat_op); proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op); #endif