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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 E14FFC04E53 for ; Wed, 15 May 2019 08:38:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id ACC702082E for ; Wed, 15 May 2019 08:38:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ACC702082E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E80736B000A; Wed, 15 May 2019 04:38:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DBA7B6B000C; Wed, 15 May 2019 04:38:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CB25D6B000D; Wed, 15 May 2019 04:38:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-lf1-f71.google.com (mail-lf1-f71.google.com [209.85.167.71]) by kanga.kvack.org (Postfix) with ESMTP id 692BA6B000A for ; Wed, 15 May 2019 04:38:31 -0400 (EDT) Received: by mail-lf1-f71.google.com with SMTP id 17so430176lfr.14 for ; Wed, 15 May 2019 01:38:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:subject:to:cc :references:from:message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=BAqHI2ypPGaioUF0B32f2/XIYx142pgDOlaWD+A8+sw=; b=PfE+Wa1oC78pg5AsGGLSn7cKECxg8VhrPK3snV2h6qPzjexh+haFNA/anL7SsfZ3sZ tUzziu83zoyDguA2GAUfBQQerdx76uL/j1297gHOfr6A0nr77O8F5W0Py9XByWZ1LRGK uJmYZj09N0weQutP2Cvmb9jLjfoUDbMq94Updc4Xp23k1hHED4z+OiIipsk60YVjl7nj k1XLZWPM1ApDFceY6Td/nm10oE6CnHhdvA/c1zsWSxS6/Hb2GFekP8JDLl6mF7tV5Y3x g3b3P0JsYx8gExPi76YOV4NKXUmGLHJhqzw/kYTTxx+oWYQKlesqWku3HFQeBlmNOIkU gmAQ== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of ktkhai@virtuozzo.com designates 185.231.240.75 as permitted sender) smtp.mailfrom=ktkhai@virtuozzo.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=virtuozzo.com X-Gm-Message-State: APjAAAW6GaN2h12yquGIurf1r0VEyMwV28hInwXPLEIwSXahIcq+gx7l Wb6idsjpBMb0qHnp5yLcZ8ixLG7IF8xFWNP2atqI1ZY2GvVTc1amr2jUx82TlwOV4PUUHZxvOyu NZ+sWFSt1lOcZMt0qksgqr2S6ND5kxZ51MGp3LAbD+4XYP9trE+WLfIhY2X8y6Y0QZQ== X-Received: by 2002:a19:6f4d:: with SMTP id n13mr19490817lfk.57.1557909510853; Wed, 15 May 2019 01:38:30 -0700 (PDT) X-Google-Smtp-Source: APXvYqwZpQlO1IFxrZ6s/IHzfQobgS4x6PVRqnFeVidmpt8+RL6d7PH1q6L0LfLE/neYwu8GStw5 X-Received: by 2002:a19:6f4d:: with SMTP id n13mr19490786lfk.57.1557909510095; Wed, 15 May 2019 01:38:30 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1557909510; cv=none; d=google.com; s=arc-20160816; b=pZlBn1nXnpFafyCCeM0san88r0DuNWCUh6h7gCKlc4FymsbWLOIboN4TRzJvvxSzzG CekxOOsHawfodRR3Tf/cdLPLg/JrMv08KVgp7IxTeE5JJX475+dgY5FwyjUaxyczQWhb 3kKCdSV2TP9odeB9zRYQ0AJMsMAaZgUe3+18piGqqNY0SaDQGIb2d0ymTfL27BKARIc+ YZsnx8GzUDYzubm8ZOJEbi1KxU8Qor0RtrWlRgCn2OEoYSAVe0l6JdKj/QQpMMQXhRr6 rF4pOehcvXOG4xYVyag8T43T9+Gnn8l7wfPq+FIu6gSkMEC/oTgSWKLBqLyUD9TVfqWV vDGg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject; bh=BAqHI2ypPGaioUF0B32f2/XIYx142pgDOlaWD+A8+sw=; b=p+xkHJ9/WO8WMwaoyCTKk3nH4vAqj2oxXWnOh+mmPeeaSWmuUtRk84+Ct/oiiWa/Mf OLsZ0LylVc+9bhpBwEwR+O22np0f5rBgGSFeEjHuCz4BSDiVI16KA81/JyeakTDur36M ula45bh6ng1lPWonncqAC2jFC0mBtcB4yJuFZt5hWQA3/Mtca+ZyP+YDEBiIJorISz/1 PNSkejiO8lmwWZEzZv6p+pLY4TIDs3vDbceA/FCDfRbi9M12g0dMBI+5NiBQDkGbTFev +fRIEOI7K7k7NgrO4dTe7FWW1fXiRRmgCovelrdc2ry71hcZqsUE6iZGP6CK9vBvGZGC WwRg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of ktkhai@virtuozzo.com designates 185.231.240.75 as permitted sender) smtp.mailfrom=ktkhai@virtuozzo.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=virtuozzo.com Received: from relay.sw.ru (relay.sw.ru. [185.231.240.75]) by mx.google.com with ESMTPS id h5si1031072ljk.81.2019.05.15.01.38.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 15 May 2019 01:38:30 -0700 (PDT) Received-SPF: pass (google.com: domain of ktkhai@virtuozzo.com designates 185.231.240.75 as permitted sender) client-ip=185.231.240.75; Authentication-Results: mx.google.com; spf=pass (google.com: domain of ktkhai@virtuozzo.com designates 185.231.240.75 as permitted sender) smtp.mailfrom=ktkhai@virtuozzo.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=virtuozzo.com Received: from [172.16.25.169] by relay.sw.ru with esmtp (Exim 4.91) (envelope-from ) id 1hQpQZ-0006hD-8M; Wed, 15 May 2019 11:38:19 +0300 Subject: Re: [PATCH] mm: fix protection of mm_struct fields in get_cmdline() To: Konstantin Khlebnikov , linux-mm@kvack.org, mkoutny@suse.com, Andrew Morton , linux-kernel@vger.kernel.org Cc: Michal Hocko , Yang Shi References: <155790813764.2995.13706842444028749629.stgit@buzz> From: Kirill Tkhai Message-ID: Date: Wed, 15 May 2019 11:38:18 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <155790813764.2995.13706842444028749629.stgit@buzz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US 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: Hi, Konstantin, On 15.05.2019 11:15, Konstantin Khlebnikov wrote: > Since commit 88aa7cc688d4 ("mm: introduce arg_lock to protect arg_start| > end and env_start|end in mm_struct") related mm fields are protected with > separate spinlock and mmap_sem held for read is not enough for protection. > > Fixes: 88aa7cc688d4 ("mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct") > Signed-off-by: Konstantin Khlebnikov is this already fixed in Michal's series: https://lkml.org/lkml/2019/5/2/422 ? Thanks, Kirill > --- > mm/util.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/util.c b/mm/util.c > index e2e4f8c3fa12..540e7c157cf2 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -717,12 +717,12 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) > if (!mm->arg_end) > goto out_mm; /* Shh! No looking before we're done */ > > - down_read(&mm->mmap_sem); > + spin_lock(&mm->arg_lock); > arg_start = mm->arg_start; > arg_end = mm->arg_end; > env_start = mm->env_start; > env_end = mm->env_end; > - up_read(&mm->mmap_sem); > + spin_unlock(&mm->arg_lock); > > len = arg_end - arg_start; > >