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[195.135.220.15]) by mx.google.com with ESMTPS id 46si282853edu.64.2019.04.17.07.41.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 17 Apr 2019 07:41:44 -0700 (PDT) Received-SPF: pass (google.com: domain of mkoutny@suse.com designates 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=pass (google.com: domain of mkoutny@suse.com designates 195.135.220.15 as permitted sender) smtp.mailfrom=mkoutny@suse.com X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id F0045AEEA; Wed, 17 Apr 2019 14:41:43 +0000 (UTC) Date: Wed, 17 Apr 2019 16:41:42 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Michal Hocko Cc: Bartosz Golaszewski , Arun KS , Geert Uytterhoeven , linux-mm@kvack.org, Andrew Morton , Mike Rapoport , Mateusz Guzik , Vlastimil Babka , linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: get_cmdline use arg_lock instead of mmap_sem Message-ID: <20190417144142.GF8962@blackbody.suse.cz> References: <20190417120347.15397-1-mkoutny@suse.com> <20190417134152.GM5878@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190417134152.GM5878@dhcp22.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) 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 Wed, Apr 17, 2019 at 03:41:52PM +0200, Michal Hocko wrote: > Don't we need to use the lock in prctl_set_mm as well then? Correct. The patch alone just moves the race from get_cmdline/prctl_set_mm_map to get_cmdline/prctl_set_mm. arg_lock could be used in prctl_set_mm but the better idea (IMO) is complete removal of that code in favor of prctl_set_mm_map [1]. Michal [1] https://lore.kernel.org/lkml/20180405182651.GM15783@uranus.lan/