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[209.85.220.65]) by mx.google.com with SMTPS id w26sor615799lfe.67.2019.04.18.07.09.53 for (Google Transport Security); Thu, 18 Apr 2019 07:09:53 -0700 (PDT) Received-SPF: pass (google.com: domain of gorcunov@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=JyY+dwTc; spf=pass (google.com: domain of gorcunov@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=gorcunov@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=M5siCfHP6BRRv+5HIBdrYDPCmhboYZvbHLTv7FcSa9I=; b=JyY+dwTc08oWjbHxleqxC0ncbbwBF4oMaUwb7ZCNU2WOmjt/quOO1tXrYYzyCyutWC MkvSFQRQoEJiuaxY+6kKHQ2sPvWcr/lTFjEAPqtPCCw6/sdbzvAQtu3yULUJXzxjtibv 8k+Bw0sQElny79mVcnmTijLpGjhiWs5PBh+zGVPdwy55UvoYI8pQh9iz4EHXM7qIkVQ4 BP2CMdn13gGWO3tBbgNChg+k4K5HlKLv9mwaxLirITdao27RB6hCdgcr46bV/al1mi3c OFJDIPBad2L1bYlzkHvi0VOYFEe+orW4Z6SP+qxgZvI6KDeMcCsUYeO+dTau1Y0x0oCx vcfg== X-Google-Smtp-Source: APXvYqzrj4shwzX3in9UPpImegqkTdLb+e4i4bJgo5k2iLRrydA3y8BLZAB2Obk207TGMdal3y75qQ== X-Received: by 2002:a19:f001:: with SMTP id p1mr9821667lfc.27.1555596593484; Thu, 18 Apr 2019 07:09:53 -0700 (PDT) Received: from uranus.localdomain ([5.18.103.226]) by smtp.gmail.com with ESMTPSA id 30sm471858lfr.22.2019.04.18.07.09.52 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 18 Apr 2019 07:09:52 -0700 (PDT) Received: by uranus.localdomain (Postfix, from userid 1000) id 06858460E0B; Thu, 18 Apr 2019 17:09:52 +0300 (MSK) Date: Thu, 18 Apr 2019 17:09:51 +0300 From: Cyrill Gorcunov To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: mhocko@kernel.org, akpm@linux-foundation.org, arunks@codeaurora.org, brgl@bgdev.pl, geert+renesas@glider.be, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mguzik@redhat.com, rppt@linux.ibm.com, vbabka@suse.cz, Laurent Dufour Subject: Re: [PATCH] prctl_set_mm: downgrade mmap_sem to read lock Message-ID: <20190418140951.GH3040@uranus.lan> References: <20190417145548.GN5878@dhcp22.suse.cz> <20190418135039.19987-1-mkoutny@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190418135039.19987-1-mkoutny@suse.com> User-Agent: Mutt/1.11.3 (2019-02-01) 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 Thu, Apr 18, 2019 at 03:50:39PM +0200, Michal Koutný wrote: > I learnt, it's, alas, too late to drop the non PRCTL_SET_MM_MAP calls > [1], so at least downgrade the write acquisition of mmap_sem as in the > patch below (that should be stacked on the previous one or squashed). > > Cyrill, you mentioned lock changes in [1] but the link seems empty. Is > it supposed to be [2]? That could be an alternative to this patch after > some refreshments and clarifications. Yes, seems so. From a glance the patch shold be ok. Michal will review it more carefully today. Thanks!