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[79.242.61.139]) by smtp.gmail.com with ESMTPSA id m39sm7731910wms.28.2021.08.12.00.12.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 12 Aug 2021 00:12:54 -0700 (PDT) Subject: Re: mmap denywrite mess (Was: [GIT PULL] overlayfs fixes for 5.14-rc6) To: Linus Torvalds Cc: Miklos Szeredi , =?UTF-8?Q?Christian_K=c3=b6nig?= , Matthew Wilcox , linux-mm , Linux Kernel Mailing List , linux-fsdevel , linux-unionfs@vger.kernel.org References: From: David Hildenbrand Organization: Red Hat Message-ID: Date: Thu, 12 Aug 2021 09:12:53 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11.08.21 18:20, Linus Torvalds wrote: > On Wed, Aug 11, 2021 at 4:45 AM David Hildenbrand wrote: >> >> I proposed a while ago to get rid of VM_DENYWRITE completely: >> >> https://lkml.kernel.org/r/20210423131640.20080-1-david@redhat.com >> >> I haven't looked how much it still applies to current upstream, but >> maybe that might help cleaning up that code. > > I like it. > > I agree that we could - and probably should - just do it this way. > > We don't expose MAP_DENYWRITE to user space any more - and the old > legacy library loading code certainly isn't worth it - and so > effectively the only way to set it is with execve(). > > And yes, it gets rid of all the silly games with the per-mapping flags. I'll rebase, retest and resend, putting you on cc. Then we can discuss if/how/when we might want to go that path. -- Thanks, David / dhildenb