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([2a02:908:1252:fb60:be8a:bd56:1f94:86e7]) by smtp.gmail.com with ESMTPSA id n12sm12761784ejs.19.2020.11.18.02.57.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Nov 2020 02:57:46 -0800 (PST) Reply-To: christian.koenig@amd.com Subject: Re: [PATCH 1/2] mm: mmap: fix fput in error path v2 To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org References: <20201106114806.46015-1-christian.koenig@amd.com> <20201106114806.46015-2-christian.koenig@amd.com> <20201106144811.cf228ca9278ec78887d42960@linux-foundation.org> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: Date: Wed, 18 Nov 2020 11:57:44 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201106144811.cf228ca9278ec78887d42960@linux-foundation.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 06.11.20 um 23:48 schrieb Andrew Morton: > On Fri, 6 Nov 2020 12:48:05 +0100 "Christian König" wrote: > >> Patch "495c10cc1c0c CHROMIUM: dma-buf: restore args..." >> adds a workaround for a bug in mmap_region. >> >> As the comment states ->mmap() callback can change >> vma->vm_file and so we might call fput() on the wrong file. >> >> Revert the workaround and proper fix this in mmap_region. >> > Seems correct, best I can tell. Presumably all ->mmap() instances will > correctly fput() to original file* if they're rewriting vma->vm_file. Yes, exactly. Patch #2 provides a helper to make sure that everybody gets the get_file()/fput() correctly while updating vma->vm_file. Can I add your acked-by to the patches and push them upstream through drm-misc-next? Thanks, Christian.