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([2a02:8084:e84:2480:228:f8ff:fe6f:83a8]) by smtp.gmail.com with ESMTPSA id d3sm6023321wrp.79.2021.01.22.11.52.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 22 Jan 2021 11:52:58 -0800 (PST) Subject: Re: [PATCH 6/6] mm: Forbid splitting special mappings To: Will Deacon Cc: linux-kernel@vger.kernel.org, Dmitry Safonov <0x7f454c46@gmail.com>, Alexander Viro , Andrew Morton , Andy Lutomirski , Brian Geffon , Catalin Marinas , Dan Williams , Dave Jiang , Hugh Dickins , Ingo Molnar , "Kirill A. Shutemov" , Mike Kravetz , Minchan Kim , Russell King , Thomas Bogendoerfer , Thomas Gleixner , Vishal Verma , Vlastimil Babka , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: <20201013013416.390574-1-dima@arista.com> <20201013013416.390574-7-dima@arista.com> <20210122125858.GC24102@willie-the-truck> <20210122130003.GD24102@willie-the-truck> From: Dmitry Safonov Message-ID: <6afa94d4-40d9-3a34-381d-f14d07338628@arista.com> Date: Fri, 22 Jan 2021 19:52:57 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <20210122130003.GD24102@willie-the-truck> 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: On 1/22/21 1:00 PM, Will Deacon wrote: > On Fri, Jan 22, 2021 at 12:58:58PM +0000, Will Deacon wrote: >> On Tue, Oct 13, 2020 at 02:34:16AM +0100, Dmitry Safonov wrote: >>> Don't allow splitting of vm_special_mapping's. >>> It affects vdso/vvar areas. Uprobes have only one page in xol_area so >>> they aren't affected. >>> >>> Those restrictions were enforced by checks in .mremap() callbacks. >>> Restrict resizing with generic .split() callback. >>> >>> Signed-off-by: Dmitry Safonov >>> --- >>> arch/arm/kernel/vdso.c | 9 --------- >>> arch/arm64/kernel/vdso.c | 41 +++------------------------------------ >>> arch/mips/vdso/genvdso.c | 4 ---- >>> arch/s390/kernel/vdso.c | 11 +---------- >>> arch/x86/entry/vdso/vma.c | 17 ---------------- >>> mm/mmap.c | 12 ++++++++++++ >>> 6 files changed, 16 insertions(+), 78 deletions(-) >> >> For arm64: >> >> Acked-by: Will Deacon > > Wait -- this got merged ages ago! Why am I reading such old email? It's alright, thanks for looking at this again! -- Dmitry