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Received: from [50.53.2.24] (helo=[192.168.254.17]) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1sws5o-0000000Bb1Z-46SU; Fri, 04 Oct 2024 23:52:17 +0000 Message-ID: <78f05735-cca3-491e-b2d6-c673427efa07@infradead.org> Date: Fri, 4 Oct 2024 16:52:06 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/1] mseal: update mseal.rst To: Jeff Xu Cc: akpm@linux-foundation.org, keescook@chromium.org, corbet@lwn.net, jorgelo@chromium.org, groeck@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, jannh@google.com, sroettger@google.com, pedro.falcato@gmail.com, linux-hardening@vger.kernel.org, willy@infradead.org, gregkh@linuxfoundation.org, torvalds@linux-foundation.org, deraadt@openbsd.org, usama.anjum@collabora.com, surenb@google.com, merimus@google.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, enh@google.com References: <20241001002628.2239032-1-jeffxu@chromium.org> <20241001002628.2239032-2-jeffxu@chromium.org> <4544a4b3-d5b6-4f6b-b3d5-6c309eb8fa9d@infradead.org> Content-Language: en-US From: Randy Dunlap In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 03C3216000B X-Stat-Signature: izrsf5oj7xss3haupyn8m3jogwhxd943 X-HE-Tag: 1728085945-570781 X-HE-Meta: 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 MhPeXq5z W2GY3nitBCh4V13JZ3ZPXHUYJ7upyop+fY1eXFdunTERDM6CWFf1fyRUVwzbUsxr4BGBkt6tPDkrb0K/EA51P181LAbQEqIQcqEOba8mxunChSfHkKxpKX3/jMT7VzOa2hsAQrJfwhRflrK+4FvC0qfRef0/H7XUtCZA8pJBmryE0OeCVXeAS5QVliblZfmovALbduJo88LCn3ErIQtRMS77ZnMM4LjOUwU2dvEbnC8YKYvJ5prolCiHtVtewGMzT7w8NCsnnW+u7/+G9K6l9PwiFUxjlg9quJcHUe0EeUnaNJkP/NVQVo/xdqt5Wp90kXXD7Wyi8cb464X49D2gFNMoTvg== 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: List-Subscribe: List-Unsubscribe: On 10/4/24 9:52 AM, Jeff Xu wrote: >> above is not a sentence but I don't know how to fix it. >> > Would below work ? > > Certain destructive madvise behaviors, specifically MADV_DONTNEED, > MADV_FREE, MADV_DONTNEED_LOCKED, MADV_FREE, MADV_DONTFORK, > MADV_WIPEONFORK, can pose risks when applied to anonymous memory by > threads without write permissions. These behaviors have the potential > to modify region contents by discarding pages, effectively performing > a memset(0) operation on the anonymous memory. Yes, that works. Or at least it explains the problem, like Theo said. Thanks. -- ~Randy