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Thu, 18 Jan 2024 04:47:07 -0800 (PST) MIME-Version: 1.0 References: <20240118110022.2538350-1-elver@google.com> In-Reply-To: From: Alexander Potapenko Date: Thu, 18 Jan 2024 13:46:26 +0100 Message-ID: Subject: Re: [PATCH] mm, kmsan: fix infinite recursion due to RCU critical section To: Charan Teja Kalla Cc: Marco Elver , Andrew Morton , Dmitry Vyukov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzbot+93a9e8a3dea8d6085e12@syzkaller.appspotmail.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 182E140003 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: xiracxnr1uknq89nkmepy5zkc199oe4s X-HE-Tag: 1705582027-791964 X-HE-Meta: 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 TIQXm+hT NS5m/UZWjUGAGEHK6fM3nKrwMTzS8ip7yQpKc+weKp1QRNmI8MsdypTA2hGBQL+vtvyWC8GyNPM18xAsyxN/bV7PJdrsMm+xdNILcs4EH3ZH8GkXrsJgWh86HMFjSrsNKMlsfQu6q4bttX1iIiaqfDhMuZjXVW2mMX4TrSy5oeZBU2w1e1GijbbvR4xLQbwoh9CXdiW0dAT4Y3xdM0zGLVOzm8QhniR++ue8aRxVK1vYzB8jWI77mibV1uYRY4YFCmhJStsOSwQ+iPyrxQ9nyDaB22hL17HjS8PF7ZmFopXjOqGY3f/wP1M92vv1HpuvCPJe9ownuieh75YTBcSdHHt+KagfhgfZHoHY7lBGma8sjkxYj9S1nkgTvhWB6REyVjLJ8+6wgz9K7t8Zy0WfmU12grg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000014, 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 Thu, Jan 18, 2024 at 12:28=E2=80=AFPM Charan Teja Kalla wrote: > > May I ask if KMSAN also instruments the access to the memory managed as > ZONE_DEVICE. You know this is not the RAM and also these pages will > never be onlined thus also not be available in buddy. Is there a way to tell whether a memory chunk belongs to ZONE_DEVICE by its address? Won't such check involve calling pfn_valid() or a similar function that would also require synchronization? In general, if e.g. one can call memset() on ZONE_DEVICE memory, it is already going to be instrumented by KMSAN.