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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id j3sm2051048qkk.133.2019.12.03.10.02.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Dec 2019 10:02:51 -0800 (PST) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH RFC v3 18/36] kmsan: disable LOCK_DEBUGGING_SUPPORT Date: Tue, 3 Dec 2019 13:02:50 -0500 Message-Id: References: Cc: Marco Elver , Eric Biggers , Christoph Hellwig , Herbert Xu , Harry Wentland , Vegard Nossum , Dmitry Vyukov , Linux Memory Management List , Al Viro , Andreas Dilger , Andrew Morton , Andrey Konovalov , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , "Darrick J. Wong" , "David S. Miller" , Dmitry Torokhov , Eric Dumazet , Eric Van Hensbergen , Greg Kroah-Hartman , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Marek Szyprowski , Mark Rutland , "Martin K. Petersen" , Martin Schwidefsky , Matthew Wilcox , "Michael S. Tsirkin" , Michal Simek , Petr Mladek , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , Theodore Ts'o , Thomas Gleixner , Vasily Gorbik , Wolfram Sang In-Reply-To: To: Alexander Potapenko X-Mailer: iPhone Mail (17B111) 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 Dec 3, 2019, at 10:14 AM, Alexander Potapenko wrote= : >=20 > Some tools are just not designed to work together. > For example, you won't be able to compile the kernel with both KASAN > and KMSAN enabled at the same time. >=20 > Lockdep doesn't require any instrumentation to work, so it _might_ be > possible to make it work with KMSAN, but it will probably still slow > down the things to an unacceptable level. > I'm inclining towards disabling the two together for now, unless > anyone is willing to address that issue. >=20 > Please let me know if you think I need to keep the link to > https://github.com/google/kmsan/issues/57 in the Kconfig comment, > right now it looks like: >=20 > # KMSAN is currently incompatible with lockdep. Then, I don=E2=80=99t see much value with KMSAN get merged. Although In theo= ry, it does cover a bit more than the existing memory debugging infrastructu= re, but the question is does it worth it? Maybe it needs more data to show a= list of bugs it found that existing debugging options could not find?=