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[209.85.208.176]) by smtp.gmail.com with ESMTPSA id s73sm515055lfe.3.2019.03.07.10.01.28 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Mar 2019 10:01:28 -0800 (PST) Received: by mail-lj1-f176.google.com with SMTP id z25so15070447ljk.8 for ; Thu, 07 Mar 2019 10:01:28 -0800 (PST) X-Received: by 2002:a2e:208a:: with SMTP id g10mr6579542lji.135.1551981269940; Thu, 07 Mar 2019 09:54:29 -0800 (PST) MIME-Version: 1.0 References: <20190307114511.870090179@infradead.org> <20190307115200.697533978@infradead.org> <20190307174135.GJ32477@hirez.programming.kicks-ass.net> In-Reply-To: <20190307174135.GJ32477@hirez.programming.kicks-ass.net> From: Linus Torvalds Date: Thu, 7 Mar 2019 09:54:14 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 18/20] objtool: Add UACCESS validation To: Peter Zijlstra Cc: Thomas Gleixner , Peter Anvin , Julien Thierry , Will Deacon , Andy Lutomirski , Ingo Molnar , Catalin Marinas , James Morse , valentin.schneider@arm.com, Brian Gerst , Josh Poimboeuf , Andrew Lutomirski , Borislav Petkov , Denys Vlasenko , Linux List Kernel Mailing , Dmitry Vyukov , Steven Rostedt Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 7, 2019 at 9:41 AM Peter Zijlstra wrote: > > > > What's the call site that made you go "just add __memset() to the list"? > > __asan_{,un}poinson_stack_memory() > kasan_{,un}poison_shadow() > __memset() Ugh. I think I almost just agree with your decision to just let that memset go unchecked. I'm not saying it's right, but it doesn't seem to be a fight worth fighting. Again, maybe we could avoid the static checking entirely for the complex configs, and just make preempt_schedule() not do it for AC regions. Because AC vs KASAN in general ends up smelling like "not a fight worth fighting" to me. You've done a herculean job, but.. Linus