Date: Thu, 21 Nov 2019 15:52:52 +0300 From: Andrey Ryabinin <aryabinin@...tuozzo.com> To: Kees Cook <keescook@...omium.org> Cc: Elena Petrova <lenaptr@...gle.com>, Alexander Potapenko <glider@...gle.com>, Dmitry Vyukov <dvyukov@...gle.com>, Linus Torvalds <torvalds@...ux-foundation.org>, Dan Carpenter <dan.carpenter@...cle.com>, "Gustavo A. R. Silva" <gustavo@...eddedor.com>, Arnd Bergmann <arnd@...db.de>, Ard Biesheuvel <ard.biesheuvel@...aro.org>, Andrew Morton <akpm@...ux-foundation.org>, kasan-dev@...glegroups.com, linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com Subject: Re: [PATCH 1/3] ubsan: Add trap instrumentation option On 11/20/19 4:06 AM, Kees Cook wrote: > +config UBSAN_TRAP > + bool "On Sanitizer warnings, stop the offending kernel thread" That description seems inaccurate and confusing. It's not about kernel threads. UBSAN may trigger in any context - kernel thread/user process/interrupts... Probably most of the kernel code runs in the context of user process, so "stop the offending kernel thread" doesn't sound right. > + depends on UBSAN > + depends on $(cc-option, -fsanitize-undefined-trap-on-error) > + help > + Building kernels with Sanitizer features enabled tends to grow > + the kernel size by over 5%, due to adding all the debugging > + text on failure paths. To avoid this, Sanitizer instrumentation > + can just issue a trap. This reduces the kernel size overhead but > + turns all warnings into full thread-killing exceptions. I think we should mention that enabling this option also has a potential to turn some otherwise harmless bugs into more severe problems like lockups, kernel panic etc.. So the people who enable this would better understand what they signing up for.
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