Message-ID: <63dd3711.170a0220.c22c8.349c@mx.google.com>
Date:   Fri, 3 Feb 2023 16:32:16 +0000
From:   Kees Cook <keescook@chromium.org>
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        John Stultz <jstultz@google.com>,
        Yongqin Liu <yongqin.liu@linaro.org>,
        Sami Tolvanen <samitolvanen@google.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Yury Norov <yury.norov@gmail.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Marco Elver <elver@google.com>,
        linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Alexander Potapenko <glider@google.com>,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] arm64: Support Clang UBSAN trap codes for better
 reporting
References: <20230202223653.never.473-kees@kernel.org>
 <Y9zawkok2AWy/brZ@FVFF77S0Q05N>
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On Fri, Feb 03, 2023 at 09:58:26AM +0000, Mark Rutland wrote:
> On Thu, Feb 02, 2023 at 10:36:57PM +0000, Kees Cook wrote:
> > On arm64, Clang encodes the UBSAN check type in the esr. Extract this
> > and actually report UBSAN traps with some specificity when building with
> > CONFIG_UBSAN_TRAP. Before:
> 
> Really minor nit, but could we mention CONFIG_UBSAN_TRAP at the start, e.g.
> change that first sentence to:
> 
> | When CONFIG_UBSAN_TRAP=y on arm64, Clang encodes the UBSAN check type into a
> | BRK immediate, which is reported in the ESR.
> 
> I was initially confused since I was aware that there are usually direct
> function calls for the reporting.

Sure, I can rearrange the commit log.

> 
> Other than that, this looks fine to me, and regardless of the above:
> 
> Acked-by: Mark Rutland <mark.rutland@arm.com>

Thanks!

-Kees

-- 
Kees Cook