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From:   John Stultz <jstultz@google.com>
Date:   Thu, 2 Feb 2023 14:48:50 -0800
Message-ID: <CANDhNCpz+vCqXMDES+_cu8PuTi2c9jhcFqZ8TCVJimAOABjCrg@mail.gmail.com>
Subject: Re: [PATCH] arm64: Support Clang UBSAN trap codes for better reporting
To:     Kees Cook <keescook@chromium.org>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.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
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On Thu, Feb 2, 2023 at 2:37 PM Kees Cook <keescook@chromium.org> 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:
>
>   Internal error: BRK handler: 00000000f20003e8 [#1] PREEMPT SMP
>
> After:
>
>   Internal error: UBSAN: shift out of bounds: 00000000f2005514 [#1] PREEMPT SMP
>

This is really great ! When I brought up the opaque error messages
just a few hours ago, I didn't imagine you'd have a solution so
quickly!

I really appreciate your lightning fast effort here!

Really, thanks so much! I think this will have a big impact for folks
running into these new bug catchers.
-john