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Subject: Re: [PATCH] kasan: fix kasan_check_read/write definitions
To:     Arnd Bergmann <arnd@arndb.de>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Anders Roxell <anders.roxell@linaro.org>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Will Deacon <will.deacon@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
References: <20181211133453.2835077-1-arnd@arndb.de>
From:   Andrey Ryabinin <aryabinin@virtuozzo.com>
Message-ID: <478333ec-1866-2908-1111-8b3dda135278@virtuozzo.com>
Date:   Fri, 11 Jan 2019 21:46:50 +0300
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On 12/11/18 4:34 PM, Arnd Bergmann wrote:
> Building little-endian allmodconfig kernels on arm64 started failing
> with the generated atomic.h implementation, since we now try to call
> kasan helpers from the EFI stub:
> 
> aarch64-linux-gnu-ld: drivers/firmware/efi/libstub/arm-stub.stub.o: in function `atomic_set':
> include/generated/atomic-instrumented.h:44: undefined reference to `__efistub_kasan_check_write'
> 
> I suspect that we get similar problems in other files that explicitly
> disable KASAN for some reason but call atomic_t based helper functions.
> 
> We can fix this by checking the predefined __SANITIZE_ADDRESS__ macro
> that the compiler sets instead of checking CONFIG_KASAN, but this in turn
> requires a small hack in mm/kasan/common.c so we do see the extern
> declaration there instead of the inline function.
> 
> Fixes: b1864b828644 ("locking/atomics: build atomic headers as required")
> Reported-by: Anders Roxell <anders.roxell@linaro.org>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---

Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>