From: Stephen Rothwell <sfr@canb.auug.org.au>
To: Kees Cook <keescook@chromium.org>
Cc: Dmitry Vyukov <dvyukov@google.com>,
akpm@linux-foundation.org, andreyknvl@google.com,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Marco Elver <elver@google.com>
Subject: Re: [PATCH] kcov: don't instrument with UBSAN
Date: Thu, 10 Dec 2020 08:49:50 +1100 [thread overview]
Message-ID: <20201210084950.208c89ba@canb.auug.org.au> (raw)
In-Reply-To: <202012091054.08D70D4F@keescook>
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Hi all,
On Wed, 9 Dec 2020 10:54:39 -0800 Kees Cook <keescook@chromium.org> wrote:
>
> On Wed, Dec 09, 2020 at 11:01:52AM +0100, Dmitry Vyukov wrote:
> > Both KCOV and UBSAN use compiler instrumentation. If UBSAN detects a bug
> > in KCOV, it may cause infinite recursion via printk and other common
> > functions. We already don't instrument KCOV with KASAN/KCSAN for this
> > reason, don't instrument it with UBSAN as well.
> >
> > As a side effect this also resolves the following gcc warning:
> >
> > conflicting types for built-in function '__sanitizer_cov_trace_switch';
> > expected 'void(long unsigned int, void *)' [-Wbuiltin-declaration-mismatch]
> >
> > It's only reported when kcov.c is compiled with any of the sanitizers
> > enabled. Size of the arguments is correct, it's just that gcc uses 'long'
> > on 64-bit arches and 'long long' on 32-bit arches, while kernel type is
> > always 'long long'.
> >
> > Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> > Suggested-by: Marco Elver <elver@google.com>
> > Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
>
> Thanks for chasing this down!
>
> Andrew, can you add this to the stack of ubsan patches you're carrying,
> please?
Added to linux-next today.
--
Cheers,
Stephen Rothwell
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prev parent reply other threads:[~2020-12-09 21:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 10:01 [PATCH] kcov: don't instrument with UBSAN Dmitry Vyukov
2020-12-09 10:50 ` Marco Elver
2020-12-09 13:51 ` Andrey Konovalov
2020-12-09 18:54 ` Kees Cook
2020-12-09 21:49 ` Stephen Rothwell [this message]
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