[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240619112332.GL31592@noisy.programming.kicks-ass.net>
Date: Wed, 19 Jun 2024 13:23:32 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Dmitry Vyukov <dvyukov@...gle.com>
Cc: tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
dave.hansen@...ux.intel.com, x86@...nel.org,
linux-kernel@...r.kernel.org, syzkaller@...glegroups.com,
elver@...gle.com, glider@...gle.com, nogikh@...gle.com,
tarasmadan@...gle.com
Subject: Re: [PATCH v2 4/4] x86: Ignore stack unwinding in KCOV
On Tue, Jun 11, 2024 at 09:50:33AM +0200, Dmitry Vyukov wrote:
> Stack unwinding produces large amounts of uninteresting coverage.
> It's called from KASAN kmalloc/kfree hooks, fault injection, etc.
> It's not particularly useful and is not a function of system call args.
> Ignore that code.
This stems from KCOV's purpose being guiding syzkaller as opposed to it
being a more general coverage tool, right?
Is that spelled out anywhere?
Anyway,
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> Signed-off-by: Dmitry Vyukov <dvyukov@...gle.com>
> Reviewed-by: Alexander Potapenko <glider@...gle.com>
> Reviewed-by: Marco Elver <elver@...gle.com>
> Cc: x86@...nel.org
> Cc: linux-kernel@...r.kernel.org
> Cc: syzkaller@...glegroups.com
> ---
> arch/x86/kernel/Makefile | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 20a0dd51700a..cd49ebfae984 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -39,6 +39,14 @@ KMSAN_SANITIZE_sev.o := n
> # first second.
> KCOV_INSTRUMENT_head$(BITS).o := n
> KCOV_INSTRUMENT_sev.o := n
> +# These are called from save_stack_trace() on debug paths,
> +# and produce large amounts of uninteresting coverage.
> +KCOV_INSTRUMENT_stacktrace.o := n
> +KCOV_INSTRUMENT_dumpstack.o := n
> +KCOV_INSTRUMENT_dumpstack_$(BITS).o := n
> +KCOV_INSTRUMENT_unwind_orc.o := n
> +KCOV_INSTRUMENT_unwind_frame.o := n
> +KCOV_INSTRUMENT_unwind_guess.o := n
>
> CFLAGS_irq.o := -I $(src)/../include/asm/trace
>
> --
> 2.45.2.505.gda0bf45e8d-goog
>
Powered by blists - more mailing lists