From: Palmer Dabbelt <palmer@dabbelt.com>
To: tklauser@distanz.ch
Cc: linux-riscv@lists.infradead.org, aou@eecs.berkeley.edu,
dvyukov@google.com, Paul Walmsley <paul.walmsley@sifive.com>
Subject: Re: [PATCH] riscv: Disable KSAN_SANITIZE for vDSO
Date: Thu, 18 Feb 2021 23:15:34 -0800 (PST) [thread overview]
Message-ID: <mhng-f4076110-eb87-47b6-92fb-9170bbf39b7d@palmerdabbelt-glaptop> (raw)
In-Reply-To: <20210216173305.2500-1-tklauser@distanz.ch>
On Tue, 16 Feb 2021 09:33:05 PST (-0800), tklauser@distanz.ch wrote:
> Dmitry Vyukov reports:
>> I've localized one issue with riscv/KASAN:
>> KASAN breaks VDSO and that's I think the root cause of weird faults I
>> saw earlier. The following patch fixes it.
>> Could somebody please upstream this fix? I don't know how to add/run
>> tests for this.
>
> Verified the fix on a kernel with KASAN enabled using vDSO selftests.
>
> Link: https://lore.kernel.org/lkml/CACT4Y+ZNJBnkKHXUf=tm_yuowvZvHwN=0rmJ=7J+xFd+9r_6pQ@mail.gmail.com/
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Tested-by: Tobias Klauser <tklauser@distanz.ch>
> Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
> ---
> arch/riscv/kernel/vdso/Makefile | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
> index 0cfd6da784f8..71a315e73cbe 100644
> --- a/arch/riscv/kernel/vdso/Makefile
> +++ b/arch/riscv/kernel/vdso/Makefile
> @@ -32,9 +32,10 @@ CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
> # Disable -pg to prevent insert call site
> CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
>
> -# Disable gcov profiling for VDSO code
> +# Disable profiling and instrumentation for VDSO code
> GCOV_PROFILE := n
> KCOV_INSTRUMENT := n
> +KASAN_SANITIZE := n
>
> # Force dependency
> $(obj)/vdso.o: $(obj)/vdso.so
This seems reasonable. Building the VDSO with asan results in a bunch of PLT
entries for the VDSO stubs. I don't see a sane way to resolve those, and it
looks like this is what everyone else is doing.
That said, the commit text is a bit funny so I've written one of my own. This
is on for-next, as it's still the merge window. Let me know if the text
doesn't make sense.
Thanks!
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next prev parent reply other threads:[~2021-02-19 7:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-16 17:33 [PATCH] riscv: Disable KSAN_SANITIZE for vDSO Tobias Klauser
2021-02-17 4:36 ` Dmitry Vyukov
2021-02-19 7:15 ` Palmer Dabbelt [this message]
2021-02-19 9:09 ` Tobias Klauser
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