Re: syzkaller on risc-v

From: "Björn Töpel" <bjorn.topel@gmail.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>,
	Andreas Schwab <schwab@suse.de>,
	Atish Patra <atish.patra@wdc.com>,
	syzkaller <syzkaller@googlegroups.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Tobias Klauser <tklauser@distanz.ch>,
	linux-riscv <linux-riscv@lists.infradead.org>
Subject: Re: syzkaller on risc-v
Date: Wed, 1 Jul 2020 12:42:12 +0200	[thread overview]
Message-ID: <CAJ+HfNgzyOfr7gXeg+weLf64HHOWmm2Wug5Oc1OrOJN9ZcR5bQ@mail.gmail.com> (raw)
In-Reply-To: <CACT4Y+Y8=0m+Xku_+kQYuiiABgFUDzHBEqUK_FNGs8=f9NGZng@mail.gmail.com>

On Tue, 30 Jun 2020 at 15:27, Dmitry Vyukov <dvyukov@google.com> wrote:
>
> On Tue, Jun 30, 2020 at 3:14 PM Andreas Schwab <schwab@suse.de> wrote:
> >
> > On Jun 30 2020, Dmitry Vyukov wrote:
> >
> > > KASAN would be a prerequisite for testing risc-v on syzbot.
> >
> > You need to implement the GCC support first.
>
> Interesting. Björn claimed KASAN works already.  And there is:
>
> commit 8ad8b72721d0f07fa02dbe71f901743f9c71c8e6
> Author: Nick Hu
> Date:   Mon Jan 6 10:38:32 2020 -0800
>     riscv: Add KASAN support
>
> Is there any known issue with gcc?
> Did anyone try clang? AddressSanitizer pass in clang is
> arch-independent. Not sure about gcc... it looked mostly
> arch-independent.

Weird. Did a quick bisect (just "does it boot with KASAN or not"
test), and this fell out:

--
efca13989250c3edebaf8fcaa8ca7c966739c65a is the first bad commit
commit efca13989250c3edebaf8fcaa8ca7c966739c65a
Author: Atish Patra <atish.patra@wdc.com>
Date:   Tue Mar 17 18:11:37 2020 -0700

    RISC-V: Introduce a new config for SBI v0.1

    We now have SBI v0.2 which is more scalable and extendable to handle
    future needs for RISC-V supervisor interfaces.

    Introduce a new config and move all SBI v0.1 code under that config.
    This allows to implement the new replacement SBI extensions cleanly
    and remove v0.1 extensions easily in future. Currently, the config
    is enabled by default. Once all M-mode software, with v0.1, is no
    longer in use, this config option and all relevant code can be easily
    removed.

    Signed-off-by: Atish Patra <atish.patra@wdc.com>
    Reviewed-by: Anup Patel <anup@brainfault.org>
    Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

 arch/riscv/Kconfig           |   7 +++
 arch/riscv/include/asm/sbi.h |   2 +
 arch/riscv/kernel/sbi.c      | 132 +++++++++++++++++++++++++++++++++++--------
 3 files changed, 118 insertions(+), 23 deletions(-)
--

I'll dig a bit more.

Björn

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