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From:   Naresh Kamboju <naresh.kamboju@linaro.org>
Date:   Tue, 25 Jul 2023 12:03:45 +0530
Message-ID: <CA+G9fYvjJgLyEHymByjE8y4OhWfTWbUmQOn0oT2FZoL3T4orVw@mail.gmail.com>
Subject: Re: next: Rpi4: Unexpected kernel BRK exception at EL1
To:     Puranjay Mohan <puranjay12@gmail.com>
Cc:     Mark Rutland <mark.rutland@arm.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>,
        linux-rpi-kernel@lists.infradead.org,
        Netdev <netdev@vger.kernel.org>, lkft-triage@lists.linaro.org,
        Arnd Bergmann <arnd@arndb.de>,
        Dan Carpenter <dan.carpenter@linaro.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Song Liu <song@kernel.org>, Alexei Starovoitov <ast@kernel.org>
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Hi Puranjay,

On Mon, 3 Jul 2023 at 15:07, Puranjay Mohan <puranjay12@gmail.com> wrote:
>
> Hi Naresh,
>
> On Mon, Jun 26, 2023 at 11:04=E2=80=AFAM Puranjay Mohan <puranjay12@gmail=
.com> wrote:
> >
> > Hi Naresh,
> >
> > On Thu, Jun 22, 2023 at 2:35=E2=80=AFPM Naresh Kamboju
> > <naresh.kamboju@linaro.org> wrote:
> > >
> > > Hi Mark,
> > >
> > > On Thu, 22 Jun 2023 at 15:12, Mark Rutland <mark.rutland@arm.com> wro=
te:
> > > >
> > > > On Wed, Jun 21, 2023 at 01:57:21PM +0100, Mark Rutland wrote:
> > > > > On Wed, Jun 21, 2023 at 06:06:51PM +0530, Naresh Kamboju wrote:
> > > > > > Following boot warnings and crashes noticed on arm64 Rpi4 devic=
e running
> > > > > > Linux next-20230621 kernel.
> > > > > >
> > > > > > Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> > > > > >
> > > > > > boot log:
> > > > > >
> > > > > > [   22.331748] Kernel text patching generated an invalid instru=
ction
> > > > > > at 0xffff8000835d6580!
> > > > > > [   22.340579] Unexpected kernel BRK exception at EL1
> > > > > > [   22.346141] Internal error: BRK handler: 00000000f2000100 [#=
1] PREEMPT SMP
> > > > >
> > > > > This indicates execution of AARCH64_BREAK_FAULT.
> > > > >
> > > > > That could be from dodgy arguments to aarch64_insn_gen_*(), or el=
sewhere, and
> > > > > given this is in the networking code I suspect this'll be related=
 to BPF.
> > > > >
> > > > > Looking at next-20230621 I see commit:
> > > > >
> > > > >   49703aa2adfaff28 ("bpf, arm64: use bpf_jit_binary_pack_alloc")
> > > > >
> > > > > ... which changed the way BPF allocates memory, and has code that=
 pads memory
> > > > > with a bunch of AARCH64_BREAK_FAULT, so it looks like that *might=
* be related.
> > > >
> > > > For the benefit of those just looknig at this thread, there has bee=
n some
> > > > discussion in the original thread for this commit. Summary and link=
s below.
> > > >
> > > > We identified a potential issue with missing cache maintenance:
> > > >
> > > >   https://lore.kernel.org/linux-arm-kernel/ZJMXqTffB22LSOkd@FVFF77S=
0Q05N/
> > > >
> > > > Puranjay verified that was causing the problem seen here:
> > > >
> > > >   https://lore.kernel.org/linux-arm-kernel/CANk7y0h5ucxmMz4K8sGx7qo=
gFyx6PRxYxmFtwTRO7=3D0Y=3DB4ugw@mail.gmail.com/
> > > >
> > > > Alexei has dropped this commit for now:
> > > >
> > > >   https://lore.kernel.org/linux-arm-kernel/CAADnVQJqDOMABEx8JuU6r_D=
ehyf=3DSkDfRNChx1oNfqPoo7pSrw@mail.gmail.com/
> > >
> > > Thanks for the detailed information.
> > > I am happy to test any proposed fix patches.
> >
> > I have sent the v4 of the patch series:
> > https://lore.kernel.org/bpf/20230626085811.3192402-1-puranjay12@gmail.c=
om/T/#t
> > This works on my raspberry pi 4 setup. If possible can you test this
> > on the similar setup where it was failing earlier?
>
> I think my previous email was missed.
> Can you test the V4 series in the same setup?

I have tested V4 series and reported issues got fixed.

Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>

Thank you !

> This is still not applied to the bpf-next tree.
>
> Thanks,
> Puranjay.

- Naresh