arm64: unhandled level 0 translation fault

[Geert Uytterhoeven]

Hi Will,

On Tue, Dec 12, 2017 at 11:36 AM, Will Deacon <will.deacon at arm.com> wrote:
> On Tue, Dec 12, 2017 at 11:20:09AM +0100, Geert Uytterhoeven wrote:
>> During userspace (Debian jessie NFS root) boot on arm64:
>>
>> rpcbind[1083]: unhandled level 0 translation fault (11) at 0x00000008,
>> esr 0x92000004, in dash[aaaaadf77000+1a000]
>> CPU: 0 PID: 1083 Comm: rpcbind Not tainted
>> 4.15.0-rc3-arm64-renesas-02176-g14f9a1826e48e355 #51
>> Hardware name: Renesas Salvator-X 2nd version board based on r8a7795 ES2.0+ (DT)
>> pstate: 80000000 (Nzcv daif -PAN -UAO)
>> pc : 0xaaaaadf8a51c
>> lr : 0xaaaaadf8ac08
>> sp : 0000ffffcffeac00
>> x29: 0000ffffcffeac00 x28: 0000aaaaadfa1000
>> x27: 0000ffffcffebf7c x26: 0000ffffcffead20
>> x25: 0000aaaacea1c5f0 x24: 0000000000000000
>> x23: 0000aaaaadfa1000 x22: 0000aaaaadfa1000
>> x21: 0000000000000000 x20: 0000000000000008
>> x19: 0000000000000000 x18: 0000ffffcffeb500
>> x17: 0000ffffa22babfc x16: 0000aaaaadfa1ae8
>> x15: 0000ffffa2363588 x14: ffffffffffffffff
>> x13: 0000000000000020 x12: 0000000000000010
>> x11: 0101010101010101 x10: 0000aaaaadfa1000
>> x9 : 00000000ffffff81 x8 : 0000aaaaadfa2000
>> x7 : 0000000000000000 x6 : 0000000000000000
>> x5 : 0000aaaaadfa2338 x4 : 0000aaaaadfa2000
>> x3 : 0000aaaaadfa2338 x2 : 0000000000000000
>> x1 : 0000aaaaadfa28b0 x0 : 0000aaaaadfa4c30
>>
>> Sometimes it happens with other processes, but the main address, esr, and
>> pstate values are always the same.
>>
>> I regularly run arm64/for-next/core (through bi-weekly renesas-drivers
>> releases, so the last time was two weeks ago), but never saw the issue
>> before until today, so probably v4.15-rc1 is OK.
>> Unfortunately it doesn't happen during every boot, which makes it
>> cumbersome to bisect.
>>
>> My first guess was UNMAP_KERNEL_AT_EL0, but even after disabling that,
>> and even without today's arm64/for-next/core merged in, I still managed to
>> reproduce the issue, so I believe it was introduced in v4.15-rc2 or
>> v4.15-rc3.
>
> Urgh, this looks nasty. Thanks for the report! A few questions:
>
>  - Can you share your .config somewhere please?

I managed to reproduce it on plain v4.15-rc3 using both arm64_defconfig, and
renesas_defconfig (from Simon's repo).

>  - What was your last known-good kernel?

v4.15-rc1.

>  - Have you seen it on any other Soc?

I haven't seen it on any Renesas arm32 SoC, only on arm64.

>  - What's the CPU in your SoC?

Quad Cortex A57.

> If I can reproduce the failure here, then I should be able to debug ASAP.

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds