arm64: unhandled level 0 translation fault

[Will Deacon]

On Tue, Dec 12, 2017 at 05:00:33PM +0100, Geert Uytterhoeven wrote:
> On Tue, Dec 12, 2017 at 4:11 PM, Geert Uytterhoeven
> <geert at linux-m68k.org> wrote:
> > 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).
> 
> v4.15-rc2 is affected, too.

Do you reckon you can bisect between -rc1 and -rc2? We've been unable to
reproduce this on any of our systems, unfortunately.

Will