Hi Will, On Tue, Dec 12, 2017 at 5:57 PM, Will Deacon <will.deacon@xxxxxxx> wrote: > 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@xxxxxxxxxxxxxx> wrote: >> > On Tue, Dec 12, 2017 at 11:36 AM, Will Deacon <will.deacon@xxxxxxx> 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. I've tried, but ended up on an unrelated XFS merge commit. Probably I marked a few commits good due to not seeing this heisenbug. For reference, here's the bisect log. Bad commits showed one or both of "unhandled level 0 translation fault" and "invalid pointer". Good commits didn't show any during 6 tries. git bisect start # bad: [ae64f9bd1d3621b5e60d7363bc20afb46aede215] Linux 4.15-rc2 git bisect bad ae64f9bd1d3621b5e60d7363bc20afb46aede215 # good: [4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323] Linux 4.15-rc1 git bisect good 4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323 # good: [9e0600f5cf6cecfcab5046d1453a9538c054d8a7] Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm git bisect good 9e0600f5cf6cecfcab5046d1453a9538c054d8a7 # good: [503505bfea19b7d69e2572297e6defa0f9c2404e] Merge branch 'drm-fixes-4.15' of git://people.freedesktop.org/~agd5f/linux into drm-fixes git bisect good 503505bfea19b7d69e2572297e6defa0f9c2404e # good: [ae753ee2771a1bacade56411bb98037b2545c929] Merge tag 'afs-fixes-20171201' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs git bisect good ae753ee2771a1bacade56411bb98037b2545c929 # good: [e1ba1c99dad92c5917b22b1047cf36e4426b124a] Merge tag 'riscv-for-linus-4.15-rc2_cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/linux git bisect good e1ba1c99dad92c5917b22b1047cf36e4426b124a # bad: [2db767d9889cef087149a5eaa35c1497671fa40f] Merge tag 'nfs-for-4.15-2' of git://git.linux-nfs.org/projects/anna/linux-nfs git bisect bad 2db767d9889cef087149a5eaa35c1497671fa40f # good: [22a6c83777ac7c17d6c63891beeeac24cf5da450] xfs: ubsan fixes git bisect good 22a6c83777ac7c17d6c63891beeeac24cf5da450 # bad: [788c1da05b73aee68ed98f05b577c308351f5619] Merge tag 'xfs-4.15-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux git bisect bad 788c1da05b73aee68ed98f05b577c308351f5619 # good: [3b42d385753c22b29d259ccb9d4c3f419e583b30] xfs: scrub inode mode properly git bisect good 3b42d385753c22b29d259ccb9d4c3f419e583b30 # good: [373b0589dc8d58bc09c9a28d03611ae4fb216057] xfs: Properly retry failed dquot items in case of error during buffer writeback git bisect good 373b0589dc8d58bc09c9a28d03611ae4fb216057 # first bad commit: [788c1da05b73aee68ed98f05b577c308351f5619] Merge tag 'xfs-4.15-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux Tomorrow there's another day in bisection paradise... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx 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