Re: [linus:master] [mm, slub] 0af8489b02: kernel_BUG_at_include/linux/mm.h

From: Oliver Sang
Date: Thu Jan 12 2023 - 02:48:17 EST

hi, Vlastimil,

On Tue, Jan 10, 2023 at 03:09:36PM +0100, Vlastimil Babka wrote:
> On 1/10/23 14:53, Oliver Sang wrote:
> > hi all,
> >
> > On Mon, Jan 09, 2023 at 10:01:15PM +0800, Oliver Sang wrote:
> >>
> >> On Fri, Jan 06, 2023 at 11:13:15AM +0100, Vlastimil Babka wrote:
> >>
> >> > And if the rate at the parent (has it increased thanks to the
> >> > DEBUG_PAGEALLOC?) is sufficient to bisect to the truly first bad commit. Thanks!
> >>
> >> got it. Thanks for suggestion!
> >>
> >> since 0af8489b02 is based on v6.1-rc2, we will test (both rectorture and boot)
> >> with same config upon v6.1-rc2 to see if it's really clean there.
> >> if so we will use dmesg.invalid_opcode:#[##] to trigger new bisect.
> >>
> >> will keep you updated. Thanks
> >
> > by more tests, we cannot make sure the v6.1-rc2 is clean, so we also checked
> > v6.1-rc1 and v6.0. from results, we have low confidence that we can make a
> > successful bisection based on them [1][2]. could you suggest?
>
> So am I reading it right, that the probleam appears to be introduced between
> v6.0 (0 failures) and v6.1-rc1 (>0 failures)? But agree that with such low
> incidence, it's hard to bisect.

yeah, you are reading it right :)

>
> > a further information not sure if it's helpful, [1][2] are both i386 based.
> > we also tried to run boot tests on x86_64 upon commit 0af8489b02, whatever
> > with or without CONFIG_DEBUG_PAGEALLOC/CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT,
> > we never obseve similar issues (also run 999 times).
>
> Yeah it looks very much like something that manifests only on i386 (perhaps
> only in QEMU as well?) and never x86_64.
>
> What might be interesting then is v6.1-rc1 with further modified config to
> enabled CONFIG_SLUB_DEBUG and CONFIG_SLUB_DEBUG_ON. Maybe it will catch the
> culprit sooner. Or maybe it will obscure the bug instead, unfortunately.

oh, seems, unfortunalately, 'obscure' happen :(

we enabled CONFIG_SLUB_DEBUG and CONFIG_SLUB_DEBUG_ON, along with
CONFIG_DEBUG_PAGEALLOC and CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT

boot (we also add the test for v6.2-rc3):
=========================================================================================
compiler/kconfig/rootfs/sleep/tbox_group/testcase:
gcc-11/i386-randconfig-a012-20221226+CONFIG_DEBUG_PAGEALLOC+CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT+CONFIG_SLUB_DEBUG_ON/debian-11.1-i386-20220923.cgz/1/vm-snb/boot

v6.0 v6.1-rc1 v6.1-rc2 56d5a2b9ba85a390473e86b4fe4 0af8489b0216fa1dd83e264bef8 v6.2-rc3
---------------- --------------------------- --------------------------- --------------------------- --------------------------- ---------------------------
fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs
| | | | | | | | | | |
43:999 3% 68:999 4% 84:999 6% 99:999 5% 94:999 4% 86:999 dmesg.invalid_opcode:#[##]
4:999 -0% 2:999 0% 7:999 0% 8:999 0% 4:999 -0% :999 dmesg.kernel_BUG_at_include/linux/mm.h
3:999 0% 4:999 0% 3:999 0% 7:999 0% 5:999 1% 9:999 dmesg.kernel_BUG_at_include/linux/page-flags.h
34:999 3% 61:999 4% 73:999 5% 81:999 5% 85:999 4% 74:999 dmesg.kernel_BUG_at_lib/list_debug.c
:999 0% :999 0% :999 0% 1:999 0% :999 0% :999 dmesg.kernel_BUG_at_mm/internal.h
3:999 -0% 1:999 -0% :999 -0% 2:999 -0% :999 -0% 2:999 dmesg.kernel_BUG_at_mm/page_alloc.c
:999 0% :999 0% 2:999 0% :999 0% :999 0% 2:999 dmesg.kernel_BUG_at_mm/usercopy.c


since now even the v6.0 is not clean, attached one dmesg FYI


below is from rcutorture:
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase/torture_type:
gcc-11/i386-randconfig-a012-20221226+CONFIG_DEBUG_PAGEALLOC+CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT+CONFIG_SLUB_DEBUG_ON/debian-11.1-i386-20220923.cgz/300s/vm-snb/default/rcutorture/tasks-tracing

v6.0 v6.1-rc1 v6.1-rc2 56d5a2b9ba85a390473e86b4fe4 0af8489b0216fa1dd83e264bef8 v6.2-rc3
---------------- --------------------------- --------------------------- --------------------------- --------------------------- ---------------------------
fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs
| | | | | | | | | | |
47:999 3% 72:999 4% 91:999 4% 88:999 3% 76:999 4% 84:999 dmesg.invalid_opcode:#[##]
4:999 0% 8:999 1% 10:999 0% 5:999 0% 4:999 -0% :999 dmesg.kernel_BUG_at_include/linux/mm.h
3:999 -0% 2:999 0% 5:999 0% 5:999 -0% 2:999 1% 8:999 dmesg.kernel_BUG_at_include/linux/page-flags.h
38:999 2% 61:999 4% 75:999 4% 78:999 3% 68:999 4% 73:999 dmesg.kernel_BUG_at_lib/list_debug.c
1:999 0% 1:999 0% 1:999 -0% :999 0% 2:999 0% 2:999 dmesg.kernel_BUG_at_mm/page_alloc.c
1:999 -0% :999 -0% :999 -0% :999 -0% :999 0% 1:999 dmesg.kernel_BUG_at_mm/usercopy.c
>
> Thanks for all your effort!
>
> > [1]
> > boot results:
> > =========================================================================================
> > compiler/kconfig/rootfs/sleep/tbox_group/testcase:
> > gcc-11/i386-randconfig-a012-20221226+CONFIG_DEBUG_PAGEALLOC+CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT/debian-11.1-i386-20220923.cgz/1/vm-snb/boot
> >
> > v6.0 v6.1-rc1 v6.1-rc2 56d5a2b9ba85a390473e86b4fe4 0af8489b0216fa1dd83e264bef8
> > ---------------- --------------------------- --------------------------- --------------------------- ---------------------------
> > fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs
> > | | | | | | | | |
> > :999 0% 2:999 0% 1:999 1% 11:999 21% 208:999 dmesg.invalid_opcode:#[##]
> > :999 0% :999 0% :999 0% 2:999 5% 51:999 dmesg.kernel_BUG_at_include/linux/mm.h
> > :999 0% 1:999 0% :999 0% 4:999 4% 40:999 dmesg.kernel_BUG_at_include/linux/page-flags.h
> > :999 0% 1:999 0% 1:999 0% 4:999 11% 111:999 dmesg.kernel_BUG_at_lib/list_debug.c
> > :999 0% :999 0% :999 0% :999 0% 2:999 dmesg.kernel_BUG_at_mm/page_alloc.c
> > :999 0% :999 0% :999 0% 1:999 0% 3:999 dmesg.kernel_BUG_at_mm/usercopy.c
> >
> > [2]
> > rcutorture results:
> > =========================================================================================
> > compiler/kconfig/rootfs/runtime/tbox_group/test/testcase/torture_type:
> > gcc-11/i386-randconfig-a012-20221226+CONFIG_DEBUG_PAGEALLOC+CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT/debian-11.1-i386-20220923.cgz/300s/vm-snb/default/rcutorture/tasks-tracing
> >
> > v6.0 v6.1-rc1 v6.1-rc2 56d5a2b9ba85a390473e86b4fe4 0af8489b0216fa1dd83e264bef8
> > ---------------- --------------------------- --------------------------- --------------------------- ---------------------------
> > fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs %reproduction fail:runs
> > | | | | | | | | |
> > :999 0% 3:999 0% :999 1% 8:998 20% 200:999 dmesg.invalid_opcode:#[##]
> > :999 0% :999 0% :999 0% :998 5% 51:999 dmesg.kernel_BUG_at_include/linux/mm.h
> > :999 0% :999 0% :999 0% 3:998 4% 42:999 dmesg.kernel_BUG_at_include/linux/page-flags.h
> > :999 0% 3:999 0% :999 0% 4:998 10% 102:999 dmesg.kernel_BUG_at_lib/list_debug.c
> > :999 0% :999 0% :999 0% :998 0% 2:999 dmesg.kernel_BUG_at_mm/page_alloc.c
> > :999 0% :999 0% :999 0% 1:998 0% 3:999 dmesg.kernel_BUG_at_mm/usercopy.c
> >
> >>
> >> >
> >> >
>
>

Attachment: dmesg.xz
Description: application/xz