Re: next/master boot bisection: next-20190215 on beaglebone-black

[Guenter Roeck]

On Thu, Apr 11, 2019 at 1:22 PM Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>
> On Thu, Apr 11, 2019 at 1:08 PM Guenter Roeck <groeck@xxxxxxxxxx> wrote:
> >
> > On Thu, Apr 11, 2019 at 10:35 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > >
> > > On Thu, Apr 11, 2019 at 9:42 AM Guenter Roeck <groeck@xxxxxxxxxx> wrote:
> > > >
> > > > On Thu, Apr 11, 2019 at 9:19 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > > > >
> > > > > On Thu, Mar 7, 2019 at 7:43 AM Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> > > > > > I went ahead and acquired one of these boards to see if I can can
> > > > > > debug this locally.
> > > > >
> > > > > Hi! Any progress on this? Might it be possible to unblock this series
> > > > > for v5.2 by adding a temporary "not on ARM" flag?
> > > > >
> > > >
> > > > Can someone send me a pointer to the series in question ? I would like
> > > > to run it through my testbed.
> > >
> > > It's already in -mm and linux-next (",mm: shuffle initial free memory
> > > to improve memory-side-cache utilization") but it gets enabled with
> > > CONFIG_SHUFFLE_PAGE_ALLOCATOR=y (which was made the default briefly in
> > > -mm which triggered problems on ARM as was reverted).
> > >
> >
> > Boot tests report
> >
> > Qemu test results:
> >     total: 345 pass: 345 fail: 0
> >
> > This is on top of next-20190410 with CONFIG_SHUFFLE_PAGE_ALLOCATOR=y
> > and the known crashes fixed.
>
> In addition to CONFIG_SHUFFLE_PAGE_ALLOCATOR=y you also need the
> kernel command line option "page_alloc.shuffle=1"
>
> ...so I doubt you are running with shuffling enabled. Another way to
> double check is:
>
>    cat /sys/module/page_alloc/parameters/shuffle

Yes, you are right. Because, with it enabled, I see:

Kernel command line: rdinit=/sbin/init page_alloc.shuffle=1 panic=-1
console=ttyAMA0,115200 page_alloc.shuffle=1
------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at ./include/linux/jump_label.h:303
page_alloc_shuffle+0x12c/0x1ac
static_key_enable(): static key 'page_alloc_shuffle_key+0x0/0x4' used
before call to jump_label_init()
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted
5.1.0-rc4-next-20190410-00003-g3367c36ce744 #1
Hardware name: ARM Integrator/CP (Device Tree)
[<c0011c68>] (unwind_backtrace) from [<c000ec48>] (show_stack+0x10/0x18)
[<c000ec48>] (show_stack) from [<c07e9710>] (dump_stack+0x18/0x24)
[<c07e9710>] (dump_stack) from [<c001bb1c>] (__warn+0xe0/0x108)
[<c001bb1c>] (__warn) from [<c001bb88>] (warn_slowpath_fmt+0x44/0x6c)
[<c001bb88>] (warn_slowpath_fmt) from [<c0b0c4a8>]
(page_alloc_shuffle+0x12c/0x1ac)
[<c0b0c4a8>] (page_alloc_shuffle) from [<c0b0c550>] (shuffle_store+0x28/0x48)
[<c0b0c550>] (shuffle_store) from [<c003e6a0>] (parse_args+0x1f4/0x350)
[<c003e6a0>] (parse_args) from [<c0ac3c00>] (start_kernel+0x1c0/0x488)
[<c0ac3c00>] (start_kernel) from [<00000000>] (  (null))

I'll re-run the test, but I suspect it will drown in warnings.

Guenter