Re: [PATCH 1/2] m68k: nommu: register start of the memory with memblock

[Greg Ungerer]

Hi Mike,

On 17/6/20 10:33 pm, Greg Ungerer wrote:
> Hi Mike,
>
> On 17/6/20 4:53 pm, Mike Rapoport wrote:
> > From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> >
> > The m68k nommu setup code didn't register the beginning of the physical
> > memory with memblock because it was anyway occupied by the kernel. However,
> > commit fa3354e4ea39 ("mm: free_area_init: use maximal zone PFNs rather than
> > zone sizes") changed zones initialization to use memblock.memory to detect
> > the zone extents and this caused inconsistency between zone PFNs and the
> > actual PFNs:
> >
> > BUG: Bad page state in process swapper pfn:20165
> > page:41fe0ca0 refcount:0 mapcount:1 mapping:00000000 index:0x0 flags: 0x0()
> > raw: 00000000 00000100 00000122 00000000 00000000 00000000 00000000 00000000
> > page dumped because: nonzero mapcount
> > CPU: 0 PID: 1 Comm: swapper Not tainted 5.8.0-rc1-00001-g3a38f8a60c65-dirty #1
> > Stack from 404c9ebc:
> > ÂÂÂÂÂÂÂÂ 404c9ebc 4029ab28 4029ab28 40088470 41fe0ca0 40299e21 40299df1 404ba2a4
> > ÂÂÂÂÂÂÂÂ 00020165 00000000 41fd2c10 402c7ba0 41fd2c04 40088504 41fe0ca0 40299e21
> > ÂÂÂÂÂÂÂÂ 00000000 40088a12 41fe0ca0 41fe0ca4 0000020a 00000000 00000001 402ca000
> > ÂÂÂÂÂÂÂÂ 00000000 41fe0ca0 41fd2c10 41fd2c10 00000000 00000000 402b2388 00000001
> > ÂÂÂÂÂÂÂÂ 400a0934 40091056 404c9f44 404c9f44 40088db4 402c7ba0 00000001 41fd2c04
> > ÂÂÂÂÂÂÂÂ 41fe0ca0 41fd2000 41fe0ca0 40089e02 4026ecf4 40089e4e 41fe0ca0 ffffffff
> > Call Trace:
> > ÂÂÂÂÂÂÂÂ [<40088470>] 0x40088470
> > Â [<40088504>] 0x40088504
> > Â [<40088a12>] 0x40088a12
> > Â [<402ca000>] 0x402ca000
> > Â [<400a0934>] 0x400a0934
> >
> > Adjust the memory registration with memblock to include the beginning of
> > the physical memory and make sure that the area occupied by the kernel is
> > marked as reserved.
> >
> > Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
>
> Acked-by: Greg Ungerer <gerg@xxxxxxxxxxxxxx>

What path do you anticipate this taking into mainline?
I see it is still broken in 5.8-rc3.

Regards
Greg



> > ---
> > Â arch/m68k/kernel/setup_no.c | 3 ++-
> > Â 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/m68k/kernel/setup_no.c b/arch/m68k/kernel/setup_no.c
> > index e779b19e0193..f66f4b1d062e 100644
> > --- a/arch/m68k/kernel/setup_no.c
> > +++ b/arch/m68k/kernel/setup_no.c
> > @@ -138,7 +138,8 @@ void __init setup_arch(char **cmdline_p)
> > ÂÂÂÂÂ pr_debug("MEMORY -> ROMFS=0x%p-0x%06lx MEM=0x%06lx-0x%06lx\n ",
> > ÂÂÂÂÂÂÂÂÂÂ __bss_stop, memory_start, memory_start, memory_end);
> > -ÂÂÂ memblock_add(memory_start, memory_end - memory_start);
> > +ÂÂÂ memblock_add(_rambase, memory_end - _rambase);
> > +ÂÂÂ memblock_reserve(_rambase, memory_start - _rambase);
> > ÂÂÂÂÂ /* Keep a copy of command line */
> > ÂÂÂÂÂ *cmdline_p = &command_line[0];