Re: arm32: panic in move_freepages (Was [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid())

[David Hildenbrand]

On 03.05.21 08:26, Mike Rapoport wrote:
> On Fri, Apr 30, 2021 at 07:24:37PM +0800, Kefeng Wang wrote:
> > On 2021/4/30 17:51, Mike Rapoport wrote:
> > > On Thu, Apr 29, 2021 at 06:22:55PM +0800, Kefeng Wang wrote:
> > > > On 2021/4/29 14:57, Mike Rapoport wrote:
> > > >
> > > > > > > Do you use SPARSMEM? If yes, what is your section size?
> > > > > > > What is the value if CONFIG_FORCE_MAX_ZONEORDER in your configuration?
> > > > > > Yes,
> > > > > >
> > > > > > CONFIG_SPARSEMEM=y
> > > > > >
> > > > > > CONFIG_SPARSEMEM_STATIC=y
> > > > > >
> > > > > > CONFIG_FORCE_MAX_ZONEORDER = 11
> > > > > >
> > > > > > CONFIG_PAGE_OFFSET=0xC0000000
> > > > > > CONFIG_HAVE_ARCH_PFN_VALID=y
> > > > > > CONFIG_HIGHMEM=y
> > > > > > #define SECTION_SIZE_BITS    26
> > > > > > #define MAX_PHYSADDR_BITS    32
> > > > > > #define MAX_PHYSMEM_BITS     32
> > > >
> > > >
> > > > With the patch,  the addr is aligned, but the panic still occurred,
> > >
> > > Is this the same panic at move_freepages() for range [de600, de7ff]?
> > >
> > > Do you enable CONFIG_ARM_LPAE?
> >
> > no, the CONFIG_ARM_LPAE is not set, and yes with same panic at
> > move_freepages at
> >
> > start_pfn/end_pfn [de600, de7ff], [de600000, de7ff000] :  pfn =de600, page
> > =ef3cc000, page-flags = ffffffff,  pfn2phy = de600000
> >
> > > > __free_memory_core, range: 0xb0200000 - 0xc0000000, pfn: b0200 - b0200
> > > > __free_memory_core, range: 0xcc000000 - 0xdca00000, pfn: cc000 - b0200
> > > > __free_memory_core, range: 0xde700000 - 0xdea00000, pfn: de700 - b0200
>
> Hmm, [de600, de7ff] is not added to the free lists which is correct. But
> then it's unclear how the page for de600 gets to move_freepages()...
>
> Can't say I have any bright ideas to try here...

Are we missing some checks (e.g., PageReserved()) that 
pfn_valid_within() would have "caught" before?

--
Thanks,

David / dhildenb