On 2021/4/25 15:19, Mike Rapoport wrote:
> On Fri, Apr 23, 2021 at 04:11:16PM +0800, Kefeng Wang wrote:
>> I tested this patchset(plus arm32 change, like arm64 does) based on lts
>> 5.10，add
>>
>> some debug log, the useful info shows below, if we enable HOLES_IN_ZONE, no
>> panic,
>>
>> any idea, thanks.
>   
> Are there any changes on top of 5.10 except for pfn_valid() patch?
> Do you see this panic on 5.10 without the changes?

Yes, there are some BSP support for arm board based on 5.10, with or 
without

your patch will get same panic, the panic pfn=de600 in the range of 
[dcc00,de00]

which is freed by free_memmap, start_pfn = dcc00,  dcc00000 end_pfn = 
de700, de700000

we see the PC is at PageLRU, same reason like arm64 panic log,

"PageBuddy in move_freepages returns false Then we call PageLRU, the 
macro calls PF_HEAD which is compound_page() compound_page reads 
page->compound_head, it is 0xffffffffffffffff, so it resturns 
0xfffffffffffffffe - and accessing this address causes crash"

> Can you see stack backtrace beyond move_freepages_block?

I do some oom test, so the log is about memory allocate,

[<c02383c8>] (move_freepages_block) from [<c0238668>] 
(steal_suitable_fallback+0x174/0x1f4)

[<c0238668>] (steal_suitable_fallback) from [<c023999c>] 
(get_page_from_freelist+0x490/0x9a4)
[<c023999c>] (get_page_from_freelist) from [<c023a4dc>] 
(__alloc_pages_nodemask+0x188/0xc08)
[<c023a4dc>] (__alloc_pages_nodemask) from [<c0223078>] 
(alloc_zeroed_user_highpage_movable+0x14/0x3c)
[<c0223078>] (alloc_zeroed_user_highpage_movable) from [<c0226768>] 
(handle_mm_fault+0x254/0xac8)
[<c0226768>] (handle_mm_fault) from [<c04ba09c>] (do_page_fault+0x228/0x2f4)
[<c04ba09c>] (do_page_fault) from [<c0111d80>] (do_DataAbort+0x48/0xd0)
[<c0111d80>] (do_DataAbort) from [<c0100e00>] (__dabt_usr+0x40/0x60)
>
>> Zone ranges:
>>    Normal   [mem 0x0000000080a00000-0x00000000b01fffff]
>>    HighMem  [mem 0x00000000b0200000-0x00000000ffffefff]
>> Movable zone start for each node
>> Early memory node ranges
>>    node   0: [mem 0x0000000080a00000-0x00000000855fffff]
>>    node   0: [mem 0x0000000086a00000-0x0000000087dfffff]
>>    node   0: [mem 0x000000008bd00000-0x000000008c4fffff]
>>    node   0: [mem 0x000000008e300000-0x000000008ecfffff]
>>    node   0: [mem 0x0000000090d00000-0x00000000bfffffff]
>>    node   0: [mem 0x00000000cc000000-0x00000000dc9fffff]
>>    node   0: [mem 0x00000000de700000-0x00000000de9fffff]
>>    node   0: [mem 0x00000000e0800000-0x00000000e0bfffff]
>>    node   0: [mem 0x00000000f4b00000-0x00000000f6ffffff]
>>    node   0: [mem 0x00000000fda00000-0x00000000ffffefff]
>>
>> ----> free_memmap, start_pfn = 85800,  85800000 end_pfn = 86a00, 86a00000
>> ----> free_memmap, start_pfn = 8c800,  8c800000 end_pfn = 8e300, 8e300000
>> ----> free_memmap, start_pfn = 8f000,  8f000000 end_pfn = 90000, 90000000
>> ----> free_memmap, start_pfn = dcc00,  dcc00000 end_pfn = de700, de700000
>> ----> free_memmap, start_pfn = dec00,  dec00000 end_pfn = e0000, e0000000
>> ----> free_memmap, start_pfn = e0c00,  e0c00000 end_pfn = e4000, e4000000
>> ----> free_memmap, start_pfn = f7000,  f7000000 end_pfn = f8000, f8000000
>> === >move_freepages: start_pfn/end_pfn [de601, de7ff], [de600000, de7ff000]
>> :  pfn =de600 pfn2phy = de600000 , page = ef3cc000, page-flags = ffffffff
>> 8<--- cut here ---
>> Unable to handle kernel paging request at virtual address fffffffe
>> pgd = 5dd50df5
>> [fffffffe] *pgd=affff861, *pte=00000000, *ppte=00000000
>> Internal error: Oops: 37 [#1] SMP ARM
>> Modules linked in: gmac(O)
>> CPU: 2 PID: 635 Comm: test-oom Tainted: G           O      5.10.0+ #31
>> Hardware name: Hisilicon A9
>> PC is at move_freepages_block+0x150/0x278
>> LR is at move_freepages_block+0x150/0x278
>> pc : [<c02383a4>]    lr : [<c02383a4>]    psr: 200e0393
>> sp : c4179cf8  ip : 00000000  fp : 00000001
>> r10: c4179d58  r9 : 000de7ff  r8 : 00000000
>> r7 : c0863280  r6 : 000de600  r5 : 000de600  r4 : ef3cc000
>> r3 : ffffffff  r2 : 00000000  r1 : ef5d069c  r0 : fffffffe
>> Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
>> Control: 1ac5387d  Table: 83b0c04a  DAC: 55555555
>> Process test-oom (pid: 635, stack limit = 0x25d667df)
>>