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)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)