Re: compaction: VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn))

[Baoquan He]

On 04/23/20 at 05:25pm, Qian Cai wrote:
> Compaction starts to crash below on linux-next today. The faulty page belongs to Node 0 DMA32 zone.
> Iâll continue to narrow it down, but just want to give a headup in case someone could beat me to it.
> 
> Debug output from free_area_init_core()
> [    0.000000] KK start page = ffffea0000000040, end page = ffffea0000040000, nid = 0 DMA
> [    0.000000] KK start page = ffffea0000040000, end page = ffffea0004000000, nid = 0 DMA32
> [    0.000000] KK start page = ffffea0004000000, end page = ffffea0012000000, nid = 0 NORMAL
> [    0.000000] KK start page = ffffea0012000000, end page = ffffea0021fc0000, nid = 4 NORMAL

Where are these printed? They are the direct mapping address of page?

> 
> I donât understand how it could end up in such a situation. There are several recent patches look
> more related than some others.
> 
> - mm: rework free_area_init*() funcitons
> https://lore.kernel.org/linux-mm/20200412194859.12663-1-rppt@xxxxxxxxxx/
> Could this somehow allow an invalid pfn to escape into the page allocator?
> Especially, is it related to skip the checks in memmap_init_zone()?
> https://lore.kernel.org/linux-mm/20200412194859.12663-16-rppt@xxxxxxxxxx

Possibly. In which arch is this happening? Do you have boot log?

> 
> # numactl -H
> available: 8 nodes (0-7)
> node 0 cpus: 0 1 16 17
> node 0 size: 7951 MB
> node 0 free: 4445 MB
> node 1 cpus: 2 3 18 19
> node 1 size: 0 MB
> node 1 free: 0 MB
> node 2 cpus: 4 5 20 21
> node 2 size: 0 MB
> node 2 free: 0 MB
> node 3 cpus: 6 7 22 23
> node 3 size: 0 MB
> node 3 free: 0 MB
> node 4 cpus: 8 9 24 25
> node 4 size: 15354 MB
> node 4 free: 78 MB
> node 5 cpus: 10 11 26 27
> node 5 size: 0 MB
> node 5 free: 0 MB
> node 6 cpus: 12 13 28 29
> node 6 size: 0 MB
> node 6 free: 0 MB
> node 7 cpus: 14 15 30 31
> node 7 size: 0 MB
> node 7 free: 0 MB
> node distances:
> node   0   1   2   3   4   5   6   7 
>   0:  10  16  16  16  32  32  32  32 
>   1:  16  10  16  16  32  32  32  32 
>   2:  16  16  10  16  32  32  32  32 
>   3:  16  16  16  10  32  32  32  32 
>   4:  32  32  32  32  10  16  16  16 
>   5:  32  32  32  32  16  10  16  16 
>   6:  32  32  32  32  16  16  10  16 
>   7:  32  32  32  32  16  16  16  10
> 
> [ 6803.941550] LTP: starting swapping01 (swapping01 -i 5)
> [ 6821.098489] page:ffffea0000aa0000 refcount:1 mapcount:0 mapping:000000002243743b index:0x0
> [ 6821.107077] flags: 0x1fffe000001000(reserved)
> [ 6821.111534] raw: 001fffe000001000 ffffea0000aa0008 ffffea0000aa0008 0000000000000000
> [ 6821.119365] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> [ 6821.127167] page dumped because: VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn))
> [ 6821.135399] page_owner info is not present (never set?)
> [ 6821.140717] ------------[ cut here ]------------
> [ 6821.145372] kernel BUG at mm/page_alloc.c:533!
> [ 6821.150075] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
> [ 6821.150083] irq event stamp: 10075005
> [ 6821.150102] hardirqs last  enabled at (10075005): [<ffffffff99ea403f>] do_page_fault+0x45f/0x9d7
> [ 6821.156829] CPU: 17 PID: 218 Comm: kcompactd0 Not tainted 5.7.0-rc2-next-20200423+ #7
> [ 6821.160522] hardirqs last disabled at (10075004): [<ffffffff99e03ed1>] trace_hardirqs_off_thunk+0x1a/0x1c
> [ 6821.160535] softirqs last  enabled at (10067158): [<ffffffff9ac00478>] __do_softirq+0x478/0x77f
> [ 6821.169366] Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 03/09/2018
> [ 6821.169378] RIP: 0010:set_pfnblock_flags_mask+0x150/0x210
> [ 6821.177257] softirqs last disabled at (10067149): [<ffffffff99ed22a6>] irq_exit+0xd6/0xf0
> [ 6821.218362] Code: 1a 49 8d 7f 38 e8 80 ee 05 00 48 8b 45 a0 48 8b 55 a8 48 03 50 78 49 39 d4 72 1d 48 c7 c6 80 ee ef 9a 4c 89 ef e8 70 73 fb ff <0f> 0b 48 c7 c7 40 50 75 9b e8 c4 09 2b 00 4c 8b 65 d0 b9 3f 00 00
> [ 6821.237457] RSP: 0018:ffffc900042ff858 EFLAGS: 00010282
> [ 6821.242719] RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff9a002382
> [ 6821.249900] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8884535b8e6c
> [ 6821.257384] RBP: ffffc900042ff8b8 R08: ffffed108a6b8459 R09: ffffed108a6b8459
> [ 6821.264566] R10: ffff8884535c22c7 R11: ffffed108a6b8458 R12: 000000000002a800
> [ 6821.271748] R13: ffffea0000aa0000 R14: ffff88847fff3000 R15: ffff88847fff3040
> [ 6821.278930] FS:  0000000000000000(0000) GS:ffff888453580000(0000) knlGS:0000000000000000
> [ 6821.287318] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 6821.293102] CR2: 00007fd1eb4a1000 CR3: 000000083154c000 CR4: 00000000003406e0
> [ 6821.300283] Call Trace:
> [ 6821.302752]  isolate_freepages+0xb20/0x1140
> [ 6821.307167]  ? isolate_freepages_block+0x730/0x730
> [ 6821.311993]  ? mark_held_locks+0x34/0xb0
> [ 6821.315942]  ? free_unref_page+0x7d/0x90
> [ 6821.319891]  ? free_unref_page+0x7d/0x90
> [ 6821.323842]  ? check_flags.part.28+0x86/0x220
> [ 6821.328234]  compaction_alloc+0xdd/0x100
> [ 6821.332401]  migrate_pages+0x304/0x17e0
> [ 6821.336277]  ? __ClearPageMovable+0x100/0x100
> [ 6821.340674]  ? isolate_freepages+0x1140/0x1140
> [ 6821.345153]  compact_zone+0x1249/0x1e90
> [ 6821.349020]  ? compaction_suitable+0x260/0x260
> [ 6821.353494]  kcompactd_do_work+0x231/0x650
> [ 6821.357873]  ? sysfs_compact_node+0x80/0x80
> [ 6821.362088]  ? finish_wait+0xe6/0x110
> [ 6821.365775]  kcompactd+0x162/0x490
> [ 6821.369202]  ? kcompactd_do_work+0x650/0x650
> [ 6821.373501]  ? finish_wait+0x110/0x110
> [ 6821.377280]  ? __kasan_check_read+0x11/0x20
> [ 6821.381693]  ? __kthread_parkme+0xd4/0xf0
> [ 6821.385729]  ? kcompactd_do_work+0x650/0x650
> [ 6821.390027]  kthread+0x1f7/0x220
> [ 6821.393280]  ? kthread_create_worker_on_cpu+0xc0/0xc0
> [ 6821.398369]  ret_from_fork+0x27/0x50
> [ 6821.401968] Modules linked in: brd vfat fat ext4 crc16 mbcache jbd2 loop kvm_amd ses kvm enclosure dax_pmem dax_pmem_core irqbypass acpi_cpufreq ip_tables x_tables xfs sd_mod smartpqi scsi_transport_sas tg3 firmware_class libphy dm_mirror dm_region_hash dm_log dm_mod
> [ 6821.426127] ---[ end trace 9783087562801ccf ]---
> [ 6821.430800] RIP: 0010:set_pfnblock_flags_mask+0x150/0x210
> [ 6821.436410] Code: 1a 49 8d 7f 38 e8 80 ee 05 00 48 8b 45 a0 48 8b 55 a8 48 03 50 78 49 39 d4 72 1d 48 c7 c6 80 ee ef 9a 4c 89 ef e8 70 73 fb ff <0f> 0b 48 c7 c7 40 50 75 9b e8 c4 09 2b 00 4c 8b 65 d0 b9 3f 00 00
> [ 6821.455319] RSP: 0018:ffffc900042ff858 EFLAGS: 00010282
> [ 6821.460863] RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff9a002382
> [ 6821.468063] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8884535b8e6c
> [ 6821.475245] RBP: ffffc900042ff8b8 R08: ffffed108a6b8459 R09: ffffed108a6b8459
> [ 6821.482675] R10: ffff8884535c22c7 R11: ffffed108a6b8458 R12: 000000000002a800
> [ 6821.489877] R13: ffffea0000aa0000 R14: ffff88847fff3000 R15: ffff88847fff3040
> [ 6821.497062] FS:  0000000000000000(0000) GS:ffff888453580000(0000) knlGS:0000000000000000
> [ 6821.505218] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 6821.511284] CR2: 00007fd1eb4a1000 CR3: 000000083154c000 CR4: 00000000003406e0
> [ 6821.518487] Kernel panic - not syncing: Fatal exception
> [ 6821.523876] Kernel Offset: 0x18e00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
> [ 6821.534915] ---[ end Kernel panic - not syncing: Fatal exception ]---
>