syzbot

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BUG: KCSAN: data-race in compact_zone / compact_zone

write to 0xffff88812fffbc10 of 8 bytes by task 12360 on cpu 1:
 update_cached_migrate mm/compaction.c:418 [inline]
 isolate_migratepages mm/compaction.c:1826 [inline]
 compact_zone+0x13f8/0x1de0 mm/compaction.c:2183
 compact_zone_order mm/compaction.c:2327 [inline]
 try_to_compact_pages+0x28c/0x5b0 mm/compaction.c:2385
 __alloc_pages_direct_compact+0x89/0x170 mm/page_alloc.c:4000
 __alloc_pages_slowpath+0x596/0x970 mm/page_alloc.c:4656
 __alloc_pages_nodemask+0x235/0x390 mm/page_alloc.c:4863
 __alloc_pages include/linux/gfp.h:509 [inline]
 __alloc_pages_node include/linux/gfp.h:522 [inline]
 alloc_pages_node include/linux/gfp.h:536 [inline]
 alloc_new_node_page+0x129/0x160 mm/mempolicy.c:1077
 unmap_and_move+0x114/0x800 mm/migrate.c:1192
 migrate_pages+0x1ad/0xa30 mm/migrate.c:1444
 do_move_pages_to_node mm/migrate.c:1523 [inline]
 move_pages_and_store_status mm/migrate.c:1613 [inline]
 do_pages_move mm/migrate.c:1709 [inline]
 kernel_move_pages+0xa41/0xc00 mm/migrate.c:1842
 __do_sys_move_pages mm/migrate.c:1860 [inline]
 __se_sys_move_pages mm/migrate.c:1855 [inline]
 __x64_sys_move_pages+0x74/0x90 mm/migrate.c:1855
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812fffbc10 of 8 bytes by task 12358 on cpu 0:
 update_cached_migrate mm/compaction.c:417 [inline]
 isolate_migratepages mm/compaction.c:1826 [inline]
 compact_zone+0x13d3/0x1de0 mm/compaction.c:2183
 compact_zone_order mm/compaction.c:2327 [inline]
 try_to_compact_pages+0x28c/0x5b0 mm/compaction.c:2385
 __alloc_pages_direct_compact+0x89/0x170 mm/page_alloc.c:4000
 __alloc_pages_slowpath+0x596/0x970 mm/page_alloc.c:4656
 __alloc_pages_nodemask+0x235/0x390 mm/page_alloc.c:4863
 __alloc_pages include/linux/gfp.h:509 [inline]
 __alloc_pages_node include/linux/gfp.h:522 [inline]
 alloc_pages_node include/linux/gfp.h:536 [inline]
 alloc_new_node_page+0x129/0x160 mm/mempolicy.c:1077
 unmap_and_move+0x114/0x800 mm/migrate.c:1192
 migrate_pages+0x1ad/0xa30 mm/migrate.c:1444
 do_move_pages_to_node mm/migrate.c:1523 [inline]
 move_pages_and_store_status mm/migrate.c:1613 [inline]
 do_pages_move mm/migrate.c:1709 [inline]
 kernel_move_pages+0xa41/0xc00 mm/migrate.c:1842
 __do_sys_move_pages mm/migrate.c:1860 [inline]
 __se_sys_move_pages mm/migrate.c:1855 [inline]
 __x64_sys_move_pages+0x74/0x90 mm/migrate.c:1855
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12358 Comm: syz-executor.4 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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