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BUG: KCSAN: data-race in isolate_migratepages_block / isolate_migratepages_block

write to 0xffff88812fffcc18 of 8 bytes by task 7945 on cpu 0:
 update_cached_migrate mm/compaction.c:421 [inline]
 isolate_migratepages_block+0x94f/0x1700 mm/compaction.c:1060
 isolate_migratepages mm/compaction.c:1820 [inline]
 compact_zone+0xcde/0x1f80 mm/compaction.c:2172
 compact_zone_order+0x1ce/0x240 mm/compaction.c:2316
 try_to_compact_pages+0x1bb/0x610 mm/compaction.c:2368
 __alloc_pages_direct_compact+0x85/0x160 mm/page_alloc.c:3901
 __alloc_pages_slowpath+0x4ee/0xee0 mm/page_alloc.c:4568
 __alloc_pages_nodemask+0x2c8/0x310 mm/page_alloc.c:4776
 __alloc_pages include/linux/gfp.h:496 [inline]
 __alloc_pages_node include/linux/gfp.h:509 [inline]
 alloc_pages_vma+0x2a6/0x3a0 mm/mempolicy.c:2151
 do_huge_pmd_anonymous_page+0x2ca/0xff0 mm/huge_memory.c:758
 create_huge_pmd mm/memory.c:3836 [inline]
 __handle_mm_fault+0x1d78/0x2e00 mm/memory.c:4046
 handle_mm_fault+0x21b/0x530 mm/memory.c:4112
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x456/0x8d0 arch/x86/mm/fault.c:1506
 do_page_fault+0x38/0x194 arch/x86/mm/fault.c:1530
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203

read to 0xffff88812fffcc18 of 8 bytes by task 7957 on cpu 1:
 update_cached_migrate mm/compaction.c:420 [inline]
 isolate_migratepages_block+0x927/0x1700 mm/compaction.c:1060
 isolate_migratepages mm/compaction.c:1820 [inline]
 compact_zone+0xcde/0x1f80 mm/compaction.c:2172
 compact_zone_order+0x1ce/0x240 mm/compaction.c:2316
 try_to_compact_pages+0x1bb/0x610 mm/compaction.c:2368
 __alloc_pages_direct_compact+0x85/0x160 mm/page_alloc.c:3901
 __alloc_pages_slowpath+0x4ee/0xee0 mm/page_alloc.c:4568
 __alloc_pages_nodemask+0x2c8/0x310 mm/page_alloc.c:4776
 __alloc_pages include/linux/gfp.h:496 [inline]
 __alloc_pages_node include/linux/gfp.h:509 [inline]
 alloc_pages_vma+0x2a6/0x3a0 mm/mempolicy.c:2151
 do_huge_pmd_anonymous_page+0x2ca/0xff0 mm/huge_memory.c:758
 create_huge_pmd mm/memory.c:3836 [inline]
 __handle_mm_fault+0x1d78/0x2e00 mm/memory.c:4046
 handle_mm_fault+0x21b/0x530 mm/memory.c:4112
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x456/0x8d0 arch/x86/mm/fault.c:1506
 do_page_fault+0x38/0x194 arch/x86/mm/fault.c:1530
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7957 Comm: syz-fuzzer Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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