syzbot

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BUG: KCSAN: data-race in isolate_migratepages_block / isolate_migratepages_block

write to 0xffff88823fffad90 of 8 bytes by task 14575 on cpu 0:
 update_cached_migrate mm/compaction.c:434 [inline]
 isolate_migratepages_block+0x1a9b/0x1d00 mm/compaction.c:1160
 isolate_migratepages mm/compaction.c:1930 [inline]
 compact_zone+0x1524/0x1ce0 mm/compaction.c:2376
 compact_zone_order mm/compaction.c:2519 [inline]
 try_to_compact_pages+0x317/0x840 mm/compaction.c:2585
 __alloc_pages_direct_compact+0x61/0x330 mm/page_alloc.c:4373
 __alloc_pages_slowpath+0x29a/0xb90 mm/page_alloc.c:4957
 __alloc_pages+0x25b/0x320 mm/page_alloc.c:5404
 alloc_pages+0x2e8/0x340 mm/mempolicy.c:2244
 __get_free_pages+0x8/0x30 mm/page_alloc.c:5428
 io_mem_alloc fs/io_uring.c:8169 [inline]
 io_allocate_scq_urings fs/io_uring.c:9559 [inline]
 io_uring_create+0x904/0x1940 fs/io_uring.c:9695
 io_uring_setup fs/io_uring.c:9785 [inline]
 __do_sys_io_uring_setup fs/io_uring.c:9791 [inline]
 __se_sys_io_uring_setup fs/io_uring.c:9788 [inline]
 __x64_sys_io_uring_setup+0xe1/0x120 fs/io_uring.c:9788
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88823fffad90 of 8 bytes by task 14574 on cpu 1:
 update_cached_migrate mm/compaction.c:433 [inline]
 isolate_migratepages_block+0x1a77/0x1d00 mm/compaction.c:1160
 isolate_migratepages mm/compaction.c:1930 [inline]
 compact_zone+0x1524/0x1ce0 mm/compaction.c:2376
 compact_zone_order mm/compaction.c:2519 [inline]
 try_to_compact_pages+0x317/0x840 mm/compaction.c:2585
 __alloc_pages_direct_compact+0x61/0x330 mm/page_alloc.c:4373
 __alloc_pages_slowpath+0x29a/0xb90 mm/page_alloc.c:4957
 __alloc_pages+0x25b/0x320 mm/page_alloc.c:5404
 alloc_pages+0x2e8/0x340 mm/mempolicy.c:2244
 __get_free_pages+0x8/0x30 mm/page_alloc.c:5428
 io_mem_alloc fs/io_uring.c:8169 [inline]
 io_allocate_scq_urings fs/io_uring.c:9577 [inline]
 io_uring_create+0x9f7/0x1940 fs/io_uring.c:9695
 io_uring_setup fs/io_uring.c:9785 [inline]
 __do_sys_io_uring_setup fs/io_uring.c:9791 [inline]
 __se_sys_io_uring_setup fs/io_uring.c:9788 [inline]
 __x64_sys_io_uring_setup+0xe1/0x120 fs/io_uring.c:9788
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000156c00 -> 0x000000000015be00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14574 Comm: syz-executor.2 Not tainted 5.14.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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