syzbot

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BUG: KCSAN: data-race in compact_zone / isolate_migratepages_block

read to 0xffff88823fffa8d8 of 8 bytes by task 31 on cpu 0:
 update_cached_migrate mm/compaction.c:475 [inline]
 isolate_migratepages_block+0x1da2/0x1f40 mm/compaction.c:1259
 isolate_migratepages mm/compaction.c:2052 [inline]
 compact_zone+0x1c6c/0x2720 mm/compaction.c:2508
 kcompactd_do_work mm/compaction.c:2992 [inline]
 kcompactd+0x4bf/0xfa0 mm/compaction.c:3091
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

write to 0xffff88823fffa8d8 of 8 bytes by task 28190 on cpu 1:
 compact_zone+0x21e8/0x2720 mm/compaction.c:2516
 compact_zone_order mm/compaction.c:2668 [inline]
 try_to_compact_pages+0x39b/0x930 mm/compaction.c:2729
 __alloc_pages_direct_compact+0x75/0x1f0 mm/page_alloc.c:3525
 __alloc_pages_slowpath+0x232/0xd90 mm/page_alloc.c:4119
 __alloc_pages+0x25d/0x340 mm/page_alloc.c:4581
 alloc_pages_mpol+0xb1/0x1d0 mm/mempolicy.c:2133
 alloc_pages+0xe0/0x100 mm/mempolicy.c:2204
 __get_free_pages+0xc/0x30 mm/page_alloc.c:4615
 io_mem_alloc io_uring/io_uring.c:2789 [inline]
 io_allocate_scq_urings+0x2b8/0x360 io_uring/io_uring.c:3842
 io_uring_create+0x537/0x920 io_uring/io_uring.c:4019
 io_uring_setup io_uring/io_uring.c:4131 [inline]
 __do_sys_io_uring_setup io_uring/io_uring.c:4158 [inline]
 __se_sys_io_uring_setup+0x1ce/0x1e0 io_uring/io_uring.c:4152
 __x64_sys_io_uring_setup+0x31/0x40 io_uring/io_uring.c:4152
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x000000000005c800 -> 0x000000000005cc00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28190 Comm: syz-executor.2 Not tainted 6.7.0-rc7-syzkaller-00041-gf016f7547aee #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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