syzbot

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BUG: KCSAN: data-race in isolate_migratepages_block / isolate_migratepages_block

write to 0xffff88823fffad90 of 8 bytes by task 18878 on cpu 1:
 update_cached_migrate mm/compaction.c:434 [inline]
 isolate_migratepages_block+0x18b7/0x1a90 mm/compaction.c:1122
 isolate_migratepages mm/compaction.c:1892 [inline]
 compact_zone+0x1587/0x1da0 mm/compaction.c:2342
 compact_zone_order mm/compaction.c:2485 [inline]
 try_to_compact_pages+0x317/0x840 mm/compaction.c:2543
 __alloc_pages_direct_compact+0x65/0x320 mm/page_alloc.c:4155
 __alloc_pages_slowpath+0x29a/0xb70 mm/page_alloc.c:4734
 __alloc_pages_nodemask+0x242/0x310 mm/page_alloc.c:5020
 alloc_pages_current+0x21d/0x310 mm/mempolicy.c:2277
 alloc_pages include/linux/gfp.h:561 [inline]
 __get_free_pages+0x8/0x30 mm/page_alloc.c:5044
 io_mem_alloc fs/io_uring.c:8063 [inline]
 io_allocate_scq_urings fs/io_uring.c:9410 [inline]
 io_uring_create+0x860/0x17d0 fs/io_uring.c:9548
 io_uring_setup fs/io_uring.c:9632 [inline]
 __do_sys_io_uring_setup fs/io_uring.c:9638 [inline]
 __se_sys_io_uring_setup fs/io_uring.c:9635 [inline]
 __x64_sys_io_uring_setup+0xe1/0x120 fs/io_uring.c:9635
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88823fffad90 of 8 bytes by task 18842 on cpu 0:
 update_cached_migrate mm/compaction.c:433 [inline]
 isolate_migratepages_block+0x188e/0x1a90 mm/compaction.c:1122
 isolate_migratepages mm/compaction.c:1892 [inline]
 compact_zone+0x1587/0x1da0 mm/compaction.c:2342
 compact_zone_order mm/compaction.c:2485 [inline]
 try_to_compact_pages+0x317/0x840 mm/compaction.c:2543
 __alloc_pages_direct_compact+0x65/0x320 mm/page_alloc.c:4155
 __alloc_pages_slowpath+0x29a/0xb70 mm/page_alloc.c:4734
 __alloc_pages_nodemask+0x242/0x310 mm/page_alloc.c:5020
 alloc_pages_current+0x21d/0x310 mm/mempolicy.c:2277
 alloc_pages include/linux/gfp.h:561 [inline]
 __get_free_pages+0x8/0x30 mm/page_alloc.c:5044
 io_mem_alloc fs/io_uring.c:8063 [inline]
 io_allocate_scq_urings fs/io_uring.c:9430 [inline]
 io_uring_create+0x991/0x17d0 fs/io_uring.c:9548
 io_uring_setup fs/io_uring.c:9632 [inline]
 __do_sys_io_uring_setup fs/io_uring.c:9638 [inline]
 __se_sys_io_uring_setup fs/io_uring.c:9635 [inline]
 __x64_sys_io_uring_setup+0xe1/0x120 fs/io_uring.c:9635
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18842 Comm: syz-executor.1 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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