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BUG: KCSAN: data-race in lru_add_drain_all / lru_cache_add

write to 0xffff888237d264a8 of 1 bytes by task 13325 on cpu 1:
 pagevec_add include/linux/pagevec.h:74 [inline]
 lru_cache_add+0x74/0x130 mm/swap.c:461
 add_to_page_cache_lru+0x150/0x1b0 mm/filemap.c:999
 page_cache_ra_unbounded+0x262/0x410 mm/readahead.c:221
 ondemand_readahead+0x579/0x7b0 mm/readahead.c:267
 page_cache_async_ra+0x165/0x190 mm/readahead.c:607
 page_cache_async_readahead include/linux/pagemap.h:897 [inline]
 do_async_mmap_readahead+0x21a/0x260 mm/filemap.c:2946
 filemap_fault+0x106/0x7b0 mm/filemap.c:3000
 ext4_filemap_fault+0x4b/0x60 fs/ext4/inode.c:6194
 __do_fault mm/memory.c:3678 [inline]
 do_read_fault mm/memory.c:3980 [inline]
 do_fault mm/memory.c:4108 [inline]
 handle_pte_fault mm/memory.c:4367 [inline]
 __handle_mm_fault mm/memory.c:4502 [inline]
 handle_mm_fault+0xe8d/0x1a70 mm/memory.c:4600
 faultin_page mm/gup.c:907 [inline]
 __get_user_pages+0x947/0xee0 mm/gup.c:1126
 populate_vma_page_range mm/gup.c:1459 [inline]
 __mm_populate+0x24d/0x380 mm/gup.c:1507
 mm_populate include/linux/mm.h:2595 [inline]
 __do_sys_mlockall+0x24c/0x2d0 mm/mlock.c:798
 __se_sys_mlockall mm/mlock.c:774 [inline]
 __x64_sys_mlockall+0x1a/0x20 mm/mlock.c:774
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237d264a8 of 1 bytes by task 13283 on cpu 0:
 pagevec_count include/linux/pagevec.h:61 [inline]
 lru_add_drain_all+0x108/0x3b0 mm/swap.c:813
 migrate_prep+0xa/0x10 mm/migrate.c:73
 do_mbind+0x3f2/0xfc0 mm/mempolicy.c:1326
 kernel_mbind mm/mempolicy.c:1478 [inline]
 __do_sys_mbind mm/mempolicy.c:1485 [inline]
 __se_sys_mbind mm/mempolicy.c:1481 [inline]
 __x64_sys_mbind+0x142/0x170 mm/mempolicy.c:1481
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13283 Comm: syz-executor.4 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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