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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881004055c8 of 8 bytes by task 2112 on cpu 0:
 __filemap_add_folio+0x379/0x6e0 mm/filemap.c:899
 filemap_add_folio+0x6b/0x150 mm/filemap.c:934
 page_cache_ra_unbounded+0x1a0/0x320 mm/readahead.c:251
 do_page_cache_ra mm/readahead.c:300 [inline]
 force_page_cache_ra+0x1c6/0x200 mm/readahead.c:331
 page_cache_sync_ra+0xc8/0xf0 mm/readahead.c:705
 page_cache_sync_readahead include/linux/pagemap.h:1213 [inline]
 filemap_get_pages mm/filemap.c:2581 [inline]
 filemap_read+0x3fd/0x1510 mm/filemap.c:2675
 blkdev_read_iter+0x2c6/0x370 block/fops.c:598
 call_read_iter include/linux/fs.h:2193 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x3a5/0x560 fs/read_write.c:470
 ksys_read+0xe8/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881004055c8 of 8 bytes by task 78 on cpu 1:
 nr_blockdev_pages+0x7f/0xd0 block/bdev.c:523
 si_meminfo+0x3a/0x60 mm/page_alloc.c:5984
 update_defense_level+0x46/0x560 net/netfilter/ipvs/ip_vs_ctl.c:102
 defense_work_handler+0x1b/0x80 net/netfilter/ipvs/ip_vs_ctl.c:236
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

value changed: 0x0000000000000017 -> 0x0000000000000019

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 78 Comm: kworker/1:2 Not tainted 6.1.0-rc7-syzkaller-00012-gca57f02295f1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: events_long defense_work_handler
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