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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881005b0570 of 8 bytes by task 27184 on cpu 1:
 __filemap_add_folio+0x3c3/0x750 mm/filemap.c:904
 filemap_add_folio+0x70/0x160 mm/filemap.c:939
 page_cache_ra_unbounded+0x15e/0x2e0 mm/readahead.c:250
 do_page_cache_ra mm/readahead.c:299 [inline]
 force_page_cache_ra mm/readahead.c:330 [inline]
 page_cache_sync_ra+0x24b/0x2a0 mm/readahead.c:691
 page_cache_sync_readahead include/linux/pagemap.h:1293 [inline]
 filemap_get_pages+0x251/0xe90 mm/filemap.c:2556
 filemap_read+0x214/0x680 mm/filemap.c:2652
 blkdev_read_iter+0x217/0x2c0 block/fops.c:730
 call_read_iter include/linux/fs.h:1950 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x3da/0x5c0 fs/read_write.c:470
 ksys_read+0xeb/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+0x42/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881005b0570 of 8 bytes by task 12830 on cpu 0:
 nr_blockdev_pages+0x7c/0xd0 block/bdev.c:441
 si_meminfo+0x87/0xd0 mm/show_mem.c:83
 update_defense_level+0x46/0x600 net/netfilter/ipvs/ip_vs_ctl.c:101
 defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
 process_one_work kernel/workqueue.c:2630 [inline]
 process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2703
 worker_thread+0x525/0x730 kernel/workqueue.c:2784
 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:304

value changed: 0x0000000000000009 -> 0x000000000000000a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12830 Comm: kworker/0:0 Not tainted 6.6.0-rc6-syzkaller-00207-gc8045b4a33a5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: events_long defense_work_handler
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