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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881004c11f8 of 8 bytes by task 19377 on cpu 1:
 __filemap_add_folio+0x439/0x710 mm/filemap.c:918
 filemap_add_folio+0x9c/0x1b0 mm/filemap.c:970
 __filemap_get_folio+0x2f1/0x5b0 mm/filemap.c:1958
 grow_dev_folio fs/buffer.c:1049 [inline]
 grow_buffers fs/buffer.c:1115 [inline]
 __getblk_slow fs/buffer.c:1141 [inline]
 bdev_getblk+0x198/0x400 fs/buffer.c:1443
 __getblk include/linux/buffer_head.h:381 [inline]
 sb_getblk include/linux/buffer_head.h:387 [inline]
 ext4_getblk+0x1b4/0x500 fs/ext4/inode.c:843
 ext4_bread_batch+0x5b/0x360 fs/ext4/inode.c:910
 __ext4_find_entry+0x9d3/0x10a0 fs/ext4/namei.c:1670
 ext4_lookup_entry fs/ext4/namei.c:1770 [inline]
 ext4_lookup+0xba/0x390 fs/ext4/namei.c:1838
 lookup_open fs/namei.c:3483 [inline]
 open_last_lookups fs/namei.c:3574 [inline]
 path_openat+0xc5f/0x1fa0 fs/namei.c:3810
 do_filp_open+0xf7/0x200 fs/namei.c:3840
 do_sys_openat2+0xab/0x120 fs/open.c:1413
 do_sys_open fs/open.c:1428 [inline]
 __do_sys_creat fs/open.c:1504 [inline]
 __se_sys_creat fs/open.c:1498 [inline]
 __x64_sys_creat+0x66/0x90 fs/open.c:1498
 x64_sys_call+0x2365/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:86
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881004c11f8 of 8 bytes by task 4363 on cpu 0:
 nr_blockdev_pages+0x7c/0xd0 block/bdev.c:475
 si_meminfo+0x87/0xd0 mm/show_mem.c:80
 update_defense_level+0x49/0x5b0 net/netfilter/ipvs/ip_vs_ctl.c:102
 defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3329
 worker_thread+0x526/0x720 kernel/workqueue.c:3409
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x0000000000000003 -> 0x0000000000000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4363 Comm: kworker/0:7 Tainted: G        W          6.10.0-rc6-syzkaller-00051-g1dfe225e9af5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: events_long defense_work_handler
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