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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881005a4608 of 8 bytes by task 13656 on cpu 0:
 __filemap_add_folio+0x38c/0x720 mm/filemap.c:904
 filemap_add_folio+0x6f/0x150 mm/filemap.c:939
 __filemap_get_folio+0x554/0x750 mm/filemap.c:1981
 pagecache_get_page+0x2a/0xd0 mm/folio-compat.c:99
 find_or_create_page include/linux/pagemap.h:632 [inline]
 grow_dev_page fs/buffer.c:989 [inline]
 grow_buffers fs/buffer.c:1054 [inline]
 __getblk_slow fs/buffer.c:1081 [inline]
 __getblk_gfp+0x182/0x7e0 fs/buffer.c:1376
 sb_getblk_gfp include/linux/buffer_head.h:366 [inline]
 ext4_sb_breadahead_unmovable+0x41/0x190 fs/ext4/super.c:257
 ext4_group_desc_init+0x5a1/0x13d0 fs/ext4/super.c:4770
 __ext4_fill_super fs/ext4/super.c:5225 [inline]
 ext4_fill_super+0x2cf6/0x43f0 fs/ext4/super.c:5637
 get_tree_bdev+0x2b1/0x3a0 fs/super.c:1303
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5668
 vfs_get_tree+0x51/0x190 fs/super.c:1510
 do_new_mount+0x200/0x650 fs/namespace.c:3039
 path_mount+0x498/0xb40 fs/namespace.c:3369
 do_mount fs/namespace.c:3382 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3568
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3568
 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 0xffff8881005a4608 of 8 bytes by task 3164 on cpu 1:
 nr_blockdev_pages+0x7f/0xd0 block/bdev.c:445
 si_meminfo+0x3e/0x60 mm/page_alloc.c:6021
 update_defense_level+0x43/0x580 net/netfilter/ipvs/ip_vs_ctl.c:101
 defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
 process_one_work+0x3e6/0x750 kernel/workqueue.c:2390
 worker_thread+0x5f2/0xa10 kernel/workqueue.c:2537
 kthread+0x1d7/0x210 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

value changed: 0x0000000000000001 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3164 Comm: kworker/1:5 Not tainted 6.3.0-syzkaller-00436-g173ea743bf7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Workqueue: events_long defense_work_handler
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