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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881006311f0 of 8 bytes by task 1673 on cpu 1:
 __filemap_add_folio+0x4c1/0x730 mm/filemap.c:903
 filemap_add_folio+0x70/0x160 mm/filemap.c:938
 __filemap_get_folio+0x2f1/0x5a0 mm/filemap.c:1927
 grow_dev_folio fs/buffer.c:1042 [inline]
 grow_buffers fs/buffer.c:1108 [inline]
 __getblk_slow fs/buffer.c:1134 [inline]
 bdev_getblk+0x1a5/0x430 fs/buffer.c:1429
 ext4_sb_breadahead_unmovable+0x44/0x190 fs/ext4/super.c:264
 ext4_group_desc_init+0x5a1/0x1400 fs/ext4/super.c:4872
 __ext4_fill_super fs/ext4/super.c:5305 [inline]
 ext4_fill_super+0x23c6/0x39b0 fs/ext4/super.c:5703
 get_tree_bdev+0x250/0x2e0 fs/super.c:1614
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5735
 vfs_get_tree+0x53/0x1d0 fs/super.c:1779
 do_new_mount+0x227/0x690 fs/namespace.c:3352
 path_mount+0x496/0xb30 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3875
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881006311f0 of 8 bytes by task 28772 on cpu 0:
 nr_blockdev_pages+0x7c/0xd0 block/bdev.c:449
 si_meminfo+0x87/0xd0 mm/show_mem.c:80
 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:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 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:243

value changed: 0x0000000000000001 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28772 Comm: kworker/0:11 Not tainted 6.8.0-rc6-syzkaller-00011-g45ec2f5f6ed3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: events_long defense_work_handler
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