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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881004c0bb8 of 8 bytes by task 9788 on cpu 0:
 __filemap_add_folio+0x461/0x6d0 mm/filemap.c:912
 filemap_add_folio+0x70/0x160 mm/filemap.c:947
 __filemap_get_folio+0x2f1/0x5b0 mm/filemap.c:1934
 grow_dev_folio fs/buffer.c:1042 [inline]
 grow_buffers fs/buffer.c:1108 [inline]
 __getblk_slow fs/buffer.c:1134 [inline]
 bdev_getblk+0x1a5/0x420 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:4867
 __ext4_fill_super fs/ext4/super.c:5300 [inline]
 ext4_fill_super+0x23c9/0x39d0 fs/ext4/super.c:5699
 get_tree_bdev+0x253/0x2e0 fs/super.c:1614
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5731
 vfs_get_tree+0x56/0x1d0 fs/super.c:1779
 do_new_mount+0x227/0x690 fs/namespace.c:3352
 path_mount+0x49b/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
 x64_sys_call+0x2591/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:166
 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+0x77/0x7f

read to 0xffff8881004c0bb8 of 8 bytes by task 31689 on cpu 1:
 nr_blockdev_pages+0x7c/0xd0 block/bdev.c:455
 si_meminfo+0x87/0xd0 mm/show_mem.c:80
 update_defense_level+0x46/0x610 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:3267 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3348
 worker_thread+0x526/0x730 kernel/workqueue.c:3429
 kthread+0x1d1/0x210 kernel/kthread.c:388
 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: 0x0000000000000001 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31689 Comm: kworker/1:2 Tainted: G        W          6.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events_long defense_work_handler
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