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BUG: KCSAN: data-race in __filemap_remove_folio / nr_blockdev_pages

read-write to 0xffff88810048af78 of 8 bytes by task 25216 on cpu 1:
 page_cache_delete mm/filemap.c:147 [inline]
 __filemap_remove_folio+0x218/0x2e0 mm/filemap.c:228
 __remove_mapping+0x396/0x4c0 mm/vmscan.c:768
 remove_mapping+0x22/0x90 mm/vmscan.c:804
 mapping_evict_folio mm/truncate.c:339 [inline]
 mapping_try_invalidate+0x293/0x430 mm/truncate.c:560
 invalidate_mapping_pages+0x27/0x40 mm/truncate.c:602
 invalidate_bdev+0x58/0x70 block/bdev.c:102
 ext4_put_super+0x614/0x7c0 fs/ext4/super.c:1355
 generic_shutdown_super+0xee/0x220 fs/super.c:646
 kill_block_super+0x2a/0x70 fs/super.c:1725
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7492
 deactivate_locked_super+0x75/0x1c0 fs/super.c:476
 deactivate_super+0x97/0xa0 fs/super.c:509
 cleanup_mnt+0x2c3/0x340 fs/namespace.c:1312
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1319
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0x209/0x870 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810048af78 of 8 bytes by task 7926 on cpu 0:
 nr_blockdev_pages+0x7e/0xd0 block/bdev.c:531
 si_meminfo+0x87/0xd0 mm/show_mem.c:80
 update_defense_level+0x44/0x5c0 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:3314 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3397
 worker_thread+0x569/0x750 kernel/workqueue.c:3478
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000000000008 -> 0x0000000000000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7926 Comm: kworker/0:12 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_long defense_work_handler
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