syzbot

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BUG: KCSAN: data-race in __filemap_remove_folio / nr_blockdev_pages

read-write to 0xffff8881006324b0 of 8 bytes by task 10068 on cpu 0:
 page_cache_delete mm/filemap.c:145 [inline]
 __filemap_remove_folio+0x1c5/0x2c0 mm/filemap.c:223
 __remove_mapping+0x33f/0x470 mm/vmscan.c:798
 remove_mapping+0x22/0x90 mm/vmscan.c:831
 mapping_evict_folio mm/truncate.c:261 [inline]
 mapping_try_invalidate+0x265/0x3f0 mm/truncate.c:482
 invalidate_mapping_pages+0x27/0x40 mm/truncate.c:524
 invalidate_bdev+0x58/0x70 block/bdev.c:102
 ext4_put_super+0x571/0x810 fs/ext4/super.c:1356
 generic_shutdown_super+0xe5/0x220 fs/super.c:642
 kill_block_super+0x2a/0x70 fs/super.c:1710
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7368
 deactivate_locked_super+0x7d/0x1c0 fs/super.c:473
 deactivate_super+0x9f/0xb0 fs/super.c:506
 cleanup_mnt+0x268/0x2e0 fs/namespace.c:1413
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1420
 task_work_run+0x13a/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881006324b0 of 8 bytes by task 36 on cpu 1:
 nr_blockdev_pages+0x7c/0xd0 block/bdev.c:481
 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:3238 [inline]
 process_scheduled_works+0x4db/0xa20 kernel/workqueue.c:3319
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3400
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x0000000000000009 -> 0x0000000000000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 36 Comm: kworker/1:1 Not tainted 6.14.0-rc7-syzkaller-00137-g5fc319360819 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events_long defense_work_handler
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