hid-generic 0000:0000:20000000.0011: hidraw0: <UNKNOWN> HID v0.01 Device [syz0] on syz1
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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881004c3db0 of 8 bytes by task 22147 on cpu 0:
 __filemap_add_folio+0x5b5/0x7f0 mm/filemap.c:928
 filemap_add_folio+0x9f/0x1b0 mm/filemap.c:969
 __filemap_get_folio+0x340/0x6b0 mm/filemap.c:1979
 grow_dev_folio fs/buffer.c:1039 [inline]
 grow_buffers fs/buffer.c:1105 [inline]
 __getblk_slow fs/buffer.c:1131 [inline]
 bdev_getblk+0x173/0x3b0 fs/buffer.c:1431
 ext4_sb_breadahead_unmovable+0x44/0x190 fs/ext4/super.c:270
 ext4_group_desc_init+0x5b6/0x12e0 fs/ext4/super.c:4870
 __ext4_fill_super fs/ext4/super.c:5349 [inline]
 ext4_fill_super+0x2210/0x3580 fs/ext4/super.c:5726
 get_tree_bdev_flags+0x2b4/0x330 fs/super.c:1636
 get_tree_bdev+0x1f/0x30 fs/super.c:1659
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5758
 vfs_get_tree+0x56/0x1e0 fs/super.c:1759
 do_new_mount+0x246/0x6b0 fs/namespace.c:3881
 path_mount+0x49b/0xb30 fs/namespace.c:4208
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4409
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4409
 x64_sys_call+0xd11/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881004c3db0 of 8 bytes by task 3381 on cpu 1:
 nr_blockdev_pages+0x7c/0xd0 block/bdev.c:485
 si_meminfo+0x87/0xd0 mm/show_mem.c:80
 update_defense_level+0x4b/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:3238 [inline]
 process_scheduled_works+0x4de/0xa20 kernel/workqueue.c:3319
 worker_thread+0x52c/0x710 kernel/workqueue.c:3400
 kthread+0x4b7/0x540 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000000000001 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3381 Comm: kworker/1:5 Not tainted 6.15.0-rc2-syzkaller-00048-gc62f4b82d571 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events_long defense_work_handler
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