syzbot

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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881005fd078 of 8 bytes by task 2967 on cpu 1:
 __filemap_add_folio+0x5b9/0x7d0 mm/filemap.c:919
 filemap_add_folio+0x1d9/0x360 mm/filemap.c:966
 __filemap_get_folio_mpol+0x326/0x650 mm/filemap.c:2016
 __filemap_get_folio include/linux/pagemap.h:763 [inline]
 grow_dev_folio fs/buffer.c:1050 [inline]
 grow_buffers fs/buffer.c:1116 [inline]
 __getblk_slow fs/buffer.c:1134 [inline]
 bdev_getblk+0x174/0x3f0 fs/buffer.c:1461
 __getblk include/linux/buffer_head.h:380 [inline]
 jbd2_journal_get_descriptor_buffer+0xce/0x210 fs/jbd2/journal.c:976
 write_one_revoke_record fs/jbd2/revoke.c:610 [inline]
 jbd2_journal_write_revoke_records+0x2f5/0x630 fs/jbd2/revoke.c:554
 jbd2_journal_commit_transaction+0x975/0x3150 fs/jbd2/commit.c:551
 kjournald2+0x211/0x3d0 fs/jbd2/journal.c:201
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff8881005fd078 of 8 bytes by task 3494 on cpu 0:
 nr_blockdev_pages+0x7e/0xd0 block/bdev.c:540
 si_meminfo+0x87/0xd0 mm/show_mem.c:80
 update_defense_level+0x47/0x5c0 net/netfilter/ipvs/ip_vs_ctl.c:101
 defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:234
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0x00000000000002af -> 0x00000000000002b0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3494 Comm: kworker/0:9 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_long defense_work_handler
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