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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881004d6640 of 8 bytes by task 30712 on cpu 1:
 __filemap_add_folio+0x2d9/0x7f0 mm/filemap.c:904
 filemap_add_folio+0x6b/0x150 mm/filemap.c:959
 __filemap_get_folio+0x4bd/0x680 mm/filemap.c:2003
 pagecache_get_page+0x26/0x190 mm/folio-compat.c:126
 find_or_create_page include/linux/pagemap.h:615 [inline]
 grow_dev_page+0x74/0x540 fs/buffer.c:946
 grow_buffers fs/buffer.c:1011 [inline]
 __getblk_slow fs/buffer.c:1038 [inline]
 __getblk_gfp+0x112/0x1c0 fs/buffer.c:1333
 __bread_gfp+0x28/0x220 fs/buffer.c:1378
 sb_bread include/linux/buffer_head.h:302 [inline]
 isofs_read_level3_size fs/isofs/inode.c:1225 [inline]
 isofs_read_inode fs/isofs/inode.c:1387 [inline]
 __isofs_iget+0x6b1/0xff0 fs/isofs/inode.c:1552
 isofs_iget fs/isofs/isofs.h:133 [inline]
 isofs_fill_super+0x1280/0x17b0 fs/isofs/inode.c:910
 mount_bdev+0x1e2/0x280 fs/super.c:1367
 isofs_mount+0x2d/0x40 fs/isofs/inode.c:1567
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610
 vfs_get_tree+0x49/0x190 fs/super.c:1497
 do_new_mount+0x200/0x650 fs/namespace.c:3040
 path_mount+0x4b1/0xb60 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x281/0x2d0 fs/namespace.c:3568
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881004d6640 of 8 bytes by task 1913 on cpu 0:
 nr_blockdev_pages+0x7f/0xd0 block/bdev.c:517
 si_meminfo+0x3a/0x60 mm/page_alloc.c:5817
 update_defense_level+0x46/0x560 net/netfilter/ipvs/ip_vs_ctl.c:102
 defense_work_handler+0x1b/0x80 net/netfilter/ipvs/ip_vs_ctl.c:236
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x00000000000007c7 -> 0x00000000000007c8

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1913 Comm: kworker/0:4 Not tainted 5.18.0-rc4-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_long defense_work_handler
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