syzbot

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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff888100481860 of 8 bytes by task 27903 on cpu 0:
 __filemap_add_folio+0x385/0x730 mm/filemap.c:907
 filemap_add_folio+0x6f/0x150 mm/filemap.c:942
 __filemap_get_folio+0x313/0x500 mm/filemap.c:1944
 grow_dev_page fs/buffer.c:1063 [inline]
 grow_buffers fs/buffer.c:1123 [inline]
 __getblk_slow fs/buffer.c:1150 [inline]
 __getblk_gfp+0x19b/0x710 fs/buffer.c:1445
 sb_getblk_gfp include/linux/buffer_head.h:376 [inline]
 ext4_sb_breadahead_unmovable+0x41/0x190 fs/ext4/super.c:257
 ext4_group_desc_init+0x5a1/0x13d0 fs/ext4/super.c:4866
 __ext4_fill_super fs/ext4/super.c:5299 [inline]
 ext4_fill_super+0x22de/0x38b0 fs/ext4/super.c:5696
 get_tree_bdev+0x2b4/0x3b0 fs/super.c:1318
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5728
 vfs_get_tree+0x51/0x190 fs/super.c:1519
 do_new_mount+0x203/0x660 fs/namespace.c:3335
 path_mount+0x496/0xb30 fs/namespace.c:3662
 do_mount fs/namespace.c:3675 [inline]
 __do_sys_mount fs/namespace.c:3884 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3861
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3861
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888100481860 of 8 bytes by task 884 on cpu 1:
 nr_blockdev_pages+0x7f/0xd0 block/bdev.c:458
 si_meminfo+0x87/0xd0 mm/show_mem.c:83
 update_defense_level+0x43/0x580 net/netfilter/ipvs/ip_vs_ctl.c:101
 defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
 process_one_work+0x434/0x860 kernel/workqueue.c:2600
 worker_thread+0x5f2/0xa10 kernel/workqueue.c:2751
 kthread+0x1d7/0x210 kernel/kthread.c:389
 ret_from_fork+0x2e/0x40 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

value changed: 0x0000000000000001 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 884 Comm: kworker/1:1 Not tainted 6.5.0-rc7-syzkaller-00024-g93f5de5f648d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events_long defense_work_handler
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