syzbot

==================================================================
BUG: KCSAN: data-race in __delete_from_page_cache / nr_blockdev_pages

write to 0xffff888129e87350 of 8 bytes by task 5073 on cpu 1:
 page_cache_delete mm/filemap.c:154 [inline]
 __delete_from_page_cache+0x282/0x380 mm/filemap.c:239
 __remove_mapping+0x3e2/0x490 mm/vmscan.c:928
 remove_mapping+0x22/0x60 mm/vmscan.c:950
 invalidate_complete_page mm/truncate.c:215 [inline]
 invalidate_inode_page+0x15d/0x190 mm/truncate.c:264
 invalidate_mapping_pages+0x3eb/0x720 mm/truncate.c:607
 invalidate_bdev+0x61/0x70 fs/block_dev.c:97
 blk_drop_partitions+0x5c/0x1e0 block/partitions/core.c:626
 bdev_disk_changed+0x88/0x320 fs/block_dev.c:1392
 blkdev_reread_part block/ioctl.c:103 [inline]
 blkdev_common_ioctl+0xd00/0x10b0 block/ioctl.c:549
 blkdev_ioctl+0x167/0x410 block/ioctl.c:618
 block_ioctl+0x6d/0x80 fs/block_dev.c:1871
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888129e87350 of 8 bytes by task 29897 on cpu 0:
 nr_blockdev_pages+0x7c/0xd0 fs/block_dev.c:914
 si_meminfo+0x3a/0x60 mm/page_alloc.c:5258
 update_defense_level+0x34/0x550 net/netfilter/ipvs/ip_vs_ctl.c:101
 defense_work_handler+0x1b/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29897 Comm: kworker/0:14 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_long defense_work_handler
==================================================================