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BUG: KCSAN: data-race in activate_page / lru_add_drain_all

read to 0xffff88812c029760 of 1 bytes by task 22460 on cpu 1:
 need_activate_page_drain mm/swap.c:304 [inline]
 lru_add_drain_all+0x3a2/0x3d0 mm/swap.c:751
 invalidate_bdev+0x6e/0x90 fs/block_dev.c:97
 __invalidate_device+0x61/0x80 fs/block_dev.c:2233
 invalidate_partition+0x4c/0x70 block/genhd.c:1614
 blk_drop_partitions+0xf6/0x1a0 block/partition-generic.c:455
 bdev_disk_changed+0xdd/0x1a0 fs/block_dev.c:1519
 loop_reread_partitions+0x36/0x70 drivers/block/loop.c:644
 loop_set_status+0xa02/0xb30 drivers/block/loop.c:1356
 loop_set_status64+0x6d/0xb0 drivers/block/loop.c:1476
 lo_ioctl+0x30b/0xc80 drivers/block/loop.c:1619
 __blkdev_driver_ioctl block/ioctl.c:277 [inline]
 blkdev_ioctl+0xbe5/0x1260 block/ioctl.c:582
 block_ioctl+0x95/0xc0 fs/block_dev.c:1983
 vfs_ioctl fs/ioctl.c:47 [inline]
 file_ioctl fs/ioctl.c:545 [inline]
 do_vfs_ioctl+0x84f/0xcf0 fs/ioctl.c:732
 ksys_ioctl+0xbd/0xe0 fs/ioctl.c:749
 __do_sys_ioctl fs/ioctl.c:756 [inline]
 __se_sys_ioctl fs/ioctl.c:754 [inline]
 __x64_sys_ioctl+0x4c/0x60 fs/ioctl.c:754
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88812c029760 of 1 bytes by task 22471 on cpu 0:
 pagevec_add include/linux/pagevec.h:81 [inline]
 activate_page+0x24f/0x380 mm/swap.c:314
 mark_page_accessed+0x2ba/0x520 mm/swap.c:393
 shmem_file_read_iter+0x59c/0x720 mm/shmem.c:2605
 call_read_iter include/linux/fs.h:1896 [inline]
 do_iter_readv_writev+0x54b/0x5b0 fs/read_write.c:691
 do_iter_read+0x1fc/0x3d0 fs/read_write.c:933
 vfs_iter_read+0x5c/0x80 fs/read_write.c:947
 lo_read_simple drivers/block/loop.c:351 [inline]
 do_req_filebacked drivers/block/loop.c:625 [inline]
 loop_handle_cmd drivers/block/loop.c:1952 [inline]
 loop_queue_work+0x92c/0x1623 drivers/block/loop.c:1966
 kthread_worker_fn+0x1c3/0x3a0 kernel/kthread.c:671
 loop_kthread_worker_fn+0x50/0x70 drivers/block/loop.c:901
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 22471 Comm: loop2 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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