BTRFS warning (device loop0): couldn't read tree root
==================================================================
BUG: KCSAN: data-race in lru_add_drain_all / lru_cache_add

write to 0xffff88813bc27550 of 1 bytes by task 8402 on cpu 0:
 pagevec_add include/linux/pagevec.h:74 [inline]
 lru_cache_add+0x7c/0x160 mm/swap.c:461
 lru_cache_add_inactive_or_unevictable+0x46/0x160 mm/swap.c:493
 wp_page_copy+0x881/0x1570 mm/memory.c:2910
 do_wp_page+0x4cf/0x740 arch/x86/include/asm/atomic.h:95
 handle_pte_fault mm/memory.c:4336 [inline]
 __handle_mm_fault mm/memory.c:4453 [inline]
 handle_mm_fault+0x1463/0x1840 mm/memory.c:4551
 do_user_addr_fault+0x60c/0xc00 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x94/0x2a0 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:577

read to 0xffff88813bc27550 of 1 bytes by task 15506 on cpu 1:
 pagevec_count include/linux/pagevec.h:61 [inline]
 lru_add_drain_all+0x108/0x3c0 mm/swap.c:813
 invalidate_bdev+0x50/0x70 fs/block_dev.c:96
 btrfs_close_bdev fs/btrfs/volumes.c:1116 [inline]
 btrfs_close_one_device fs/btrfs/volumes.c:1135 [inline]
 close_fs_devices+0x25e/0x4d0 fs/btrfs/volumes.c:1165
 btrfs_close_devices+0x44/0x210 fs/btrfs/volumes.c:1180
 open_ctree+0x529/0x230b fs/btrfs/disk-io.c:3584
 btrfs_fill_super fs/btrfs/super.c:1356 [inline]
 btrfs_mount_root+0x742/0x830 fs/btrfs/super.c:1723
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:592
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1497
 fc_mount fs/namespace.c:993 [inline]
 vfs_kern_mount+0xc6/0x130 fs/namespace.c:1023
 btrfs_mount+0x278/0x740 fs/btrfs/super.c:1783
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:592
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1497
 do_new_mount fs/namespace.c:2903 [inline]
 path_mount+0x11b9/0x1c00 fs/namespace.c:3233
 do_mount fs/namespace.c:3246 [inline]
 __do_sys_mount fs/namespace.c:3454 [inline]
 __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3431
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3431
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15506 Comm: syz-executor.0 Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
BTRFS error (device loop0): open_ctree failed