loop2: detected capacity change from 0 to 64
FAT-fs (loop2): invalid media value (0x00)
FAT-fs (loop2): Can't find a valid FAT filesystem
==================================================================
BUG: KCSAN: data-race in __lru_add_drain_all / lru_cache_add

write to 0xffff888237c22528 of 1 bytes by task 6279 on cpu 0:
 pagevec_add include/linux/pagevec.h:74 [inline]
 pagevec_add_and_need_flush mm/swap.c:244 [inline]
 lru_cache_add+0x75/0x150 mm/swap.c:474
 shmem_getpage_gfp+0xc9b/0x13e0 mm/shmem.c:1944
 shmem_getpage mm/shmem.c:155 [inline]
 shmem_write_begin+0x7e/0x100 mm/shmem.c:2482
 generic_perform_write+0x1a6/0x3d0 mm/filemap.c:3773
 __generic_file_write_iter+0x174/0x310 mm/filemap.c:3900
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3932
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x77d/0x8c0 fs/read_write.c:594
 ksys_pwrite64 fs/read_write.c:701 [inline]
 __do_sys_pwrite64 fs/read_write.c:711 [inline]
 __se_sys_pwrite64 fs/read_write.c:708 [inline]
 __x64_sys_pwrite64+0xf5/0x150 fs/read_write.c:708
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c22528 of 1 bytes by task 6274 on cpu 1:
 pagevec_count include/linux/pagevec.h:61 [inline]
 __lru_add_drain_all+0x12c/0x3e0 mm/swap.c:828
 lru_add_drain_all+0xc/0x10 mm/swap.c:850
 invalidate_bdev+0x56/0x80 fs/block_dev.c:97
 __loop_clr_fd+0x521/0x850 drivers/block/loop.c:1399
 loop_clr_fd drivers/block/loop.c:1494 [inline]
 lo_ioctl+0xa48/0x1370 drivers/block/loop.c:1850
 blkdev_ioctl+0x1d0/0x3e0 block/ioctl.c:589
 block_ioctl+0x6d/0x80 fs/block_dev.c:1421
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x09 -> 0x0a

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 6274 Comm: syz-executor.2 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================