FAT-fs (loop4): count of clusters too big (1048574)
FAT-fs (loop4): Can't find a valid FAT filesystem
==================================================================
BUG: KCSAN: data-race in has_bh_in_lru / invalidate_bh_lru

write to 0xffff888237c22f10 of 8 bytes by task 2369 on cpu 0:
 __invalidate_bh_lrus fs/buffer.c:1393 [inline]
 invalidate_bh_lru+0x8d/0xc0 fs/buffer.c:1405
 smp_call_function_many_cond+0x496/0x620 kernel/smp.c:960
 on_each_cpu_cond_mask+0x31/0x40 kernel/smp.c:1135
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x26/0x30 fs/buffer.c:1424
 invalidate_bdev+0x51/0x80 block/bdev.c:86
 __loop_clr_fd+0x521/0x850 drivers/block/loop.c:1399
 loop_clr_fd drivers/block/loop.c:1494 [inline]
 lo_ioctl+0xac5/0x13e0 drivers/block/loop.c:1850
 blkdev_ioctl+0x1d0/0x3f0 block/ioctl.c:589
 block_ioctl+0x6e/0x80 block/fops.c:478
 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+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c22f10 of 8 bytes by task 2378 on cpu 1:
 has_bh_in_lru+0x31/0x1c0 fs/buffer.c:1415
 smp_call_function_many_cond+0x236/0x620 kernel/smp.c:917
 on_each_cpu_cond_mask+0x31/0x40 kernel/smp.c:1135
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x26/0x30 fs/buffer.c:1424
 invalidate_bdev+0x51/0x80 block/bdev.c:86
 __loop_clr_fd+0x521/0x850 drivers/block/loop.c:1399
 loop_clr_fd drivers/block/loop.c:1494 [inline]
 lo_ioctl+0xac5/0x13e0 drivers/block/loop.c:1850
 blkdev_ioctl+0x1d0/0x3f0 block/ioctl.c:589
 block_ioctl+0x6e/0x80 block/fops.c:478
 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+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff888105d52a90 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2378 Comm: syz-executor.4 Not tainted 5.15.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
loop4: detected capacity change from 0 to 256
FAT-fs (loop4): count of clusters too big (1048574)
FAT-fs (loop4): Can't find a valid FAT filesystem