EXT4-fs (loop4): Invalid log block size: 255
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BUG: KCSAN: data-race in has_bh_in_lru / invalidate_bh_lrus_cpu

write to 0xffff888237c42f10 of 8 bytes by task 30801 on cpu 0:
 __invalidate_bh_lrus fs/buffer.c:1393 [inline]
 invalidate_bh_lrus_cpu+0xad/0xe0 fs/buffer.c:1434
 lru_add_drain_cpu+0x243/0x270 mm/swap.c:645
 lru_add_drain+0x28/0x40 mm/swap.c:724
 exit_mmap+0x208/0x460 mm/mmap.c:3196
 __mmput+0x27/0x1c0 kernel/fork.c:1101
 mmput+0x3d/0x50 kernel/fork.c:1122
 free_bprm+0xce/0x1f0 fs/exec.c:1479
 kernel_execve+0x4e9/0x640 fs/exec.c:1976
 call_usermodehelper_exec_async+0x1d8/0x290 kernel/umh.c:112
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

read to 0xffff888237c42f10 of 8 bytes by task 30774 on cpu 1:
 has_bh_in_lru+0x31/0x1c0 fs/buffer.c:1415
 smp_call_function_many_cond+0x226/0x620 kernel/smp.c:915
 on_each_cpu_cond_mask+0x31/0x40 kernel/smp.c:1133
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x26/0x30 fs/buffer.c:1424
 invalidate_bdev+0x4b/0x70 fs/block_dev.c:95
 __loop_clr_fd+0x566/0x8f0 drivers/block/loop.c:1402
 loop_clr_fd drivers/block/loop.c:1496 [inline]
 lo_ioctl+0xa48/0x1340 drivers/block/loop.c:1852
 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585
 block_ioctl+0x6d/0x80 fs/block_dev.c:1604
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 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: 0xffff888106876750 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 30774 Comm: syz-executor.4 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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