syzbot

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BUG: KCSAN: data-race in __loop_clr_fd / disk_removable_show

read to 0xffff88812a0a2c18 of 4 bytes by task 13126 on cpu 0:
 disk_removable_show+0x27/0x50 block/genhd.c:1137
 dev_attr_show+0x4a/0x90 drivers/base/core.c:1225
 sysfs_kf_seq_show+0x168/0x280 fs/sysfs/file.c:60
 kernfs_seq_show+0xaa/0xe0 fs/kernfs/file.c:167
 seq_read+0x350/0x9d0 fs/seq_file.c:229
 kernfs_fop_read+0xa2/0x350 fs/kernfs/file.c:251
 __vfs_read+0x67/0xc0 fs/read_write.c:425
 vfs_read fs/read_write.c:461 [inline]
 vfs_read+0x143/0x2c0 fs/read_write.c:446
 ksys_read+0xd5/0x1b0 fs/read_write.c:587
 __do_sys_read fs/read_write.c:597 [inline]
 __se_sys_read fs/read_write.c:595 [inline]
 __x64_sys_read+0x4c/0x60 fs/read_write.c:595
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88812a0a2c18 of 4 bytes by task 8023 on cpu 1:
 __loop_clr_fd+0x492/0x740 drivers/block/loop.c:1193
 lo_release+0x153/0x160 drivers/block/loop.c:1830
 __blkdev_put+0x2cf/0x420 fs/block_dev.c:1896
 blkdev_put+0x89/0x2f0 fs/block_dev.c:1958
 kill_block_super+0x90/0xb0 fs/super.c:1445
 deactivate_locked_super+0x64/0xb0 fs/super.c:335
 deactivate_super fs/super.c:366 [inline]
 deactivate_super+0xca/0xe0 fs/super.c:362
 cleanup_mnt+0x27f/0x330 fs/namespace.c:1102
 __cleanup_mnt+0x1f/0x30 fs/namespace.c:1109
 task_work_run+0xf6/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x384/0x3a0 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8023 Comm: syz-executor.2 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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