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BUG: KCSAN: data-race in __kernfs_remove / cleanup_glue_dir

write to 0xffff88821b1e6340 of 8 bytes by task 28535 on cpu 1:
 kernfs_unlink_sibling fs/kernfs/dir.c:396 [inline]
 __kernfs_remove+0x592/0x6a0 fs/kernfs/dir.c:1331
 kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1357
 sysfs_remove_dir+0x7a/0x90 fs/sysfs/dir.c:102
 __kobject_del+0xac/0x100 lib/kobject.c:623
 kobject_del+0x20/0x30 lib/kobject.c:642
 device_del+0x9e7/0xa40 drivers/base/core.c:3119
 device_unregister drivers/base/core.c:3139 [inline]
 device_destroy+0x63/0xa0 drivers/base/core.c:3685
 tty_unregister_device+0x4e/0xd0 drivers/tty/tty_io.c:3190
 gsmld_detach_gsm drivers/tty/n_gsm.c:2411 [inline]
 gsmld_close+0x6c/0x140 drivers/tty/n_gsm.c:2480
 tty_ldisc_close drivers/tty/tty_ldisc.c:489 [inline]
 tty_ldisc_kill drivers/tty/tty_ldisc.c:637 [inline]
 tty_ldisc_hangup+0x363/0x4a0 drivers/tty/tty_ldisc.c:756
 __tty_hangup+0x464/0x610 drivers/tty/tty_io.c:625
 tty_vhangup drivers/tty/tty_io.c:698 [inline]
 tty_ioctl+0x5a1/0xfd0 drivers/tty/tty_io.c:2597
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88821b1e6340 of 8 bytes by task 28408 on cpu 0:
 kobject_has_children include/linux/kobject.h:135 [inline]
 cleanup_glue_dir+0xce/0x140 drivers/base/core.c:2629
 device_del+0x9f2/0xa40 drivers/base/core.c:3120
 device_unregister drivers/base/core.c:3139 [inline]
 device_destroy+0x63/0xa0 drivers/base/core.c:3685
 tty_unregister_device+0x4e/0xd0 drivers/tty/tty_io.c:3190
 gsmld_detach_gsm drivers/tty/n_gsm.c:2411 [inline]
 gsmld_close+0x6c/0x140 drivers/tty/n_gsm.c:2480
 tty_ldisc_close drivers/tty/tty_ldisc.c:489 [inline]
 tty_ldisc_kill drivers/tty/tty_ldisc.c:637 [inline]
 tty_ldisc_hangup+0x363/0x4a0 drivers/tty/tty_ldisc.c:756
 __tty_hangup+0x464/0x610 drivers/tty/tty_io.c:625
 tty_vhangup drivers/tty/tty_io.c:698 [inline]
 tty_ioctl+0x5a1/0xfd0 drivers/tty/tty_io.c:2597
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28408 Comm: syz-executor.2 Not tainted 5.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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