syzbot

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BUG: KCSAN: data-race in cleanup_glue_dir / kernfs_link_sibling

write to 0xffff8881305b0bc0 of 8 bytes by task 29206 on cpu 1:
 kernfs_link_sibling+0x21c/0x240 fs/kernfs/dir.c:374
 kernfs_add_one+0x280/0x3c0 fs/kernfs/dir.c:786
 kernfs_create_dir_ns+0xfc/0x140 fs/kernfs/dir.c:1035
 sysfs_create_dir_ns+0x94/0x190 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:89 [inline]
 kobject_add_internal+0x488/0x880 lib/kobject.c:255
 kobject_add_varg lib/kobject.c:390 [inline]
 kobject_add+0xbe/0x130 lib/kobject.c:442
 device_add+0x31d/0xf30 drivers/base/core.c:3257
 wakeup_source_device_create drivers/base/power/wakeup_stats.c:161 [inline]
 wakeup_source_sysfs_add+0x142/0x1b0 drivers/base/power/wakeup_stats.c:181
 wakeup_source_register+0xfd/0x250 drivers/base/power/wakeup.c:227
 ep_create_wakeup_source fs/eventpoll.c:1369 [inline]
 ep_insert fs/eventpoll.c:1495 [inline]
 do_epoll_ctl+0xedc/0x1860 fs/eventpoll.c:2133
 __do_sys_epoll_ctl fs/eventpoll.c:2184 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2175 [inline]
 __x64_sys_epoll_ctl+0xb3/0xe0 fs/eventpoll.c:2175
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881305b0bc0 of 8 bytes by task 29202 on cpu 0:
 kobject_has_children include/linux/kobject.h:135 [inline]
 cleanup_glue_dir+0xce/0x140 drivers/base/core.c:3023
 device_del+0x880/0x8f0 drivers/base/core.c:3525
 device_unregister+0x11/0x30 drivers/base/core.c:3545
 wakeup_source_sysfs_remove+0x21/0x30 drivers/base/power/wakeup_stats.c:208
 wakeup_source_unregister+0xea/0x110 drivers/base/power/wakeup.c:248
 ep_destroy_wakeup_source+0x3a/0x40 fs/eventpoll.c:1398
 ep_modify fs/eventpoll.c:1577 [inline]
 do_epoll_ctl+0x76b/0x1860 fs/eventpoll.c:2147
 __do_sys_epoll_ctl fs/eventpoll.c:2184 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2175 [inline]
 __x64_sys_epoll_ctl+0xb3/0xe0 fs/eventpoll.c:2175
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000037 -> 0x0000000000000038

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29202 Comm: syz-executor.2 Not tainted 5.13.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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