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BUG: KCSAN: data-race in del_timer / detach_if_pending

read to 0xffff888120dca9a0 of 8 bytes by task 19255 on cpu 0:
 del_timer+0x3b/0xb0 kernel/time/timer.c:1198
 sk_stop_timer+0x25/0x60 net/core/sock.c:2849
 tipc_release+0x1c4/0x980 net/tipc/socket.c:586
 __sock_release+0x12b/0x160 net/socket.c:590
 sock_release+0x21/0x30 net/socket.c:610
 tipc_conn_kref_release net/tipc/topsrv.c:135 [inline]
 kref_put include/linux/kref.h:65 [inline]
 conn_put+0xed/0x260 net/tipc/topsrv.c:148
 tipc_conn_recv_work+0x55/0x80 net/tipc/topsrv.c:427
 process_one_work+0x3d4/0x890 kernel/workqueue.c:2269
 worker_thread+0xa0/0x800 kernel/workqueue.c:2415
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

write to 0xffff888120dca9a0 of 8 bytes by task 20805 on cpu 1:
 __hlist_del include/linux/list.h:764 [inline]
 detach_timer kernel/time/timer.c:815 [inline]
 detach_if_pending+0xcd/0x290 kernel/time/timer.c:832
 del_timer kernel/time/timer.c:1200 [inline]
 del_timer+0x67/0xb0 kernel/time/timer.c:1190
 sk_stop_timer+0x25/0x60 net/core/sock.c:2849
 tipc_release+0x1c4/0x980 net/tipc/socket.c:586
 __sock_release+0x85/0x160 net/socket.c:590
 sock_close+0x24/0x30 net/socket.c:1268
 __fput+0x1e1/0x520 fs/file_table.c:280
 ____fput+0x1f/0x30 fs/file_table.c:313
 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:163
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x353/0x370 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 20805 Comm: syz-executor.4 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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