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sched: Unexpected reschedule of offline CPU#3!
WARNING: arch/x86/kernel/apic/ipi.c:71 at native_smp_send_reschedule+0x4d/0x60 arch/x86/kernel/apic/ipi.c:71, CPU#2: kworker/u32:4/5842
Modules linked in:
CPU: 2 UID: 0 PID: 5842 Comm: kworker/u32:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:native_smp_send_reschedule+0x4f/0x60 arch/x86/kernel/apic/ipi.c:71
Code: b0 c6 00 48 0f a3 2d a8 86 8e 0f 73 14 89 df be fd 00 00 00 5b 5d e9 a0 2a 01 00 90 0f 0b 90 eb c7 48 8d 3d 63 3f 91 0f 89 de <67> 48 0f b9 3a 5b 5d e9 05 b6 19 0a 0f 1f 44 00 00 90 90 90 90 90
RSP: 0018:ffffc9000617ee40 EFLAGS: 00010046
RAX: 0000000000000001 RBX: 0000000000000003 RCX: ffffffff81b69fa8
RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffffffff9147df30
RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff228a4cb
R10: ffffffff9145265f R11: 0000000000000003 R12: 0000000000000004
R13: 1ffff92000c2fdcc R14: ffffc9000617ee80 R15: 0000000000000010
FS:  0000000000000000(0000) GS:ffff888096b67000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a33142b090 CR3: 000000000eb96000 CR4: 0000000000350ef0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_smp_send_reschedule arch/x86/include/asm/smp.h:90 [inline]
 __resched_curr+0x2db/0x500 kernel/sched/core.c:1225
 wakeup_preempt+0xd0/0x400 kernel/sched/core.c:2301
 ttwu_do_activate+0x1ad/0x800 kernel/sched/core.c:3835
 ttwu_queue kernel/sched/core.c:4087 [inline]
 try_to_wake_up+0xcf0/0x1c90 kernel/sched/core.c:4425
 cpu_stop_queue_work+0x271/0x340 kernel/stop_machine.c:108
 stop_one_cpu_nowait+0xe8/0x160 kernel/stop_machine.c:387
 sched_balance_rq+0x317c/0x48b0 kernel/sched/fair.c:13661
 sched_balance_newidle kernel/sched/fair.c:14627 [inline]
 pick_task_fair+0xb6b/0x1e00 kernel/sched/fair.c:10073
 __pick_next_task+0x105/0x710 kernel/sched/core.c:6159
 pick_next_task kernel/sched/core.c:6257 [inline]
 __schedule+0x57f/0x6920 kernel/sched/core.c:7185
 __schedule_loop kernel/sched/core.c:7347 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7362
 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121
 kthread_stop+0x18e/0x630 kernel/kthread.c:760
 rxrpc_unuse_local+0x107/0x140 net/rxrpc/local_object.c:409
 rxrpc_release_sock net/rxrpc/af_rxrpc.c:967 [inline]
 rxrpc_release+0x384/0x6a0 net/rxrpc/af_rxrpc.c:994
 __sock_release net/socket.c:735 [inline]
 sock_release+0x91/0x1c0 net/socket.c:763
 afs_close_socket+0x24b/0x410 fs/afs/rxrpc.c:154
 afs_net_exit+0x93/0x150 fs/afs/main.c:149
 ops_exit_list net/core/net_namespace.c:200 [inline]
 ops_undo_list+0x2ee/0xab0 net/core/net_namespace.c:253
 cleanup_net+0x499/0x920 net/core/net_namespace.c:706
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
 process_scheduled_works kernel/workqueue.c:3470 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	b0 c6                	mov    $0xc6,%al
   2:	00 48 0f             	add    %cl,0xf(%rax)
   5:	a3 2d a8 86 8e 0f 73 	movabs %eax,0x8914730f8e86a82d
   c:	14 89
   e:	df be fd 00 00 00    	fistpll 0xfd(%rsi)
  14:	5b                   	pop    %rbx
  15:	5d                   	pop    %rbp
  16:	e9 a0 2a 01 00       	jmp    0x12abb
  1b:	90                   	nop
  1c:	0f 0b                	ud2
  1e:	90                   	nop
  1f:	eb c7                	jmp    0xffffffe8
  21:	48 8d 3d 63 3f 91 0f 	lea    0xf913f63(%rip),%rdi        # 0xf913f8b
  28:	89 de                	mov    %ebx,%esi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	5b                   	pop    %rbx
  30:	5d                   	pop    %rbp
  31:	e9 05 b6 19 0a       	jmp    0xa19b63b
  36:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop