------------[ cut here ]------------
WARNING: CPU: 1 PID: 4424 at kernel/workqueue.c:1441 __queue_work+0xe2d/0xfb0 kernel/workqueue.c:1441
Modules linked in:
CPU: 1 PID: 4424 Comm: kworker/1:11 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events free_ipc
RIP: 0010:__queue_work+0xe2d/0xfb0 kernel/workqueue.c:1441
Code: e9 9d fc ff ff 48 8b 0c 24 80 e1 07 80 c1 03 38 c1 0f 8c c7 fc ff ff 48 8b 3c 24 e8 5d 2e 7f 00 e9 b9 fc ff ff e8 a3 b5 2d 00 <0f> 0b 48 83 c4 60 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 8d b5 2d 00
RSP: 0018:ffffc900001e0ae8 EFLAGS: 00010046
RAX: ffffffff815320cd RBX: 0000000000010000 RCX: ffff88802a22bb80
RDX: 0000000000000100 RSI: 0000000000000100 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1bfd0b6
R10: fffffbfff1bfd0b6 R11: 1ffffffff1bfd0b5 R12: ffff888023b8b000
R13: ffff888023b8b1c0 R14: 0000000000000008 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa8710be4e8 CR3: 0000000079d2d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1544 [inline]
 __run_timers+0x550/0x7c0 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:queue_work_on+0x183/0x1d0 kernel/workqueue.c:1553
Code: 4d 85 e4 75 16 e8 3d c4 2d 00 eb 15 e8 36 c4 2d 00 e8 e1 7e bc 08 4d 85 e4 74 ea e8 27 c4 2d 00 fb 48 c7 44 24 20 0e 36 e0 45 <48> b8 00 00 00 00 00 fc ff df 49 c7 44 05 00 00 00 00 00 66 41 c7
RSP: 0018:ffffc900034a76c0 EFLAGS: 00000293
RAX: ffffffff81531249 RBX: 0000000000000000 RCX: ffff88802a22bb80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900034a7790 R08: dffffc0000000000 R09: fffffbfff211704b
R10: fffffbfff211704b R11: 1ffffffff211704a R12: 0000000000000200
R13: 1ffff92000694edc R14: 0000000000000000 R15: ffffc900034a7801
 queue_work include/linux/workqueue.h:512 [inline]
 synchronize_rcu_expedited_queue_work kernel/rcu/tree_exp.h:527 [inline]
 synchronize_rcu_expedited+0x59c/0x830 kernel/rcu/tree_exp.h:972
 synchronize_rcu+0x11c/0x380 kernel/rcu/tree.c:3576
 kern_unmount+0x66/0xf0 fs/namespace.c:4488
 free_ipc_ns ipc/namespace.c:138 [inline]
 free_ipc+0x69/0x1d0 ipc/namespace.c:159
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess):
   0:	4d 85 e4             	test   %r12,%r12
   3:	75 16                	jne    0x1b
   5:	e8 3d c4 2d 00       	call   0x2dc447
   a:	eb 15                	jmp    0x21
   c:	e8 36 c4 2d 00       	call   0x2dc447
  11:	e8 e1 7e bc 08       	call   0x8bc7ef7
  16:	4d 85 e4             	test   %r12,%r12
  19:	74 ea                	je     0x5
  1b:	e8 27 c4 2d 00       	call   0x2dc447
  20:	fb                   	sti
  21:	48 c7 44 24 20 0e 36 	movq   $0x45e0360e,0x20(%rsp)
  28:	e0 45
* 2a:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax <-- trapping instruction
  31:	fc ff df
  34:	49 c7 44 05 00 00 00 	movq   $0x0,0x0(%r13,%rax,1)
  3b:	00 00
  3d:	66                   	data16
  3e:	41                   	rex.B
  3f:	c7                   	.byte 0xc7