------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28, CPU#1: kworker/1:7/12772
Modules linked in:
CPU: 1 UID: 0 PID: 12772 Comm: kworker/1:7 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: rcu_gp process_srcu
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: 54 18 a6 0b 67 48 0f b9 3a eb 4a e8 78 0e 0d fd 48 8d 3d 51 18 a6 0b 67 48 0f b9 3a eb 37 e8 65 0e 0d fd 48 8d 3d 4e 18 a6 0b <67> 48 0f b9 3a eb 24 e8 52 0e 0d fd 48 8d 3d 4b 18 a6 0b 67 48 0f
RSP: 0018:ffffc90000a08c68 EFLAGS: 00010246
RAX: ffffffff84b95d8b RBX: 0000000000000003 RCX: ffff88802e851e80
RDX: 0000000000000100 RSI: ffffffff8f326380 RDI: ffffffff905f75e0
RBP: ffffc90000a08d70 R08: ffff88802e851e80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: 0000000000000001
R13: 000000010001f4b0 R14: ffff88804c77b820 R15: ffff88804c77b9b8
FS:  0000000000000000(0000) GS:ffff8881250e8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2be1de CR3: 000000009f7d0000 CR4: 00000000003526f0
DR0: fffffffffffffffd DR1: 0000020000000001 DR2: 0000000000000008
DR3: 0000000000000017 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:queue_delayed_work_on+0x17a/0x1e0 kernel/workqueue.c:2581
Code: 00 4d 85 f6 75 16 e8 05 3f 38 00 eb 15 e8 fe 3e 38 00 e8 59 47 2f 0a 4d 85 f6 74 ea e8 ef 3e 38 00 fb 65 48 8b 05 16 53 d5 11 <48> 3b 44 24 20 75 56 89 d8 48 83 c4 28 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc9000d9ffa80 EFLAGS: 00000293
RAX: ad6cbf1b240da100 RBX: ffff88803418aa01 RCX: ffff88802e851e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000008 R08: ffffffff905499f7 R09: 1ffffffff20a933e
R10: dffffc0000000000 R11: fffffbfff20a933f R12: 0000000001800001
R13: 0000000000000000 R14: 0000000000000200 R15: 0000000000000000
 process_one_work kernel/workqueue.c:3278 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3361
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3442
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	a6                   	cmpsb  %es:(%rdi),%ds:(%rsi)
   1:	0b 67 48             	or     0x48(%rdi),%esp
   4:	0f b9 3a             	ud1    (%rdx),%edi
   7:	eb 4a                	jmp    0x53
   9:	e8 78 0e 0d fd       	call   0xfd0d0e86
   e:	48 8d 3d 51 18 a6 0b 	lea    0xba61851(%rip),%rdi        # 0xba61866
  15:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1a:	eb 37                	jmp    0x53
  1c:	e8 65 0e 0d fd       	call   0xfd0d0e86
  21:	48 8d 3d 4e 18 a6 0b 	lea    0xba6184e(%rip),%rdi        # 0xba61876
* 28:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2d:	eb 24                	jmp    0x53
  2f:	e8 52 0e 0d fd       	call   0xfd0d0e86
  34:	48 8d 3d 4b 18 a6 0b 	lea    0xba6184b(%rip),%rdi        # 0xba61886
  3b:	67                   	addr32
  3c:	48                   	rex.W
  3d:	0f                   	.byte 0xf