------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 5241 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 5241 Comm: kworker/0:3 Not tainted 6.11.0-rc6-syzkaller-01330-gbf73478b539b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: events nsim_fib_event_work
RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Code: 00 3b 60 8c e8 b7 2d a3 fc 90 0f 0b 90 90 eb 99 e8 7b 09 e1 fc c6 05 75 d4 4f 0b 01 90 48 c7 c7 60 3b 60 8c e8 97 2d a3 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 58 09 e1 fc c6 05 4f d4 4f 0b 01 90
RSP: 0018:ffffc90000007640 EFLAGS: 00010246
RAX: 92b8b6f44ed2d900 RBX: ffff888028e6d5e4 RCX: ffff88801fff3c00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff8155b372 R09: 1ffff1101710519a
R10: dffffc0000000000 R11: ffffed101710519b R12: ffff888022fa1c00
R13: ffff888028e6d5e4 R14: ffff888022fa1c00 R15: ffff88807c563018
FS:  0000000000000000(0000) GS:ffff8880b8800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020015000 CR3: 000000007d230000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 kfree_skb_reason include/linux/skbuff.h:1260 [inline]
 kfree_skb include/linux/skbuff.h:1269 [inline]
 j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline]
 j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline]
 j1939_xtp_rx_cts+0x552/0xc70 net/can/j1939/transport.c:1484
 j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline]
 j1939_tp_recv+0x8ae/0x1050 net/can/j1939/transport.c:2161
 j1939_can_recv+0x732/0xb20 net/can/j1939/main.c:108
 deliver net/can/af_can.c:572 [inline]
 can_rcv_filter+0x359/0x7f0 net/can/af_can.c:606
 can_receive+0x31c/0x470 net/can/af_can.c:663
 can_rcv+0x144/0x260 net/can/af_can.c:687
 __netif_receive_skb_one_core net/core/dev.c:5656 [inline]
 __netif_receive_skb+0x2e0/0x650 net/core/dev.c:5769
 process_backlog+0x662/0x15b0 net/core/dev.c:6101
 __napi_poll+0xcb/0x490 net/core/dev.c:6765
 napi_poll net/core/dev.c:6834 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:6956
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5062
Code: c9 50 e8 d9 b6 0b 00 48 83 c4 08 4c 89 f7 e8 7d 38 00 00 0f 1f 44 00 00 4c 89 f7 e8 10 73 60 0a e8 bb db 36 00 fb 48 8b 5d c0 <48> 8d bb f8 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc
RSP: 0018:ffffc90003a8f308 EFLAGS: 00000286
RAX: 92b8b6f44ed2d900 RBX: ffff88801fff3c00 RCX: ffffffff81703fea
RDX: dffffc0000000000 RSI: ffffffff8c0ad560 RDI: ffffffff8c608d80
RBP: ffffc90003a8f350 R08: ffffffff941e7927 R09: 1ffffffff283cf24
R10: dffffc0000000000 R11: fffffbfff283cf25 R12: 1ffff11017107e9b
R13: dffffc0000000000 R14: ffff8880b883e740 R15: ffff8880b883f4d8
 context_switch kernel/sched/core.c:5191 [inline]
 __schedule+0x1808/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581
 schedule_timeout_uninterruptible kernel/time/timer.c:2615 [inline]
 msleep+0xa2/0xe0 kernel/time/timer.c:2736
 nsim_fib6_rt_add drivers/net/netdevsim/fib.c:693 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:759 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x2e2f/0x4130 drivers/net/netdevsim/fib.c:1492
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd10 kernel/workqueue.c:3389
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
----------------
Code disassembly (best guess):
   0:	c9                   	leave
   1:	50                   	push   %rax
   2:	e8 d9 b6 0b 00       	call   0xbb6e0
   7:	48 83 c4 08          	add    $0x8,%rsp
   b:	4c 89 f7             	mov    %r14,%rdi
   e:	e8 7d 38 00 00       	call   0x3890
  13:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  18:	4c 89 f7             	mov    %r14,%rdi
  1b:	e8 10 73 60 0a       	call   0xa607330
  20:	e8 bb db 36 00       	call   0x36dbe0
  25:	fb                   	sti
  26:	48 8b 5d c0          	mov    -0x40(%rbp),%rbx
* 2a:	48 8d bb f8 15 00 00 	lea    0x15f8(%rbx),%rdi <-- trapping instruction
  31:	48 89 f8             	mov    %rdi,%rax
  34:	48 c1 e8 03          	shr    $0x3,%rax
  38:	49                   	rex.WB
  39:	be 00 00 00 00       	mov    $0x0,%esi
  3e:	00 fc                	add    %bh,%ah