------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 3319 at lib/refcount.c:28 refcount_warn_saturate+0xad/0x130 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 3319 Comm: syz.0.15 Not tainted 6.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:refcount_warn_saturate+0xad/0x130 lib/refcount.c:28
Code: 59 ff 90 0f 0b 90 90 c3 cc cc cc cc 80 3d b1 cb 3f 02 00 75 97 c6 05 a8 cb 3f 02 01 90 48 c7 c7 a0 1a 91 83 e8 04 08 59 ff 90 <0f> 0b 90 90 c3 cc cc cc cc 80 3d 87 cb 3f 02 00 0f 85 6c ff ff ff
RSP: 0018:ffffc900000e8cd0 EFLAGS: 00010246
RAX: 3d54262b5fa0aa00 RBX: ffff8881053fcf00 RCX: 0000000000000103
RDX: 0000000000000002 RSI: 00000000ffffdfff RDI: 00000000ffffffff
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff83cd0040
R10: ffffc900000e8ba8 R11: ffffc900000e8b50 R12: ffff888106702a10
R13: 0000000000000000 R14: ffff888109b71c00 R15: ffff888109b71c68
FS:  00007f00977af6c0(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3545a81440 CR3: 00000001053b2000 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_destroy net/can/j1939/transport.c:282 [inline]
 __j1939_session_release net/can/j1939/transport.c:294 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put+0xa5/0x190 net/can/j1939/transport.c:299
 j1939_tp_cmd_recv net/can/j1939/transport.c:2113 [inline]
 j1939_tp_recv+0x2c9/0x4b0 net/can/j1939/transport.c:2161
 j1939_can_recv+0x1e4/0x290 net/can/j1939/main.c:108
 deliver net/can/af_can.c:572 [inline]
 can_rcv_filter+0x80/0x190 net/can/af_can.c:606
 can_receive+0xca/0x110 net/can/af_can.c:663
 can_rcv+0x4b/0x90 net/can/af_can.c:687
 __netif_receive_skb_one_core net/core/dev.c:5660 [inline]
 __netif_receive_skb+0xa8/0x160 net/core/dev.c:5774
 process_backlog+0x203/0x520 net/core/dev.c:6107
 __napi_poll+0x28/0x160 net/core/dev.c:6771
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0x275/0x480 net/core/dev.c:6962
 handle_softirqs+0x118/0x390 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0x45/0xc0 kernel/softirq.c:637
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x92/0xb0 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x59/0xb0 kernel/locking/spinlock.c:194
Code: df e8 9b d7 48 fe 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 3b 41 f7 c6 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 32 3b 45 fe 65 8b 05 e3 03 2f 7d 85 c0 74 2c 65 48 8b 04 25 28
RSP: 0018:ffffc900036cbbf8 EFLAGS: 00000206
RAX: 0000000000000001 RBX: ffff888237d20440 RCX: 0000000000000001
RDX: ffffffff83c72e30 RSI: ffffffff838588bc RDI: 0000000000000001
RBP: ffff888106b6c800 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff810700a0 R12: ffffc900036cbd50
R13: 0000000000000009 R14: 0000000000000282 R15: 0000000000000009
 j1939_sk_send_loop net/can/j1939/socket.c:1164 [inline]
 j1939_sk_sendmsg+0x425/0x570 net/can/j1939/socket.c:1277
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x8e/0xb0 net/socket.c:745
 ____sys_sendmsg+0x1a7/0x200 net/socket.c:2597
 ___sys_sendmsg net/socket.c:2651 [inline]
 __sys_sendmsg+0x2c7/0x310 net/socket.c:2680
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xe0/0x220 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f00969773b9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f00977af048 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0096b05f80 RCX: 00007f00969773b9
RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000003
RBP: 00007f00969e48e6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000006 R14: 00007f0096b05f80 R15: 00007fffbad957f8
 </TASK>
----------------
Code disassembly (best guess):
   0:	df e8                	fucomip %st(0),%st
   2:	9b                   	fwait
   3:	d7                   	xlat   %ds:(%rbx)
   4:	48 fe 48 c7          	rex.W decb -0x39(%rax)
   8:	04 24                	add    $0x24,%al
   a:	00 00                	add    %al,(%rax)
   c:	00 00                	add    %al,(%rax)
   e:	9c                   	pushf
   f:	8f 04 24             	pop    (%rsp)
  12:	f7 04 24 00 02 00 00 	testl  $0x200,(%rsp)
  19:	75 3b                	jne    0x56
  1b:	41 f7 c6 00 02 00 00 	test   $0x200,%r14d
  22:	74 01                	je     0x25
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
* 2a:	e8 32 3b 45 fe       	call   0xfe453b61 <-- trapping instruction
  2f:	65 8b 05 e3 03 2f 7d 	mov    %gs:0x7d2f03e3(%rip),%eax        # 0x7d2f0419
  36:	85 c0                	test   %eax,%eax
  38:	74 2c                	je     0x66
  3a:	65                   	gs
  3b:	48                   	rex.W
  3c:	8b                   	.byte 0x8b
  3d:	04 25                	add    $0x25,%al
  3f:	28                   	.byte 0x28