------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 7086 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 7086 Comm: syz.2.315 Not tainted 6.13.0-rc1-syzkaller-00005-gceb8bf2ceaa7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Code: e0 1e 5f 8c e8 07 c1 95 fc 90 0f 0b 90 90 eb 99 e8 ab 19 d5 fc c6 05 ed 27 39 0b 01 90 48 c7 c7 40 1f 5f 8c e8 e7 c0 95 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 88 19 d5 fc c6 05 c7 27 39 0b 01 90
RSP: 0018:ffffc90000a186c0 EFLAGS: 00010246
RAX: ad4f23b044127800 RBX: ffff88807afadc24 RCX: ffff888030518000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff81601c02 R09: 1ffff110170e519a
R10: dffffc0000000000 R11: ffffed10170e519b R12: ffff888022f78800
R13: ffff88807afadc24 R14: ffff888022f78800 R15: ffff888079708618
FS:  000055557578c500(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020015000 CR3: 000000007dc60000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 kfree_skb_reason include/linux/skbuff.h:1263 [inline]
 kfree_skb include/linux/skbuff.h:1272 [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:573 [inline]
 can_rcv_filter+0x35b/0x7f0 net/can/af_can.c:607
 can_receive+0x327/0x480 net/can/af_can.c:664
 can_rcv+0x144/0x260 net/can/af_can.c:688
 __netif_receive_skb_one_core net/core/dev.c:5672 [inline]
 __netif_receive_skb+0x2e2/0x650 net/core/dev.c:5785
 process_backlog+0x662/0x15b0 net/core/dev.c:6117
 __napi_poll+0xcd/0x490 net/core/dev.c:6877
 napi_poll net/core/dev.c:6946 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:7068
 handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:554
 do_softirq+0x11b/0x1e0 kernel/softirq.c:455
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 __tun_set_ebpf+0x124/0x1c0 drivers/net/tun.c:2307
 netdev_run_todo+0xe1c/0x1000 net/core/dev.c:10911
 tun_detach drivers/net/tun.c:704 [inline]
 tun_chr_close+0x137/0x1b0 drivers/net/tun.c:3517
 __fput+0x23e/0xa50 fs/file_table.c:450
 task_work_run+0x251/0x310 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f83e677ff19
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:00007ffe88cb98e8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f83e6947ba0 RCX: 00007f83e677ff19
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f83e6947ba0 R08: 00000000000000a0 R09: 00007ffe88cb9bcf
R10: 00007f83e6947ac0 R11: 0000000000000246 R12: 000000000002aba4
R13: 00007f83e6945fa0 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>