------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 5818 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 5818 Comm: syz-executor Not tainted 6.12.0-next-20241125-syzkaller #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: 20 3e 5f 8c e8 b7 d0 93 fc 90 0f 0b 90 90 eb 99 e8 1b 32 d3 fc c6 05 76 85 37 0b 01 90 48 c7 c7 80 3e 5f 8c e8 97 d0 93 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 f8 31 d3 fc c6 05 50 85 37 0b 01 90
RSP: 0018:ffffc900000076e0 EFLAGS: 00010246
RAX: e4725d56b906df00 RBX: ffff8880279224a4 RCX: ffff88802bb08000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff81601b32 R09: fffffbfff1cfa218
R10: dffffc0000000000 R11: fffffbfff1cfa218 R12: ffff88804643c000
R13: ffff8880279224a4 R14: ffff88804643c000 R15: ffff888045e12d18
FS:  000055558166c500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2bd877 CR3: 0000000034196000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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+0x359/0x7f0 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+0x2e0/0x650 net/core/dev.c:5785
 process_backlog+0x662/0x15b0 net/core/dev.c:6117
 __napi_poll+0xcb/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+0x2c5/0x980 kernel/softirq.c:554
 do_softirq+0x11b/0x1e0 kernel/softirq.c:455
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
 __dev_queue_xmit+0x1775/0x3f50 net/core/dev.c:4461
 dev_queue_xmit include/linux/netdevice.h:3168 [inline]
 neigh_hh_output include/net/neighbour.h:523 [inline]
 neigh_output include/net/neighbour.h:537 [inline]
 ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236
 ip_local_out net/ipv4/ip_output.c:130 [inline]
 __ip_queue_xmit+0x12ca/0x1ef0 net/ipv4/ip_output.c:536
 __tcp_transmit_skb+0x2582/0x3ba0 net/ipv4/tcp_output.c:1466
 tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline]
 tcp_write_xmit+0x17b5/0x6bf0 net/ipv4/tcp_output.c:2827
 __tcp_push_pending_frames+0x9b/0x360 net/ipv4/tcp_output.c:3010
 tcp_sendmsg_locked+0x44d6/0x4f30 net/ipv4/tcp.c:1326
 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1358
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x1a6/0x270 net/socket.c:726
 sock_write_iter+0x2d7/0x3f0 net/socket.c:1147
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0xaeb/0xd30 fs/read_write.c:679
 ksys_write+0x18f/0x2b0 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff02597d2c0
Code: 40 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 80 3d 81 02 19 00 00 74 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83 ec 28 48 89
RSP: 002b:00007ffc2b587058 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000a21fe80 RCX: 00007ff02597d2c0
RDX: 0000000000000fc0 RSI: 00007ff01f3ff040 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000007 R09: 00000000003ffdf0
R10: 8df53aa773c12200 R11: 0000000000000202 R12: 0000000000000fc0
R13: 0000555581680c70 R14: 00007ffc2b587520 R15: 00007ff01f3ff040
 </TASK>