------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 16 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-rc4-syzkaller-00047-gc2ee9f594da8 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 d8 7f fd fc 84 db 0f 85 66 ff ff ff e8 eb 7d fd fc c6 05 29 0c b8 0b 01 90 48 c7 c7 80 57 d1 8b e8 e7 6e be fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 c8 7d fd fc 0f b6 1d 04 0c b8 0b 31
RSP: 0018:ffffc900001377e0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff814e71a9
RDX: ffff88801dab8000 RSI: ffffffff814e71b6 RDI: 0000000000000001
RBP: ffff88802cf9eea4 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: ffff88802cf9eea4 R15: ffff888039129b19
FS:  0000000000000000(0000) GS:ffff88806a600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020015000 CR3: 000000002ea44000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:275 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 skb_unref include/linux/skbuff.h:1232 [inline]
 __sk_skb_reason_drop net/core/skbuff.c:1213 [inline]
 sk_skb_reason_drop+0x183/0x1a0 net/core/skbuff.c:1241
 kfree_skb_reason include/linux/skbuff.h:1262 [inline]
 kfree_skb include/linux/skbuff.h:1271 [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+0x622/0xf50 net/can/j1939/transport.c:1484
 j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline]
 j1939_tp_recv+0x568/0xf50 net/can/j1939/transport.c:2161
 j1939_can_recv+0x78f/0xa50 net/can/j1939/main.c:108
 deliver net/can/af_can.c:572 [inline]
 can_rcv_filter+0x2a8/0x900 net/can/af_can.c:606
 can_receive+0x320/0x5c0 net/can/af_can.c:663
 can_rcv+0x1e2/0x280 net/can/af_can.c:687
 __netif_receive_skb_one_core+0x1b1/0x1e0 net/core/dev.c:5666
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5779
 process_backlog+0x443/0x15f0 net/core/dev.c:6111
 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6775
 napi_poll net/core/dev.c:6844 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6966
 handle_softirqs+0x213/0x8f0 kernel/softirq.c:554
 run_ksoftirqd kernel/softirq.c:927 [inline]
 run_ksoftirqd+0x3a/0x60 kernel/softirq.c:919
 smpboot_thread_fn+0x661/0xa30 kernel/smpboot.c:164
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>