------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 5910 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 5910 Comm: kworker/0:4 Not tainted 6.12.0-syzkaller-09567-g7eef7e306d3c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events_long defense_work_handler RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Code: e0 05 61 8c e8 b7 17 96 fc 90 0f 0b 90 90 eb 99 e8 ab 6e d5 fc c6 05 e9 08 48 0b 01 90 48 c7 c7 40 06 61 8c e8 97 17 96 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 88 6e d5 fc c6 05 c3 08 48 0b 01 90 RSP: 0018:ffffc900000076e0 EFLAGS: 00010246 RAX: b72a217708ab5d00 RBX: ffff888034f34724 RCX: ffff888031673c00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: ffffffff815688b2 R09: 1ffff110170c519a R10: dffffc0000000000 R11: ffffed10170c519b R12: ffff888058117c00 R13: ffff888034f34724 R14: ffff888058117c00 R15: ffff88807a8d8918 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2711d0 CR3: 0000000078f28000 CR4: 0000000000350ef0 Call Trace: 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+0x2c7/0x980 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 local_bh_enable include/linux/bottom_half.h:33 [inline] update_defense_level+0x8ec/0xcf0 net/netfilter/ipvs/ip_vs_ctl.c:210 defense_work_handler+0x22/0xd0 net/netfilter/ipvs/ip_vs_ctl.c:235 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244