------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 58 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Modules linked in: CPU: 1 UID: 0 PID: 58 Comm: kworker/1:2 Not tainted 6.13.0-rc1-syzkaller-00025-gfeffde684ac2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: mld mld_ifc_work RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Code: e0 1e 5f 8c e8 87 c5 95 fc 90 0f 0b 90 90 eb 99 e8 2b 1e d5 fc c6 05 6d 2c 39 0b 01 90 48 c7 c7 40 1f 5f 8c e8 67 c5 95 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 08 1e d5 fc c6 05 47 2c 39 0b 01 90 RSP: 0018:ffffc90000a186c0 EFLAGS: 00010246 RAX: 84e38118e7fe1600 RBX: ffff888030fca0e4 RCX: ffff888022ab1e00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: ffffffff81601c02 R09: fffffbfff1cfa210 R10: dffffc0000000000 R11: fffffbfff1cfa210 R12: ffff888028057800 R13: ffff888030fca0e4 R14: ffff888028057800 R15: ffff888033647618 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000f50b5da4 CR3: 0000000032a8e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 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+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+0x2d4/0x9b0 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 ipv6_get_lladdr+0x295/0x3d0 net/ipv6/addrconf.c:1936 mld_newpack+0x337/0xaf0 net/ipv6/mcast.c:1755 add_grhead net/ipv6/mcast.c:1850 [inline] add_grec+0x1492/0x19a0 net/ipv6/mcast.c:1988 mld_send_cr net/ipv6/mcast.c:2114 [inline] mld_ifc_work+0x691/0xd90 net/ipv6/mcast.c:2651 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244