------------[ cut here ]------------ WARNING: CPU: 0 PID: 2968 at lib/refcount.c:28 refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28 refcount_t: underflow; use-after-free. Modules linked in: Kernel panic - not syncing: kernel: panic_on_warn set ... CPU: 0 UID: 0 PID: 2968 Comm: kworker/u8:2 Not tainted 6.11.0-syzkaller #0 Hardware name: ARM-Versatile Express Workqueue: ipv6_addrconf addrconf_dad_work Call trace: frame pointer underflow [<8197d658>] (dump_backtrace) from [<8197d754>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257) r7:00000000 r6:826228c4 r5:00000000 r4:82034f2c [<8197d73c>] (show_stack) from [<8199b3f8>] (__dump_stack lib/dump_stack.c:93 [inline]) [<8197d73c>] (show_stack) from [<8199b3f8>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:119) [<8199b3a4>] (dump_stack_lvl) from [<8199b438>] (dump_stack+0x18/0x1c lib/dump_stack.c:128) r5:00000000 r4:8286ed18 [<8199b420>] (dump_stack) from [<8197e1fc>] (panic+0x120/0x368 kernel/panic.c:354) [<8197e0dc>] (panic) from [<802421d4>] (check_panic_on_warn kernel/panic.c:243 [inline]) [<8197e0dc>] (panic) from [<802421d4>] (get_taint+0x0/0x1c kernel/panic.c:238) r3:8260c5c4 r2:00000001 r1:8201d760 r0:8202552c r7:808309e0 [<80242160>] (check_panic_on_warn) from [<80242328>] (__warn+0x7c/0x180 kernel/panic.c:741) [<802422ac>] (__warn) from [<80242614>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:774) r8:00000009 r7:82083a1c r6:df801c94 r5:83720000 r4:00000000 [<80242430>] (warn_slowpath_fmt) from [<808309e0>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28) r10:20000113 r9:84d7985c r8:84ddbd80 r7:00000000 r6:8180dd24 r5:00000002 r4:84ddbd80 [<808308a4>] (refcount_warn_saturate) from [<8147e1bc>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline]) [<808308a4>] (refcount_warn_saturate) from [<8147e1bc>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline]) [<808308a4>] (refcount_warn_saturate) from [<8147e1bc>] (refcount_dec_and_test include/linux/refcount.h:325 [inline]) [<808308a4>] (refcount_warn_saturate) from [<8147e1bc>] (skb_unref include/linux/skbuff.h:1232 [inline]) [<808308a4>] (refcount_warn_saturate) from [<8147e1bc>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline]) [<808308a4>] (refcount_warn_saturate) from [<8147e1bc>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241) [<8147dfe4>] (sk_skb_reason_drop) from [<8180dd24>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline]) [<8147dfe4>] (sk_skb_reason_drop) from [<8180dd24>] (kfree_skb include/linux/skbuff.h:1271 [inline]) [<8147dfe4>] (sk_skb_reason_drop) from [<8180dd24>] (j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline]) [<8147dfe4>] (sk_skb_reason_drop) from [<8180dd24>] (j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline]) [<8147dfe4>] (sk_skb_reason_drop) from [<8180dd24>] (j1939_xtp_rx_cts+0x220/0x3d0 net/can/j1939/transport.c:1484) r9:84d7985c r8:84ddbd80 r7:8554e918 r6:00000df2 r5:84d79800 r4:84d79814 [<8180db04>] (j1939_xtp_rx_cts) from [<8180ec98>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline]) [<8180db04>] (j1939_xtp_rx_cts) from [<8180ec98>] (j1939_tp_recv+0x3f4/0x530 net/can/j1939/transport.c:2161) r10:dddd0ec8 r9:00000040 r8:8554e910 r7:84743000 r6:84743008 r5:84743000 r4:85647240 [<8180e8a4>] (j1939_tp_recv) from [<81808730>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108) r7:84743000 r6:84743008 r5:84743810 r4:85647240 [<8180854c>] (j1939_can_recv) from [<817fe4fc>] (deliver net/can/af_can.c:572 [inline]) [<8180854c>] (j1939_can_recv) from [<817fe4fc>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606) r9:00000040 r8:84f0c6a0 r7:98c80000 r6:85647180 r5:00000001 r4:853e45a0 [<817fe460>] (can_rcv_filter) from [<817feea0>] (can_receive+0xb4/0xf0 net/can/af_can.c:663) r9:00000040 r8:00000000 r7:84f0c000 r6:85099cc0 r5:84640d00 r4:85647180 [<817fedec>] (can_receive) from [<817fef60>] (can_rcv+0x84/0xac net/can/af_can.c:687) r9:00000040 r8:00000002 r7:00000000 r6:00000000 r5:817feedc r4:85647180 [<817feedc>] (can_rcv) from [<8149f034>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5662) r5:817feedc r4:84f0c000 [<8149efd8>] (__netif_receive_skb_one_core) from [<8149f0a0>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5775) r5:dddd0fb0 r4:85647180 [<8149f088>] (__netif_receive_skb) from [<8149f390>] (process_backlog+0x88/0x15c net/core/dev.c:6107) r5:dddd0fb0 r4:85647180 [<8149f308>] (process_backlog) from [<814a0294>] (__napi_poll+0x34/0x240 net/core/dev.c:6771) r10:dddd0ec0 r9:dddd1100 r8:df801ed0 r7:df801ecb r6:00000040 r5:dddd0fb0 r4:00000001 [<814a0260>] (__napi_poll) from [<814a0acc>] (napi_poll net/core/dev.c:6840 [inline]) [<814a0260>] (__napi_poll) from [<814a0acc>] (net_rx_action+0x338/0x420 net/core/dev.c:6962) r9:dddd1100 r8:df801ed0 r7:0000012c r6:00000a5e r5:dddd0fb0 r4:00000000 [<814a0794>] (net_rx_action) from [<8024b5d8>] (handle_softirqs+0x15c/0x468 kernel/softirq.c:554) r10:00000008 r9:83720000 r8:00000101 r7:04208060 r6:00000003 r5:00000004 r4:8260408c [<8024b47c>] (handle_softirqs) from [<802012d0>] (__do_softirq+0x14/0x18 kernel/softirq.c:588) r10:842c1680 r9:84d04084 r8:dddd1184 r7:84d04048 r6:84d04b88 r5:00000001 r4:60000113 [<802012bc>] (__do_softirq) from [<80208800>] (____do_softirq+0x10/0x14 arch/arm/kernel/irq.c:77) [<802087f0>] (____do_softirq) from [<8194d0f8>] (call_with_stack+0x1c/0x20 arch/arm/lib/call_with_stack.S:40) [<8194d0dc>] (call_with_stack) from [<8020883c>] (do_softirq_own_stack+0x38/0x3c arch/arm/kernel/irq.c:82) [<80208804>] (do_softirq_own_stack) from [<8024baf0>] (do_softirq kernel/softirq.c:455 [inline]) [<80208804>] (do_softirq_own_stack) from [<8024baf0>] (do_softirq+0x5c/0x64 kernel/softirq.c:442) [<8024ba94>] (do_softirq) from [<8024bbc4>] (__local_bh_enable_ip+0xcc/0xd0 kernel/softirq.c:382) r5:00000001 r4:83720000 [<8024baf8>] (__local_bh_enable_ip) from [<819a8418>] (__raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]) [<8024baf8>] (__local_bh_enable_ip) from [<819a8418>] (_raw_spin_unlock_bh+0x34/0x38 kernel/locking/spinlock.c:210) r5:84d04000 r4:dddd1180 [<819a83e4>] (_raw_spin_unlock_bh) from [<817509b8>] (spin_unlock_bh include/linux/spinlock.h:396 [inline]) [<819a83e4>] (_raw_spin_unlock_bh) from [<817509b8>] (rt6_uncached_list_add+0x64/0x68 net/ipv6/route.c:146) [<81750954>] (rt6_uncached_list_add) from [<817530ec>] (icmp6_dst_alloc+0xf4/0x1ac net/ipv6/route.c:3293) r9:84d04084 r8:84f10d00 r7:846dd400 r6:ec1d5db0 r5:00000080 r4:84d04000 [<81752ff8>] (icmp6_dst_alloc) from [<8175f124>] (ndisc_send_skb+0x3a0/0x428 net/ipv6/ndisc.c:491) r9:0000b470 r8:896550a9 r7:84f10d00 r6:8554ebd8 r5:00000000 r4:856470c0 [<8175ed84>] (ndisc_send_skb) from [<817603d0>] (ndisc_send_ns+0x70/0xb0 net/ipv6/ndisc.c:669) r10:837dd805 r9:0000b470 r8:896550a9 r7:84ecf800 r6:ec1d5e98 r5:84dd4600 r4:81c6f0d0 [<81760360>] (ndisc_send_ns) from [<81744b2c>] (addrconf_dad_work+0x39c/0x570 net/ipv6/addrconf.c:4284) r9:846dd548 r8:84dd4600 r7:0000b470 r6:896550a9 r5:84dd4648 r4:84dd4620 [<81744790>] (addrconf_dad_work) from [<80265ef4>] (process_one_work+0x1b4/0x4f4 kernel/workqueue.c:3231) r10:837dd805 r9:83720000 r8:02000000 r7:82c0e600 r6:837dd800 r5:84dd4648 r4:8420eb00 [<80265d40>] (process_one_work) from [<80266ad8>] (process_scheduled_works kernel/workqueue.c:3312 [inline]) [<80265d40>] (process_one_work) from [<80266ad8>] (worker_thread+0x1ec/0x3bc kernel/workqueue.c:3393) r10:83720000 r9:8420eb2c r8:61c88647 r7:82c0e620 r6:82604d40 r5:82c0e600 r4:8420eb00 [<802668ec>] (worker_thread) from [<8026faf4>] (kthread+0x104/0x134 kernel/kthread.c:389) r10:00000000 r9:e86d5e78 r8:846fc240 r7:8420eb00 r6:802668ec r5:83720000 r4:846b0080 [<8026f9f0>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137) Exception stack(0xec1d5fb0 to 0xec1d5ff8) 5fa0: 00000000 00000000 00000000 00000000 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:8026f9f0 r4:846b0080 Rebooting in 86400 seconds..