------------[ cut here ]------------
WARNING: CPU: 0 PID: 15 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: 15 Comm: ksoftirqd/0 Not tainted 6.12.0-rc6-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: 
[<8199c7f8>] (dump_backtrace) from [<8199c8f4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:82622f44 r5:00000000 r4:8203db14
[<8199c8dc>] (show_stack) from [<819bad88>] (__dump_stack lib/dump_stack.c:94 [inline])
[<8199c8dc>] (show_stack) from [<819bad88>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<819bad34>] (dump_stack_lvl) from [<819badc8>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82870d18
[<819badb0>] (dump_stack) from [<8199d420>] (panic+0x120/0x374 kernel/panic.c:354)
[<8199d300>] (panic) from [<80242118>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8199d300>] (panic) from [<80242118>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:82025ee8 r0:8202d950
 r7:80840670
[<802420a4>] (check_panic_on_warn) from [<8024227c>] (__warn+0x80/0x188 kernel/panic.c:748)
[<802421fc>] (__warn) from [<8024256c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783)
 r8:00000009 r7:8208c310 r6:df855bfc r5:82e3b000 r4:00000000
[<80242388>] (warn_slowpath_fmt) from [<80840670>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:20000013 r9:84fc195c r8:82fa4480 r7:00000000 r6:8182c424 r5:00000002
 r4:82fa4480
[<80840534>] (refcount_warn_saturate) from [<8149b980>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b980>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b980>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b980>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b980>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b980>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<8149b7a8>] (sk_skb_reason_drop) from [<8182c424>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<8149b7a8>] (sk_skb_reason_drop) from [<8182c424>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<8149b7a8>] (sk_skb_reason_drop) from [<8182c424>] (j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline])
[<8149b7a8>] (sk_skb_reason_drop) from [<8182c424>] (j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline])
[<8149b7a8>] (sk_skb_reason_drop) from [<8182c424>] (j1939_xtp_rx_cts+0x220/0x3d0 net/can/j1939/transport.c:1484)
 r9:84fc195c r8:82fa4480 r7:85131458 r6:00000df2 r5:84fc1900 r4:84fc1914
[<8182c204>] (j1939_xtp_rx_cts) from [<8182d398>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline])
[<8182c204>] (j1939_xtp_rx_cts) from [<8182d398>] (j1939_tp_recv+0x3f4/0x530 net/can/j1939/transport.c:2161)
 r10:dddd10c8 r9:00000040 r8:85131450 r7:83ff1000 r6:83ff1008 r5:83ff1000
 r4:82fbaa80
[<8182cfa4>] (j1939_tp_recv) from [<81826e30>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:83ff1000 r6:83ff1008 r5:83ff1810 r4:82fbaa80
[<81826c4c>] (j1939_can_recv) from [<8181cc00>] (deliver net/can/af_can.c:572 [inline])
[<81826c4c>] (j1939_can_recv) from [<8181cc00>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:84c98680 r7:98c80000 r6:82fba780 r5:00000001 r4:849a7ab0
[<8181cb64>] (can_rcv_filter) from [<8181d5a4>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:84c98000 r6:84f358c0 r5:852c3400 r4:82fba780
[<8181d4f0>] (can_receive) from [<8181d664>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000001 r7:00000000 r6:00000000 r5:8181d5e0 r4:82fba780
[<8181d5e0>] (can_rcv) from [<814bc8f4>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5670)
 r5:8181d5e0 r4:84c98000
[<814bc898>] (__netif_receive_skb_one_core) from [<814bc960>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5783)
 r5:dddd11b0 r4:82fba780
[<814bc948>] (__netif_receive_skb) from [<814bcc68>] (process_backlog+0xa0/0x17c net/core/dev.c:6115)
 r5:dddd11b0 r4:82fba780
[<814bcbc8>] (process_backlog) from [<814bdb74>] (__napi_poll+0x34/0x240 net/core/dev.c:6779)
 r10:dddd10c0 r9:dddd1300 r8:df855e38 r7:df855e33 r6:00000040 r5:dddd11b0
 r4:00000001
[<814bdb40>] (__napi_poll) from [<814be3e8>] (napi_poll net/core/dev.c:6848 [inline])
[<814bdb40>] (__napi_poll) from [<814be3e8>] (net_rx_action+0x358/0x440 net/core/dev.c:6970)
 r9:dddd1300 r8:df855e38 r7:0000012c r6:00020966 r5:dddd11b0 r4:00000000
[<814be090>] (net_rx_action) from [<8024b55c>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554)
 r10:00000008 r9:82e3b000 r8:00000100 r7:04208040 r6:00000003 r5:00000004
 r4:8260408c
[<8024b404>] (handle_softirqs) from [<8024b8ac>] (run_ksoftirqd kernel/softirq.c:927 [inline])
[<8024b404>] (handle_softirqs) from [<8024b8ac>] (run_ksoftirqd+0x44/0x4c kernel/softirq.c:919)
 r10:00000000 r9:00000002 r8:82624734 r7:00000001 r6:82e3b000 r5:82cb7100
 r4:00000000
[<8024b868>] (run_ksoftirqd) from [<80275154>] (smpboot_thread_fn+0x16c/0x284 kernel/smpboot.c:164)
[<80274fe8>] (smpboot_thread_fn) from [<8026fd3c>] (kthread+0x104/0x134 kernel/kthread.c:389)
 r10:00000000 r9:df819de8 r8:82cb7240 r7:82cb7100 r6:80274fe8 r5:82e3b000
 r4:82cb7140 r3:00000000
[<8026fc38>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdf855fb0 to 0xdf855ff8)
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 r5:8026fc38 r4:82cb7140
Rebooting in 86400 seconds..