------------[ cut here ]------------
WARNING: CPU: 1 PID: 23 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: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted 6.12.0-rc5-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: 
[<8199bcd8>] (dump_backtrace) from [<8199bdd4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:82622f44 r5:00000000 r4:8203da48
[<8199bdbc>] (show_stack) from [<819ba270>] (__dump_stack lib/dump_stack.c:94 [inline])
[<8199bdbc>] (show_stack) from [<819ba270>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<819ba21c>] (dump_stack_lvl) from [<819ba2b0>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82870d18
[<819ba298>] (dump_stack) from [<8199c900>] (panic+0x120/0x374 kernel/panic.c:354)
[<8199c7e0>] (panic) from [<802420d8>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8199c7e0>] (panic) from [<802420d8>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:82025e1c r0:8202d884
 r7:808401dc
[<80242064>] (check_panic_on_warn) from [<8024223c>] (__warn+0x80/0x188 kernel/panic.c:748)
[<802421bc>] (__warn) from [<8024252c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783)
 r8:00000009 r7:8208c240 r6:df879bfc r5:82e42400 r4:00000000
[<80242348>] (warn_slowpath_fmt) from [<808401dc>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:20000013 r9:84ad3c5c r8:84112240 r7:00000000 r6:8182b8e4 r5:00000002
 r4:84112240
[<808400a0>] (refcount_warn_saturate) from [<8149aff8>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<808400a0>] (refcount_warn_saturate) from [<8149aff8>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<808400a0>] (refcount_warn_saturate) from [<8149aff8>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<808400a0>] (refcount_warn_saturate) from [<8149aff8>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<808400a0>] (refcount_warn_saturate) from [<8149aff8>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<808400a0>] (refcount_warn_saturate) from [<8149aff8>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<8149ae20>] (sk_skb_reason_drop) from [<8182b8e4>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<8149ae20>] (sk_skb_reason_drop) from [<8182b8e4>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<8149ae20>] (sk_skb_reason_drop) from [<8182b8e4>] (j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline])
[<8149ae20>] (sk_skb_reason_drop) from [<8182b8e4>] (j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline])
[<8149ae20>] (sk_skb_reason_drop) from [<8182b8e4>] (j1939_xtp_rx_cts+0x220/0x3d0 net/can/j1939/transport.c:1484)
 r9:84ad3c5c r8:84112240 r7:841098d8 r6:00000df2 r5:84ad3c00 r4:84ad3c14
[<8182b6c4>] (j1939_xtp_rx_cts) from [<8182c858>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline])
[<8182b6c4>] (j1939_xtp_rx_cts) from [<8182c858>] (j1939_tp_recv+0x3f4/0x530 net/can/j1939/transport.c:2161)
 r10:ddde50c8 r9:00000040 r8:841098d0 r7:84b78000 r6:84b78008 r5:84b78000
 r4:84bd0540
[<8182c464>] (j1939_tp_recv) from [<818262f0>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:84b78000 r6:84b78008 r5:84b78810 r4:84bd0540
[<8182610c>] (j1939_can_recv) from [<8181c0c0>] (deliver net/can/af_can.c:572 [inline])
[<8182610c>] (j1939_can_recv) from [<8181c0c0>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:841a06a0 r7:98c80000 r6:84bd0780 r5:00000001 r4:8497f360
[<8181c024>] (can_rcv_filter) from [<8181ca64>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:841a0000 r6:84822e40 r5:84320000 r4:84bd0780
[<8181c9b0>] (can_receive) from [<8181cb24>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000002 r7:00000000 r6:00000000 r5:8181caa0 r4:84bd0780
[<8181caa0>] (can_rcv) from [<814bbf6c>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5670)
 r5:8181caa0 r4:841a0000
[<814bbf10>] (__netif_receive_skb_one_core) from [<814bbfd8>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5783)
 r5:ddde51b0 r4:84bd0780
[<814bbfc0>] (__netif_receive_skb) from [<814bc2e0>] (process_backlog+0xa0/0x17c net/core/dev.c:6115)
 r5:ddde51b0 r4:84bd0780
[<814bc240>] (process_backlog) from [<814bd1ec>] (__napi_poll+0x34/0x240 net/core/dev.c:6779)
 r10:ddde50c0 r9:ddde5300 r8:df879e38 r7:df879e33 r6:00000040 r5:ddde51b0
 r4:00000001
[<814bd1b8>] (__napi_poll) from [<814bda60>] (napi_poll net/core/dev.c:6848 [inline])
[<814bd1b8>] (__napi_poll) from [<814bda60>] (net_rx_action+0x358/0x440 net/core/dev.c:6970)
 r9:ddde5300 r8:df879e38 r7:0000012c r6:ffffb131 r5:ddde51b0 r4:00000000
[<814bd708>] (net_rx_action) from [<8024b51c>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554)
 r10:00000008 r9:82e42400 r8:00000100 r7:04208040 r6:00000003 r5:00000004
 r4:8260408c
[<8024b3c4>] (handle_softirqs) from [<8024b86c>] (run_ksoftirqd kernel/softirq.c:927 [inline])
[<8024b3c4>] (handle_softirqs) from [<8024b86c>] (run_ksoftirqd+0x44/0x4c kernel/softirq.c:919)
 r10:00000000 r9:00000002 r8:82624734 r7:00000001 r6:82e42400 r5:82cc8480
 r4:00000001
[<8024b828>] (run_ksoftirqd) from [<80275114>] (smpboot_thread_fn+0x16c/0x284 kernel/smpboot.c:164)
[<80274fa8>] (smpboot_thread_fn) from [<8026fcfc>] (kthread+0x104/0x134 kernel/kthread.c:389)
 r10:00000000 r9:df819d60 r8:82cc8700 r7:82cc8480 r6:80274fa8 r5:82e42400
 r4:82cc8600 r3:00000000
[<8026fbf8>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdf879fb0 to 0xdf879ff8)
9fa0:                                     00000000 00000000 00000000 00000000
9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:8026fbf8 r4:82cc8600
Rebooting in 86400 seconds..