------------[ 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 6.11.0-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: 
[<819839d8>] (dump_backtrace) from [<81983ad4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:826228c4 r5:00000000 r4:82035550
[<81983abc>] (show_stack) from [<819a1a38>] (__dump_stack lib/dump_stack.c:93 [inline])
[<81983abc>] (show_stack) from [<819a1a38>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:119)
[<819a19e4>] (dump_stack_lvl) from [<819a1a78>] (dump_stack+0x18/0x1c lib/dump_stack.c:128)
 r5:00000000 r4:8286ed18
[<819a1a60>] (dump_stack) from [<8198457c>] (panic+0x120/0x370 kernel/panic.c:354)
[<8198445c>] (panic) from [<802421cc>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8198445c>] (panic) from [<802421cc>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:8201dd08 r0:82025ad4
 r7:80832e10
[<80242158>] (check_panic_on_warn) from [<8024232c>] (__warn+0x80/0x188 kernel/panic.c:748)
[<802422ac>] (__warn) from [<8024261c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783)
 r8:00000009 r7:82084040 r6:df879bfc r5:82e42400 r4:00000000
[<80242438>] (warn_slowpath_fmt) from [<80832e10>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:20000013 r9:84a53a5c r8:84e4b900 r7:00000000 r6:818140a4 r5:00000002
 r4:84e4b900
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<81484364>] (sk_skb_reason_drop) from [<818140a4>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<81484364>] (sk_skb_reason_drop) from [<818140a4>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<81484364>] (sk_skb_reason_drop) from [<818140a4>] (j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline])
[<81484364>] (sk_skb_reason_drop) from [<818140a4>] (j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline])
[<81484364>] (sk_skb_reason_drop) from [<818140a4>] (j1939_xtp_rx_cts+0x220/0x3d0 net/can/j1939/transport.c:1484)
 r9:84a53a5c r8:84e4b900 r7:8538e6d8 r6:00000df2 r5:84a53a00 r4:84a53a14
[<81813e84>] (j1939_xtp_rx_cts) from [<81815018>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline])
[<81813e84>] (j1939_xtp_rx_cts) from [<81815018>] (j1939_tp_recv+0x3f4/0x530 net/can/j1939/transport.c:2161)
 r10:ddde4ec8 r9:00000040 r8:8538e6d0 r7:840eb000 r6:840eb008 r5:840eb000
 r4:849ef840
[<81814c24>] (j1939_tp_recv) from [<8180eab0>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:840eb000 r6:840eb008 r5:840eb810 r4:849ef840
[<8180e8cc>] (j1939_can_recv) from [<8180487c>] (deliver net/can/af_can.c:572 [inline])
[<8180e8cc>] (j1939_can_recv) from [<8180487c>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:84a586a0 r7:98c80000 r6:849efa80 r5:00000001 r4:85071450
[<818047e0>] (can_rcv_filter) from [<81805220>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:84a58000 r6:84f80a40 r5:843a9a00 r4:849efa80
[<8180516c>] (can_receive) from [<818052e0>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000002 r7:00000000 r6:00000000 r5:8180525c r4:849efa80
[<8180525c>] (can_rcv) from [<814a53b4>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5662)
 r5:8180525c r4:84a58000
[<814a5358>] (__netif_receive_skb_one_core) from [<814a5420>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5775)
 r5:ddde4fb0 r4:849efa80
[<814a5408>] (__netif_receive_skb) from [<814a5710>] (process_backlog+0x88/0x15c net/core/dev.c:6107)
 r5:ddde4fb0 r4:849efa80
[<814a5688>] (process_backlog) from [<814a6614>] (__napi_poll+0x34/0x240 net/core/dev.c:6771)
 r10:ddde4ec0 r9:ddde5100 r8:df879e38 r7:df879e33 r6:00000040 r5:ddde4fb0
 r4:00000001
[<814a65e0>] (__napi_poll) from [<814a6e4c>] (napi_poll net/core/dev.c:6840 [inline])
[<814a65e0>] (__napi_poll) from [<814a6e4c>] (net_rx_action+0x338/0x420 net/core/dev.c:6962)
 r9:ddde5100 r8:df879e38 r7:0000012c r6:00025636 r5:ddde4fb0 r4:00000000
[<814a6b14>] (net_rx_action) from [<8024b5e0>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554)
 r10:00000008 r9:82e42400 r8:00000100 r7:04208040 r6:00000003 r5:00000004
 r4:8260408c
[<8024b488>] (handle_softirqs) from [<8024b930>] (run_ksoftirqd kernel/softirq.c:927 [inline])
[<8024b488>] (handle_softirqs) from [<8024b930>] (run_ksoftirqd+0x44/0x4c kernel/softirq.c:919)
 r10:00000000 r9:00000002 r8:826240dc r7:00000001 r6:82cc7480 r5:82e42400
 r4:00000001
[<8024b8ec>] (run_ksoftirqd) from [<80274fc0>] (smpboot_thread_fn+0x16c/0x288 kernel/smpboot.c:164)
[<80274e54>] (smpboot_thread_fn) from [<8026fb98>] (kthread+0x104/0x134 kernel/kthread.c:389)
 r10:00000000 r9:df819d60 r8:82cc7700 r7:82cc7480 r6:80274e54 r5:82e42400
 r4:82cc7600 r3:00000000
[<8026fa94>] (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 r5:8026fa94 r4:82cc7600
Rebooting in 86400 seconds..