------------[ 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: 
[<81985f40>] (dump_backtrace) from [<8198603c>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:826228c4 r5:00000000 r4:82035a48
[<81986024>] (show_stack) from [<819a431c>] (__dump_stack lib/dump_stack.c:93 [inline])
[<81986024>] (show_stack) from [<819a431c>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:119)
[<819a42c8>] (dump_stack_lvl) from [<819a435c>] (dump_stack+0x18/0x1c lib/dump_stack.c:128)
 r5:00000000 r4:8286dd18
[<819a4344>] (dump_stack) from [<81986b68>] (panic+0x120/0x370 kernel/panic.c:354)
[<81986a48>] (panic) from [<802421dc>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<81986a48>] (panic) from [<802421dc>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:8201e0ec r0:82025eb8
 r7:808348c0
[<80242168>] (check_panic_on_warn) from [<8024233c>] (__warn+0x80/0x188 kernel/panic.c:748)
[<802422bc>] (__warn) from [<8024262c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783)
 r8:00000009 r7:82084ad8 r6:df879bbc r5:82e42400 r4:00000000
[<80242448>] (warn_slowpath_fmt) from [<808348c0>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:846ee000 r9:85365219 r8:00000006 r7:00000000 r6:81813f34 r5:00000002
 r4:8542d300
[<80834784>] (refcount_warn_saturate) from [<814867d0>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80834784>] (refcount_warn_saturate) from [<814867d0>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80834784>] (refcount_warn_saturate) from [<814867d0>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80834784>] (refcount_warn_saturate) from [<814867d0>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80834784>] (refcount_warn_saturate) from [<814867d0>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80834784>] (refcount_warn_saturate) from [<814867d0>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<814865f8>] (sk_skb_reason_drop) from [<81813f34>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<814865f8>] (sk_skb_reason_drop) from [<81813f34>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<814865f8>] (sk_skb_reason_drop) from [<81813f34>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282)
 r9:85365219 r8:00000006 r7:0000000a r6:8512e450 r5:8512e400 r4:8542d300
[<81813ebc>] (j1939_session_destroy) from [<8181616c>] (__j1939_session_release net/can/j1939/transport.c:294 [inline])
[<81813ebc>] (j1939_session_destroy) from [<8181616c>] (kref_put include/linux/kref.h:65 [inline])
[<81813ebc>] (j1939_session_destroy) from [<8181616c>] (j1939_session_put net/can/j1939/transport.c:299 [inline])
[<81813ebc>] (j1939_session_destroy) from [<8181616c>] (j1939_xtp_rx_dat_one+0x258/0x360 net/can/j1939/transport.c:1940)
 r6:8542d300 r5:853656de r4:8512e400
[<81815f14>] (j1939_xtp_rx_dat_one) from [<8181727c>] (j1939_xtp_rx_dat net/can/j1939/transport.c:1957 [inline])
[<81815f14>] (j1939_xtp_rx_dat_one) from [<8181727c>] (j1939_tp_recv+0x268/0x530 net/can/j1939/transport.c:2151)
 r10:ddde5048 r9:00000040 r8:85365210 r7:846ee81c r6:8512e400 r5:846ee000
 r4:8542d780
[<81817014>] (j1939_tp_recv) from [<81810ea0>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:846ee000 r6:846ee008 r5:846ee810 r4:8542d780
[<81810cbc>] (j1939_can_recv) from [<81806c6c>] (deliver net/can/af_can.c:572 [inline])
[<81810cbc>] (j1939_can_recv) from [<81806c6c>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:84d3c680 r7:98ebff00 r6:8542d600 r5:00000001 r4:8511a360
[<81806bd0>] (can_rcv_filter) from [<81807610>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:84d3c000 r6:8476ee00 r5:84f70000 r4:8542d600
[<8180755c>] (can_receive) from [<818076d0>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000001 r7:00000000 r6:00000000 r5:8180764c r4:8542d600
[<8180764c>] (can_rcv) from [<814a7648>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5662)
 r5:8180764c r4:84d3c000
[<814a75ec>] (__netif_receive_skb_one_core) from [<814a76b4>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5775)
 r5:ddde5130 r4:8542d600
[<814a769c>] (__netif_receive_skb) from [<814a79a4>] (process_backlog+0x88/0x15c net/core/dev.c:6107)
 r5:ddde5130 r4:8542d600
[<814a791c>] (process_backlog) from [<814a88a8>] (__napi_poll+0x34/0x240 net/core/dev.c:6771)
 r10:ddde5040 r9:ddde5280 r8:df879e38 r7:df879e33 r6:00000040 r5:ddde5130
 r4:00000001
[<814a8874>] (__napi_poll) from [<814a90e0>] (napi_poll net/core/dev.c:6840 [inline])
[<814a8874>] (__napi_poll) from [<814a90e0>] (net_rx_action+0x338/0x420 net/core/dev.c:6962)
 r9:ddde5280 r8:df879e38 r7:0000012c r6:ffffdc80 r5:ddde5130 r4:00000000
[<814a8da8>] (net_rx_action) from [<8024b604>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554)
 r10:00000008 r9:82e42400 r8:00000100 r7:04208040 r6:00000003 r5:00000004
 r4:8260408c
[<8024b4ac>] (handle_softirqs) from [<8024b954>] (run_ksoftirqd kernel/softirq.c:927 [inline])
[<8024b4ac>] (handle_softirqs) from [<8024b954>] (run_ksoftirqd+0x44/0x4c kernel/softirq.c:919)
 r10:00000000 r9:00000002 r8:826240b4 r7:00000001 r6:82cc7480 r5:82e42400
 r4:00000001
[<8024b910>] (run_ksoftirqd) from [<802750d8>] (smpboot_thread_fn+0x16c/0x288 kernel/smpboot.c:164)
[<80274f6c>] (smpboot_thread_fn) from [<8026fcb0>] (kthread+0x104/0x134 kernel/kthread.c:389)
 r10:00000000 r9:df819d60 r8:82cc7700 r7:82cc7480 r6:80274f6c r5:82e42400
 r4:82cc7600 r3:00000000
[<8026fbac>] (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 r5:8026fbac r4:82cc7600
Rebooting in 86400 seconds..