------------[ 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-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: 
[<8199d478>] (dump_backtrace) from [<8199d574>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:82622f44 r5:00000000 r4:8203df48
[<8199d55c>] (show_stack) from [<819bba40>] (__dump_stack lib/dump_stack.c:94 [inline])
[<8199d55c>] (show_stack) from [<819bba40>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<819bb9ec>] (dump_stack_lvl) from [<819bba80>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82870d18
[<819bba68>] (dump_stack) from [<8199e0a0>] (panic+0x120/0x374 kernel/panic.c:354)
[<8199df80>] (panic) from [<802420d8>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8199df80>] (panic) from [<802420d8>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:82026320 r0:8202dd88
 r7:80840e00
[<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 r7:8208c770 r6:df879bbc r5:82e42400 r4:00000000
[<80242348>] (warn_slowpath_fmt) from [<80840e00>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:84f12000 r9:845c4259 r8:00000002 r7:00000000 r6:8182aacc r5:00000002
 r4:82eb2e40
[<80840cc4>] (refcount_warn_saturate) from [<8149c5a8>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80840cc4>] (refcount_warn_saturate) from [<8149c5a8>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80840cc4>] (refcount_warn_saturate) from [<8149c5a8>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80840cc4>] (refcount_warn_saturate) from [<8149c5a8>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80840cc4>] (refcount_warn_saturate) from [<8149c5a8>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80840cc4>] (refcount_warn_saturate) from [<8149c5a8>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<8149c3d0>] (sk_skb_reason_drop) from [<8182aacc>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<8149c3d0>] (sk_skb_reason_drop) from [<8182aacc>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<8149c3d0>] (sk_skb_reason_drop) from [<8182aacc>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282)
 r9:845c4259 r8:00000002 r7:00000001 r6:84ff8150 r5:84ff8100 r4:82eb2e40
[<8182aa54>] (j1939_session_destroy) from [<8182cd04>] (__j1939_session_release net/can/j1939/transport.c:294 [inline])
[<8182aa54>] (j1939_session_destroy) from [<8182cd04>] (kref_put include/linux/kref.h:65 [inline])
[<8182aa54>] (j1939_session_destroy) from [<8182cd04>] (j1939_session_put net/can/j1939/transport.c:299 [inline])
[<8182aa54>] (j1939_session_destroy) from [<8182cd04>] (j1939_xtp_rx_dat_one+0x258/0x360 net/can/j1939/transport.c:1940)
 r6:82eb2e40 r5:845c4b5f r4:84ff8100
[<8182caac>] (j1939_xtp_rx_dat_one) from [<8182de14>] (j1939_xtp_rx_dat net/can/j1939/transport.c:1957 [inline])
[<8182caac>] (j1939_xtp_rx_dat_one) from [<8182de14>] (j1939_tp_recv+0x268/0x530 net/can/j1939/transport.c:2151)
 r10:ddde50c8 r9:00000040 r8:845c4250 r7:84f1281c r6:84ff8100 r5:84f12000
 r4:82eb26c0
[<8182dbac>] (j1939_tp_recv) from [<81827a38>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:84f12000 r6:84f12008 r5:84f12810 r4:82eb26c0
[<81827854>] (j1939_can_recv) from [<8181d808>] (deliver net/can/af_can.c:572 [inline])
[<81827854>] (j1939_can_recv) from [<8181d808>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:84db46a0 r7:98ebff00 r6:82eb2540 r5:00000001 r4:84ccb3c0
[<8181d76c>] (can_rcv_filter) from [<8181e1ac>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:84db4000 r6:840917c0 r5:840c0000 r4:82eb2540
[<8181e0f8>] (can_receive) from [<8181e26c>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000002 r7:00000000 r6:00000000 r5:8181e1e8 r4:82eb2540
[<8181e1e8>] (can_rcv) from [<814bd51c>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5670)
 r5:8181e1e8 r4:84db4000
[<814bd4c0>] (__netif_receive_skb_one_core) from [<814bd588>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5783)
 r5:ddde51b0 r4:82eb2540
[<814bd570>] (__netif_receive_skb) from [<814bd890>] (process_backlog+0xa0/0x17c net/core/dev.c:6115)
 r5:ddde51b0 r4:82eb2540
[<814bd7f0>] (process_backlog) from [<814be79c>] (__napi_poll+0x34/0x240 net/core/dev.c:6779)
 r10:ddde50c0 r9:ddde5300 r8:df879e38 r7:df879e33 r6:00000040 r5:ddde51b0
 r4:00000001
[<814be768>] (__napi_poll) from [<814bf010>] (napi_poll net/core/dev.c:6848 [inline])
[<814be768>] (__napi_poll) from [<814bf010>] (net_rx_action+0x358/0x440 net/core/dev.c:6970)
 r9:ddde5300 r8:df879e38 r7:0000012c r6:ffffbfcb r5:ddde51b0 r4:00000000
[<814becb8>] (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 [<80275118>] (smpboot_thread_fn+0x16c/0x284 kernel/smpboot.c:164)
[<80274fac>] (smpboot_thread_fn) from [<8026fd00>] (kthread+0x104/0x134 kernel/kthread.c:389)
 r10:00000000 r9:df819d60 r8:82cc8700 r7:82cc8480 r6:80274fac r5:82e42400
 r4:82cc8600 r3:00000000
[<8026fbfc>] (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 r5:8026fbfc r4:82cc8600
Rebooting in 86400 seconds..