------------[ 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: 
[<8199c3f8>] (dump_backtrace) from [<8199c4f4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:82622f44 r5:00000000 r4:8203db20
[<8199c4dc>] (show_stack) from [<819ba990>] (__dump_stack lib/dump_stack.c:94 [inline])
[<8199c4dc>] (show_stack) from [<819ba990>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<819ba93c>] (dump_stack_lvl) from [<819ba9d0>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82870d18
[<819ba9b8>] (dump_stack) from [<8199d020>] (panic+0x120/0x374 kernel/panic.c:354)
[<8199cf00>] (panic) from [<80242118>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8199cf00>] (panic) from [<80242118>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:82025ef4 r0:8202d95c
 r7:80840678
[<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 r7:8208c31c r6:df855bbc r5:82e3b000 r4:00000000
[<80242388>] (warn_slowpath_fmt) from [<80840678>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:85334000 r9:85421459 r8:00000006 r7:00000000 r6:81829ab4 r5:00000002
 r4:8517acc0
[<8084053c>] (refcount_warn_saturate) from [<8149b728>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<8084053c>] (refcount_warn_saturate) from [<8149b728>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<8084053c>] (refcount_warn_saturate) from [<8149b728>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<8084053c>] (refcount_warn_saturate) from [<8149b728>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<8084053c>] (refcount_warn_saturate) from [<8149b728>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<8084053c>] (refcount_warn_saturate) from [<8149b728>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<8149b550>] (sk_skb_reason_drop) from [<81829ab4>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<8149b550>] (sk_skb_reason_drop) from [<81829ab4>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<8149b550>] (sk_skb_reason_drop) from [<81829ab4>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282)
 r9:85421459 r8:00000006 r7:0000000a r6:84c4bc50 r5:84c4bc00 r4:8517acc0
[<81829a3c>] (j1939_session_destroy) from [<8182bcec>] (__j1939_session_release net/can/j1939/transport.c:294 [inline])
[<81829a3c>] (j1939_session_destroy) from [<8182bcec>] (kref_put include/linux/kref.h:65 [inline])
[<81829a3c>] (j1939_session_destroy) from [<8182bcec>] (j1939_session_put net/can/j1939/transport.c:299 [inline])
[<81829a3c>] (j1939_session_destroy) from [<8182bcec>] (j1939_xtp_rx_dat_one+0x258/0x360 net/can/j1939/transport.c:1940)
 r6:8517acc0 r5:85420dde r4:84c4bc00
[<8182ba94>] (j1939_xtp_rx_dat_one) from [<8182cdfc>] (j1939_xtp_rx_dat net/can/j1939/transport.c:1957 [inline])
[<8182ba94>] (j1939_xtp_rx_dat_one) from [<8182cdfc>] (j1939_tp_recv+0x268/0x530 net/can/j1939/transport.c:2151)
 r10:dddd10c8 r9:00000040 r8:85421450 r7:8533481c r6:84c4bc00 r5:85334000
 r4:8517a300
[<8182cb94>] (j1939_tp_recv) from [<81826a20>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:85334000 r6:85334008 r5:85334810 r4:8517a300
[<8182683c>] (j1939_can_recv) from [<8181c7f0>] (deliver net/can/af_can.c:572 [inline])
[<8182683c>] (j1939_can_recv) from [<8181c7f0>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:84b84680 r7:98ebff00 r6:8517ad80 r5:00000001 r4:84f726c0
[<8181c754>] (can_rcv_filter) from [<8181d194>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:84b84000 r6:83ee7180 r5:84e50000 r4:8517ad80
[<8181d0e0>] (can_receive) from [<8181d254>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000001 r7:00000000 r6:00000000 r5:8181d1d0 r4:8517ad80
[<8181d1d0>] (can_rcv) from [<814bc69c>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5670)
 r5:8181d1d0 r4:84b84000
[<814bc640>] (__netif_receive_skb_one_core) from [<814bc708>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5783)
 r5:dddd11b0 r4:8517ad80
[<814bc6f0>] (__netif_receive_skb) from [<814bca10>] (process_backlog+0xa0/0x17c net/core/dev.c:6115)
 r5:dddd11b0 r4:8517ad80
[<814bc970>] (process_backlog) from [<814bd91c>] (__napi_poll+0x34/0x240 net/core/dev.c:6779)
 r10:dddd10c0 r9:dddd1300 r8:df855e38 r7:df855e33 r6:00000040 r5:dddd11b0
 r4:00000001
[<814bd8e8>] (__napi_poll) from [<814be190>] (napi_poll net/core/dev.c:6848 [inline])
[<814bd8e8>] (__napi_poll) from [<814be190>] (net_rx_action+0x358/0x440 net/core/dev.c:6970)
 r9:dddd1300 r8:df855e38 r7:0000012c r6:00004d94 r5:dddd11b0 r4:00000000
[<814bde38>] (net_rx_action) from [<8024b55c>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554)
 r10:00000002 r9:82e3b000 r8:00000100 r7:04208040 r6:00000003 r5:00000002
 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..