------------[ cut here ]------------
WARNING: CPU: 1 PID: 3781 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: 3781 Comm: syz.0.5 Not tainted 6.12.0-rc6-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: 
[<8199c7b8>] (dump_backtrace) from [<8199c8b4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:82622f44 r5:00000000 r4:8203db14
[<8199c89c>] (show_stack) from [<819bad50>] (__dump_stack lib/dump_stack.c:94 [inline])
[<8199c89c>] (show_stack) from [<819bad50>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<819bacfc>] (dump_stack_lvl) from [<819bad90>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82870d18
[<819bad78>] (dump_stack) from [<8199d3e0>] (panic+0x120/0x374 kernel/panic.c:354)
[<8199d2c0>] (panic) from [<80242118>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8199d2c0>] (panic) from [<80242118>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:82025ee8 r0:8202d950
 r7:80840670
[<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 r7:8208c310 r6:dfea5d6c r5:84010000 r4:00000000
[<80242388>] (warn_slowpath_fmt) from [<80840670>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:00000166 r9:8464fa80 r8:0000006c r7:00000000 r6:81829e84 r5:00000002
 r4:84b1cc00
[<80840534>] (refcount_warn_saturate) from [<8149b940>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b940>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b940>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b940>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b940>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80840534>] (refcount_warn_saturate) from [<8149b940>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<8149b768>] (sk_skb_reason_drop) from [<81829e84>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<8149b768>] (sk_skb_reason_drop) from [<81829e84>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<8149b768>] (sk_skb_reason_drop) from [<81829e84>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282)
 r9:8464fa80 r8:0000006c r7:8464fa84 r6:84b1a950 r5:84b1a900 r4:84b1cc00
[<81829e0c>] (j1939_session_destroy) from [<8182b1a0>] (__j1939_session_release net/can/j1939/transport.c:294 [inline])
[<81829e0c>] (j1939_session_destroy) from [<8182b1a0>] (kref_put include/linux/kref.h:65 [inline])
[<81829e0c>] (j1939_session_destroy) from [<8182b1a0>] (j1939_session_put+0x54/0x58 net/can/j1939/transport.c:299)
 r6:8464fa78 r5:8464fa78 r4:8464fa78
[<8182b14c>] (j1939_session_put) from [<81828260>] (j1939_sk_queue_drop_all+0x7c/0xc4 net/can/j1939/socket.c:144)
[<818281e4>] (j1939_sk_queue_drop_all) from [<818284a0>] (j1939_sk_release+0x1f8/0x200 net/can/j1939/socket.c:642)
 r9:84010000 r8:82cae790 r7:8464fa74 r6:8478b000 r5:84c3fb80 r4:8464f800
[<818282a8>] (j1939_sk_release) from [<81484f6c>] (__sock_release+0x44/0xbc net/socket.c:658)
 r8:82cae790 r7:00000000 r6:81c7e7d4 r5:84c3fc80 r4:84c3fb80
[<81484f28>] (__sock_release) from [<81484ffc>] (sock_close+0x18/0x20 net/socket.c:1426)
 r7:84c3fc00 r6:8311de58 r5:082e0003 r4:84502c00
[<81484fe4>] (sock_close) from [<80518b40>] (__fput+0xdc/0x2e4 fs/file_table.c:431)
[<80518a64>] (__fput) from [<80518dd0>] (____fput+0x14/0x18 fs/file_table.c:459)
 r9:84010000 r8:82871694 r7:84010000 r6:84010884 r5:84010854 r4:00000000
[<80518dbc>] (____fput) from [<8026c678>] (task_work_run+0x90/0xb8 kernel/task_work.c:239)
[<8026c5e8>] (task_work_run) from [<8020bde0>] (resume_user_mode_work include/linux/resume_user_mode.h:50 [inline])
[<8026c5e8>] (task_work_run) from [<8020bde0>] (do_work_pending+0x448/0x4f8 arch/arm/kernel/signal.c:631)
 r9:84010000 r8:8020029c r7:00000166 r6:8020029c r5:dfea5fb0 r4:84010000
[<8020b998>] (do_work_pending) from [<80200088>] (slow_work_pending+0xc/0x24)
Exception stack(0xdfea5fb0 to 0xdfea5ff8)
5fa0:                                     00000003 00000003 00000000 00000000
5fc0: 00000000 00000000 002862f0 00000166 00000000 00006364 003d0f00 76b7f0bc
5fe0: 76b7eec0 76b7eeb0 00018b10 00133470 60000010 00000004
 r10:00000166 r9:84010000 r8:8020029c r7:00000166 r6:002862f0 r5:00000000
 r4:00000000
Rebooting in 86400 seconds..