------------[ cut here ]------------
WARNING: CPU: 0 PID: 5098 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: 5098 Comm: syz.1.387 Not tainted 6.12.0-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: 
[<819b7fb8>] (dump_backtrace) from [<819b80b4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:82623304 r5:00000000 r4:820413b8
[<819b809c>] (show_stack) from [<819d60dc>] (__dump_stack lib/dump_stack.c:94 [inline])
[<819b809c>] (show_stack) from [<819d60dc>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<819d6088>] (dump_stack_lvl) from [<819d611c>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82874d18
[<819d6104>] (dump_stack) from [<819b8be0>] (panic+0x120/0x374 kernel/panic.c:354)
[<819b8ac0>] (panic) from [<802426d0>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<819b8ac0>] (panic) from [<802426d0>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c604 r2:00000001 r1:82029878 r0:82031344
 r7:8084bbd8
[<8024265c>] (check_panic_on_warn) from [<80242834>] (__warn+0x80/0x188 kernel/panic.c:748)
[<802427b4>] (__warn) from [<80242b24>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783)
 r8:00000009 r7:8209017c r6:e0089d6c r5:847ac800 r4:00000000
[<80242940>] (warn_slowpath_fmt) from [<8084bbd8>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:000001b4 r9:85461680 r8:0000006c r7:00000000 r6:81841f64 r5:00000002
 r4:85285a80
[<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (skb_unref include/linux/skbuff.h:1233 [inline])
[<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<814aa79c>] (sk_skb_reason_drop) from [<81841f64>] (kfree_skb_reason include/linux/skbuff.h:1263 [inline])
[<814aa79c>] (sk_skb_reason_drop) from [<81841f64>] (kfree_skb include/linux/skbuff.h:1272 [inline])
[<814aa79c>] (sk_skb_reason_drop) from [<81841f64>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282)
 r9:85461680 r8:0000006c r7:85461684 r6:83890b50 r5:83890b00 r4:85285a80
[<81841eec>] (j1939_session_destroy) from [<81843280>] (__j1939_session_release net/can/j1939/transport.c:294 [inline])
[<81841eec>] (j1939_session_destroy) from [<81843280>] (kref_put include/linux/kref.h:65 [inline])
[<81841eec>] (j1939_session_destroy) from [<81843280>] (j1939_session_put+0x54/0x58 net/can/j1939/transport.c:299)
 r6:85461678 r5:85461678 r4:85461678
[<8184322c>] (j1939_session_put) from [<81840340>] (j1939_sk_queue_drop_all+0x7c/0xc4 net/can/j1939/socket.c:144)
[<818402c4>] (j1939_sk_queue_drop_all) from [<81840580>] (j1939_sk_release+0x1f8/0x200 net/can/j1939/socket.c:642)
 r9:847ac800 r8:82caf610 r7:85461674 r6:84589000 r5:8337c280 r4:85461400
[<81840388>] (j1939_sk_release) from [<81493fdc>] (__sock_release+0x44/0xbc net/socket.c:640)
 r8:82caf610 r7:00000000 r6:81c7ecc0 r5:8337c380 r4:8337c280
[<81493f98>] (__sock_release) from [<8149406c>] (sock_close+0x18/0x20 net/socket.c:1408)
 r7:8337c300 r6:83307bb0 r5:082e0003 r4:85026c00
[<81494054>] (sock_close) from [<8051f748>] (__fput+0xdc/0x2f0 fs/file_table.c:450)
[<8051f66c>] (__fput) from [<8051f9e4>] (____fput+0x14/0x18 fs/file_table.c:478)
 r9:847ac800 r8:82875694 r7:847ac800 r6:847ad084 r5:847ad054 r4:85026d28
[<8051f9d0>] (____fput) from [<8026d41c>] (task_work_run+0x90/0xb8 kernel/task_work.c:239)
[<8026d38c>] (task_work_run) from [<8020be00>] (resume_user_mode_work include/linux/resume_user_mode.h:50 [inline])
[<8026d38c>] (task_work_run) from [<8020be00>] (do_work_pending+0x448/0x4f8 arch/arm/kernel/signal.c:631)
 r9:847ac800 r8:8020029c r7:000001b4 r6:8020029c r5:e0089fb0 r4:847ac800
[<8020b9b8>] (do_work_pending) from [<80200088>] (slow_work_pending+0xc/0x24)
Exception stack(0xe0089fb0 to 0xe0089ff8)
9fa0:                                     00000000 ffffffff 00000000 00000000
9fc0: 00000000 00000000 002862f0 000001b4 00000000 00006364 003d0f00 76bf60bc
9fe0: 76bf5ec0 76bf5eb0 00018af0 00133450 60000010 00000004
 r10:000001b4 r9:847ac800 r8:8020029c r7:000001b4 r6:002862f0 r5:00000000
 r4:00000000
Rebooting in 86400 seconds..