------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 9172 at lib/refcount.c:28 refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 9172 Comm: syz.0.1746 Not tainted 6.12.0-rc1-syzkaller-00165-g360c1f1f24c6 #0
Hardware name: linux,dummy-virt (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
lr : refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
sp : ffff80008fc676c0
x29: ffff80008fc676c0 x28: ffff00001c290adc x27: 0000000000000002
x26: 1fffe00002f92300 x25: 1fffe00002f92318 x24: ffff000017c918c2
x23: ffff00001c290adc x22: 0000000000000000 x21: ffff800084d67e94
x20: ffff00001c290adc x19: 0000000000000003 x18: 0000000094e64b70
x17: 0000000000000000 x16: 0000000000000000 x15: ffff00000fb52880
x14: 1fffe00001f6a50f x13: 1fffe00001f6a519 x12: ffff600002f4a601
x11: 1fffe00002f4a600 x10: ffff600002f4a600 x9 : dfff800000000000
x8 : ffff000017a53003 x7 : 0000000000000001 x6 : ffff600002f4a600
x5 : ffff000017a53000 x4 : ffff600002f4a601 x3 : ffff800080230758
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff00000fb51e00
Call trace:
 refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
 __refcount_sub_and_test include/linux/refcount.h:275 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 skb_unref include/linux/skbuff.h:1232 [inline]
 __sk_skb_reason_drop net/core/skbuff.c:1213 [inline]
 sk_skb_reason_drop+0x154/0x174 net/core/skbuff.c:1241
 kfree_skb_reason include/linux/skbuff.h:1262 [inline]
 kfree_skb include/linux/skbuff.h:1271 [inline]
 j1939_session_destroy+0x104/0x36c net/can/j1939/transport.c:282
 __j1939_session_release net/can/j1939/transport.c:294 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put+0x80/0xac net/can/j1939/transport.c:299
 j1939_sk_send_loop net/can/j1939/socket.c:1202 [inline]
 j1939_sk_sendmsg+0xaf4/0xf60 net/can/j1939/socket.c:1277
 sock_sendmsg_nosec net/socket.c:729 [inline]
 __sock_sendmsg+0xc8/0x168 net/socket.c:744
 ____sys_sendmsg+0x54c/0x6dc net/socket.c:2602
 ___sys_sendmsg+0x11c/0x19c net/socket.c:2656
 __sys_sendmsg+0xe0/0x174 net/socket.c:2685
 __do_sys_sendmsg net/socket.c:2694 [inline]
 __se_sys_sendmsg net/socket.c:2692 [inline]
 __arm64_sys_sendmsg+0x70/0xa0 net/socket.c:2692
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x50/0x180 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
irq event stamp: 632
hardirqs last  enabled at (631): [<ffff8000802303e4>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1517 [inline]
hardirqs last  enabled at (631): [<ffff8000802303e4>] finish_lock_switch kernel/sched/core.c:5069 [inline]
hardirqs last  enabled at (631): [<ffff8000802303e4>] finish_task_switch.isra.0+0x1a8/0x8e0 kernel/sched/core.c:5187
hardirqs last disabled at (632): [<ffff8000851a2410>] el1_dbg+0x24/0x9c arch/arm64/kernel/entry-common.c:470
softirqs last  enabled at (616): [<ffff80008019e1a4>] softirq_handle_end kernel/softirq.c:400 [inline]
softirqs last  enabled at (616): [<ffff80008019e1a4>] handle_softirqs+0x878/0xd40 kernel/softirq.c:582
softirqs last disabled at (577): [<ffff800080010758>] __do_softirq+0x14/0x20 kernel/softirq.c:588
---[ end trace 0000000000000000 ]---