netlink: 4 bytes leftover after parsing attributes in process `syz.0.153'.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4194 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: 4194 Comm: syz.0.153 Not tainted 6.12.0-rc7-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: 
[<8199ca58>] (dump_backtrace) from [<8199cb54>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:82622f44 r5:00000000 r4:8203dc0c
[<8199cb3c>] (show_stack) from [<819bafe8>] (__dump_stack lib/dump_stack.c:94 [inline])
[<8199cb3c>] (show_stack) from [<819bafe8>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<819baf94>] (dump_stack_lvl) from [<819bb028>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82870d18
[<819bb010>] (dump_stack) from [<8199d680>] (panic+0x120/0x374 kernel/panic.c:354)
[<8199d560>] (panic) from [<80242118>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8199d560>] (panic) from [<80242118>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:82025fe0 r0:8202da48
 r7:808408b8
[<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 r7:8208c41c r6:dfb65854 r5:845b0c00 r4:00000000
[<80242388>] (warn_slowpath_fmt) from [<808408b8>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:85016c00 r9:0000006c r8:8370681c r7:00000000 r6:8182a12c r5:00000002
 r4:843dc900
[<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<8149ba10>] (sk_skb_reason_drop) from [<8182a12c>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<8149ba10>] (sk_skb_reason_drop) from [<8182a12c>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<8149ba10>] (sk_skb_reason_drop) from [<8182a12c>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282)
 r9:0000006c r8:8370681c r7:00000000 r6:85016c50 r5:85016c00 r4:843dc900
[<8182a0b4>] (j1939_session_destroy) from [<8182db10>] (__j1939_session_release net/can/j1939/transport.c:294 [inline])
[<8182a0b4>] (j1939_session_destroy) from [<8182db10>] (kref_put include/linux/kref.h:65 [inline])
[<8182a0b4>] (j1939_session_destroy) from [<8182db10>] (j1939_session_put net/can/j1939/transport.c:299 [inline])
[<8182a0b4>] (j1939_session_destroy) from [<8182db10>] (j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline])
[<8182a0b4>] (j1939_session_destroy) from [<8182db10>] (j1939_session_deactivate_locked net/can/j1939/transport.c:1074 [inline])
[<8182a0b4>] (j1939_session_destroy) from [<8182db10>] (j1939_cancel_active_session+0x1f0/0x1fc net/can/j1939/transport.c:2211)
 r6:83706814 r5:85016c04 r4:83706810
[<8182d920>] (j1939_cancel_active_session) from [<81826e6c>] (j1939_netdev_notify+0x108/0x150 net/can/j1939/main.c:376)
 r10:845b0c00 r9:00000000 r8:ffffffcd r7:00000001 r6:83706000 r5:00000002
 r4:83706810
[<81826d64>] (j1939_netdev_notify) from [<80271530>] (notifier_call_chain+0x74/0x1ac kernel/notifier.c:93)
 r7:00000001 r6:827e8f24 r5:827e8f44 r4:81826d64
[<802714bc>] (notifier_call_chain) from [<8027174c>] (raw_notifier_call_chain+0x20/0x28 kernel/notifier.c:461)
 r10:821f8f4c r9:00000000 r8:84654000 r7:00000001 r6:845a0000 r5:00000002
 r4:dfb659dc
[<8027172c>] (raw_notifier_call_chain) from [<814b688c>] (call_netdevice_notifiers_info+0x54/0xa0 net/core/dev.c:1996)
[<814b6838>] (call_netdevice_notifiers_info) from [<814b6d28>] (call_netdevice_notifiers_extack net/core/dev.c:2034 [inline])
[<814b6838>] (call_netdevice_notifiers_info) from [<814b6d28>] (call_netdevice_notifiers net/core/dev.c:2048 [inline])
[<814b6838>] (call_netdevice_notifiers_info) from [<814b6d28>] (dev_close_many+0xfc/0x150 net/core/dev.c:1589)
 r6:dfb65a48 r5:dfb6592c r4:8465411c
[<814b6c2c>] (dev_close_many) from [<814c2278>] (unregister_netdevice_many_notify+0x194/0x9c0 net/core/dev.c:11381)
 r9:00000001 r8:dfb65a48 r7:8465411c r6:dfb65ab0 r5:dfb65a48 r4:dfb6599c
[<814c20e4>] (unregister_netdevice_many_notify) from [<814d1ee4>] (rtnl_delete_link net/core/rtnetlink.c:3281 [inline])
[<814c20e4>] (unregister_netdevice_many_notify) from [<814d1ee4>] (rtnl_dellink+0x134/0x354 net/core/rtnetlink.c:3333)
 r10:00000001 r9:00000000 r8:000000b1 r7:845a0000 r6:ffffffff r5:850606c0
 r4:83f4e6c0
[<814d1db0>] (rtnl_dellink) from [<814d062c>] (rtnetlink_rcv_msg+0x138/0x334 net/core/rtnetlink.c:6675)
 r9:00000000 r8:82921c98 r7:850606c0 r6:82921c98 r5:00000001 r4:83f4e6c0
[<814d04f4>] (rtnetlink_rcv_msg) from [<815aa380>] (netlink_rcv_skb+0xc0/0x120 net/netlink/af_netlink.c:2551)
 r10:00000000 r9:00000000 r8:845a0000 r7:00000024 r6:83f4e6c0 r5:814d04f4
 r4:850606c0
[<815aa2c0>] (netlink_rcv_skb) from [<814ceee8>] (rtnetlink_rcv+0x18/0x1c net/core/rtnetlink.c:6693)
 r7:850606c0 r6:843f4ec0 r5:00000024 r4:83d2ec00
[<814ceed0>] (rtnetlink_rcv) from [<815a9b68>] (netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline])
[<814ceed0>] (rtnetlink_rcv) from [<815a9b68>] (netlink_unicast+0x19c/0x29c net/netlink/af_netlink.c:1357)
[<815a99cc>] (netlink_unicast) from [<815a9e44>] (netlink_sendmsg+0x1dc/0x43c net/netlink/af_netlink.c:1901)
 r9:00000000 r8:00000000 r7:84b7ac00 r6:00000024 r5:850606c0 r4:dfb65f38
[<815a9c68>] (netlink_sendmsg) from [<8148687c>] (sock_sendmsg_nosec net/socket.c:729 [inline])
[<815a9c68>] (netlink_sendmsg) from [<8148687c>] (__sock_sendmsg+0x44/0x78 net/socket.c:744)
 r10:00000000 r9:dfb65dd4 r8:dfb65dd4 r7:84cfe000 r6:84cfe000 r5:dfb65f38
 r4:00000000
[<81486838>] (__sock_sendmsg) from [<8148787c>] (____sys_sendmsg+0x2a4/0x2c4 net/socket.c:2607)
 r7:84cfe000 r6:00000000 r5:00048014 r4:dfb65f38
[<814875d8>] (____sys_sendmsg) from [<814897e4>] (___sys_sendmsg+0x9c/0xd0 net/socket.c:2661)
 r10:dfb65e34 r9:20000140 r8:00048014 r7:00000000 r6:84cfe000 r5:dfb65f38
 r4:00000000
[<81489748>] (___sys_sendmsg) from [<81489cfc>] (__sys_sendmsg net/socket.c:2690 [inline])
[<81489748>] (___sys_sendmsg) from [<81489cfc>] (__do_sys_sendmsg net/socket.c:2699 [inline])
[<81489748>] (___sys_sendmsg) from [<81489cfc>] (sys_sendmsg+0x78/0xbc net/socket.c:2697)
 r10:00000128 r9:845b0c00 r8:8020029c r7:00048014 r6:20000140 r5:84cfe000
 r4:00000000
[<81489c84>] (sys_sendmsg) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xdfb65fa8 to 0xdfb65ff0)
5fa0:                   00000000 00000000 00000006 20000140 00048014 00000000
5fc0: 00000000 00000000 002862f0 00000128 00000000 00006364 003d0f00 76b8b0bc
5fe0: 76b8aec0 76b8aeb0 00018b10 00133470
 r7:00000128 r6:002862f0 r5:00000000 r4:00000000
Rebooting in 86400 seconds..