netlink: 4 bytes leftover after parsing attributes in process `syz.0.3054'.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 17494 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: 17494 Comm: syz.0.3054 Not tainted 6.11.0-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: 
[<819839d8>] (dump_backtrace) from [<81983ad4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:826228c4 r5:00000000 r4:82035550
[<81983abc>] (show_stack) from [<819a1a38>] (__dump_stack lib/dump_stack.c:93 [inline])
[<81983abc>] (show_stack) from [<819a1a38>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:119)
[<819a19e4>] (dump_stack_lvl) from [<819a1a78>] (dump_stack+0x18/0x1c lib/dump_stack.c:128)
 r5:00000000 r4:8286ed18
[<819a1a60>] (dump_stack) from [<8198457c>] (panic+0x120/0x370 kernel/panic.c:354)
[<8198445c>] (panic) from [<802421cc>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8198445c>] (panic) from [<802421cc>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:8201dd08 r0:82025ad4
 r7:80832e10
[<80242158>] (check_panic_on_warn) from [<8024232c>] (__warn+0x80/0x188 kernel/panic.c:748)
[<802422ac>] (__warn) from [<8024261c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783)
 r8:00000009 r7:82084040 r6:e0539854 r5:835c8000 r4:00000000
[<80242438>] (warn_slowpath_fmt) from [<80832e10>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:8850e100 r9:0000006c r8:847db81c r7:00000000 r6:81811b44 r5:00000002
 r4:84acc240
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<8148453c>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<81484364>] (sk_skb_reason_drop) from [<81811b44>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<81484364>] (sk_skb_reason_drop) from [<81811b44>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<81484364>] (sk_skb_reason_drop) from [<81811b44>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282)
 r9:0000006c r8:847db81c r7:00000000 r6:8850e150 r5:8850e100 r4:84acc240
[<81811acc>] (j1939_session_destroy) from [<81815528>] (__j1939_session_release net/can/j1939/transport.c:294 [inline])
[<81811acc>] (j1939_session_destroy) from [<81815528>] (kref_put include/linux/kref.h:65 [inline])
[<81811acc>] (j1939_session_destroy) from [<81815528>] (j1939_session_put net/can/j1939/transport.c:299 [inline])
[<81811acc>] (j1939_session_destroy) from [<81815528>] (j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline])
[<81811acc>] (j1939_session_destroy) from [<81815528>] (j1939_session_deactivate_locked net/can/j1939/transport.c:1074 [inline])
[<81811acc>] (j1939_session_destroy) from [<81815528>] (j1939_cancel_active_session+0x1f0/0x1fc net/can/j1939/transport.c:2211)
 r6:847db814 r5:8850e104 r4:847db810
[<81815338>] (j1939_cancel_active_session) from [<8180e884>] (j1939_netdev_notify+0x108/0x150 net/can/j1939/main.c:376)
 r10:835c8000 r9:00000000 r8:ffffffcd r7:00000001 r6:847db000 r5:00000002
 r4:847db810
[<8180e77c>] (j1939_netdev_notify) from [<80271384>] (notifier_call_chain+0x74/0x1ac kernel/notifier.c:93)
 r7:00000001 r6:827e7364 r5:827e7384 r4:8180e77c
[<80271310>] (notifier_call_chain) from [<802715a0>] (raw_notifier_call_chain+0x20/0x28 kernel/notifier.c:461)
 r10:821efcfc r9:00000000 r8:859e4000 r7:00000001 r6:84204100 r5:00000002
 r4:e05399dc
[<80271580>] (raw_notifier_call_chain) from [<8149f274>] (call_netdevice_notifiers_info+0x54/0xa0 net/core/dev.c:1996)
[<8149f220>] (call_netdevice_notifiers_info) from [<8149f710>] (call_netdevice_notifiers_extack net/core/dev.c:2034 [inline])
[<8149f220>] (call_netdevice_notifiers_info) from [<8149f710>] (call_netdevice_notifiers net/core/dev.c:2048 [inline])
[<8149f220>] (call_netdevice_notifiers_info) from [<8149f710>] (dev_close_many+0xfc/0x150 net/core/dev.c:1589)
 r6:e0539a48 r5:84914000 r4:859e411c
[<8149f614>] (dev_close_many) from [<814aaa74>] (unregister_netdevice_many_notify+0x194/0x9c0 net/core/dev.c:11373)
 r9:00000001 r8:e0539a48 r7:8491411c r6:e0539ab0 r5:859e411c r4:e053999c
[<814aa8e0>] (unregister_netdevice_many_notify) from [<814ba650>] (rtnl_delete_link net/core/rtnetlink.c:3252 [inline])
[<814aa8e0>] (unregister_netdevice_many_notify) from [<814ba650>] (rtnl_dellink+0x134/0x354 net/core/rtnetlink.c:3304)
 r10:00000001 r9:00000000 r8:00000113 r7:84204100 r6:ffffffff r5:84ac9300
 r4:859e0000
[<814ba51c>] (rtnl_dellink) from [<814b8d98>] (rtnetlink_rcv_msg+0x138/0x334 net/core/rtnetlink.c:6646)
 r9:00000000 r8:8291fbd8 r7:84ac9300 r6:8291fbd8 r5:00000001 r4:859e0000
[<814b8c60>] (rtnetlink_rcv_msg) from [<81592b80>] (netlink_rcv_skb+0xc0/0x120 net/netlink/af_netlink.c:2550)
 r10:00000000 r9:00000000 r8:84204100 r7:00000024 r6:859e0000 r5:814b8c60
 r4:84ac9300
[<81592ac0>] (netlink_rcv_skb) from [<814b7738>] (rtnetlink_rcv+0x18/0x1c net/core/rtnetlink.c:6664)
 r7:84ac9300 r6:859f6ec0 r5:00000024 r4:8441ec00
[<814b7720>] (rtnetlink_rcv) from [<81592368>] (netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline])
[<814b7720>] (rtnetlink_rcv) from [<81592368>] (netlink_unicast+0x19c/0x29c net/netlink/af_netlink.c:1357)
[<815921cc>] (netlink_unicast) from [<81592644>] (netlink_sendmsg+0x1dc/0x43c net/netlink/af_netlink.c:1901)
 r9:00000000 r8:00000000 r7:8474b400 r6:00000024 r5:84ac9300 r4:e0539f38
[<81592468>] (netlink_sendmsg) from [<8146f24c>] (sock_sendmsg_nosec net/socket.c:730 [inline])
[<81592468>] (netlink_sendmsg) from [<8146f24c>] (__sock_sendmsg+0x44/0x78 net/socket.c:745)
 r10:00000000 r9:e0539dd4 r8:e0539dd4 r7:00000000 r6:83354000 r5:e0539f38
 r4:00000000
[<8146f208>] (__sock_sendmsg) from [<81470250>] (____sys_sendmsg+0x2ac/0x2cc net/socket.c:2603)
 r7:00000000 r6:00000000 r5:83354000 r4:e0539f38
[<8146ffa4>] (____sys_sendmsg) from [<814721bc>] (___sys_sendmsg+0x9c/0xd0 net/socket.c:2657)
 r10:e0539e34 r9:20000200 r8:00000000 r7:00000000 r6:83354000 r5:e0539f38
 r4:00000000
[<81472120>] (___sys_sendmsg) from [<814726d4>] (__sys_sendmsg net/socket.c:2686 [inline])
[<81472120>] (___sys_sendmsg) from [<814726d4>] (__do_sys_sendmsg net/socket.c:2695 [inline])
[<81472120>] (___sys_sendmsg) from [<814726d4>] (sys_sendmsg+0x78/0xbc net/socket.c:2693)
 r10:00000128 r9:835c8000 r8:8020029c r7:00000000 r6:20000200 r5:83354000
 r4:00000000
[<8147265c>] (sys_sendmsg) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xe0539fa8 to 0xe0539ff0)
9fa0:                   00000000 00000000 00000006 20000200 00000000 00000000
9fc0: 00000000 00000000 002862f0 00000128 00000000 00006364 003d0f00 76b870bc
9fe0: 76b86ec0 76b86eb0 000189d0 00132da0
 r7:00000128 r6:002862f0 r5:00000000 r4:00000000
Rebooting in 86400 seconds..