In the Linux kernel, the following vulnerability has been resolved: bonding: stop the device in bond_setup_by_slave() Commit 9eed321cde22 ("net: lapbether: only support ethernet devices") has been able to keep syzbot away from net/lapb, until today. In the following splat [1], the issue is that a lapbether device has been created on a bonding device without members. Then adding a non ARPHRD_ETHER member forced the bonding master to change its type. The fix is to make sure we call dev_close() in bond_setup_by_slave() so that the potential linked lapbether devices (or any other devices having assumptions on the physical device) are removed. A similar bug has been addressed in commit 40baec225765 ("bonding: fix panic on non-ARPHRD_ETHER enslave failure") [1] skbuff: skb_under_panic: text:ffff800089508810 len:44 put:40 head:ffff0000c78e7c00 data:ffff0000c78e7bea tail:0x16 end:0x140 dev:bond0 kernel BUG at net/core/skbuff.c:192 ! Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 6007 Comm: syz-executor383 Not tainted 6.6.0-rc3-syzkaller-gbf6547d8715b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : skb_panic net/core/skbuff.c:188 [inline] pc : skb_under_panic+0x13c/0x140 net/core/skbuff.c:202 lr : skb_panic net/core/skbuff.c:188 [inline] lr : skb_under_panic+0x13c/0x140 net/core/skbuff.c:202 sp : ffff800096a06aa0 x29: ffff800096a06ab0 x28: ffff800096a06ba0 x27: dfff800000000000 x26: ffff0000ce9b9b50 x25: 0000000000000016 x24: ffff0000c78e7bea x23: ffff0000c78e7c00 x22: 000000000000002c x21: 0000000000000140 x20: 0000000000000028 x19: ffff800089508810 x18: ffff800096a06100 x17: 0000000000000000 x16: ffff80008a629a3c x15: 0000000000000001 x14: 1fffe00036837a32 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000201 x10: 0000000000000000 x9 : cb50b496c519aa00 x8 : cb50b496c519aa00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff800096a063b8 x4 : ffff80008e280f80 x3 : ffff8000805ad11c x2 : 0000000000000001 x1 : 0000000100000201 x0 : 0000000000000086 Call trace: skb_panic net/core/skbuff.c:188 [inline] skb_under_panic+0x13c/0x140 net/core/skbuff.c:202 skb_push+0xf0/0x108 net/core/skbuff.c:2446 ip6gre_header+0xbc/0x738 net/ipv6/ip6_gre.c:1384 dev_hard_header include/linux/netdevice.h:3136 [inline] lapbeth_data_transmit+0x1c4/0x298 drivers/net/wan/lapbether.c:257 lapb_data_transmit+0x8c/0xb0 net/lapb/lapb_iface.c:447 lapb_transmit_buffer+0x178/0x204 net/lapb/lapb_out.c:149 lapb_send_control+0x220/0x320 net/lapb/lapb_subr.c:251 __lapb_disconnect_request+0x9c/0x17c net/lapb/lapb_iface.c:326 lapb_device_event+0x288/0x4e0 net/lapb/lapb_iface.c:492 notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93 raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461 call_netdevice_notifiers_info net/core/dev.c:1970 [inline] call_netdevice_notifiers_extack net/core/dev.c:2008 [inline] call_netdevice_notifiers net/core/dev.c:2022 [inline] __dev_close_many+0x1b8/0x3c4 net/core/dev.c:1508 dev_close_many+0x1e0/0x470 net/core/dev.c:1559 dev_close+0x174/0x250 net/core/dev.c:1585 lapbeth_device_event+0x2e4/0x958 drivers/net/wan/lapbether.c:466 notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93 raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461 call_netdevice_notifiers_info net/core/dev.c:1970 [inline] call_netdevice_notifiers_extack net/core/dev.c:2008 [inline] call_netdevice_notifiers net/core/dev.c:2022 [inline] __dev_close_many+0x1b8/0x3c4 net/core/dev.c:1508 dev_close_many+0x1e0/0x470 net/core/dev.c:1559 dev_close+0x174/0x250 net/core/dev.c:1585 bond_enslave+0x2298/0x30cc drivers/net/bonding/bond_main.c:2332 bond_do_ioctl+0x268/0xc64 drivers/net/bonding/bond_main.c:4539 dev_ifsioc+0x754/0x9ac dev_ioctl+0x4d8/0xd34 net/core/dev_ioctl.c:786 sock_do_ioctl+0x1d4/0x2d0 net/socket.c:1217 sock_ioctl+0x4e8/0x834 net/socket.c:1322 vfs_ioctl fs/ioctl.c:51 [inline] __do_ ---truncated---