[v6.1] kernel BUG in pskb_expand_head (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1989cd3d56e2 Linux 6.1.167
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=111186ba580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=7db97d3b3ca78574a65c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/edd05d4d1a68/disk-1989cd3d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bdc3181e838d/vmlinux-1989cd3d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a78aef5a3a25/Image-1989cd3d.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7db97d...@syzkaller.appspotmail.com

bond1: (slave gre1): Setting fail_over_mac to active for active-backup mode
bond1: (slave gre1): making interface the new active one
device gre1 entered promiscuous mode
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:1839!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 5442 Comm: syz.3.332 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : pskb_expand_head+0xfd4/0x1030 net/core/skbuff.c:1839
lr : pskb_expand_head+0xfd4/0x1030 net/core/skbuff.c:1839
sp : ffff800020f46580
x29: ffff800020f465e0 x28: 00000000000000c0 x27: 0000000000000000
x26: dfff800000000000 x25: 0000000000000a20 x24: 52e28000106a5e5c
x23: ffff0000c41c8000 x22: ffff0000d7f0d028 x21: 00000000ffff7fe0
x20: ffff0000e00d520c x19: ffff0000e00d5140 x18: ffff800011b9bf60
x17: ffff80001835a000 x16: ffff8000082d92bc x15: ffff80000fd49dec
x14: 0000000000000001 x13: 1fffe0001ece201c x12: 0000000000080000
x11: 000000000007ffff x10: ffff800029fef000 x9 : ffff80000fd78928
x8 : 0000000000080000 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000018 x4 : ffff0000d7f0d028 x3 : 0000000000000a20
x2 : 0000000000000000 x1 : 00000000ffff7fe0 x0 : 0000000000000000
Call trace:
pskb_expand_head+0xfd4/0x1030 net/core/skbuff.c:1839
ipgre_header+0xd8/0x4bc net/ipv4/ip_gre.c:863
dev_hard_header include/linux/netdevice.h:3103 [inline]
arp_create+0x2b8/0x7ec net/ipv4/arp.c:577
arp_send_dst net/ipv4/arp.c:314 [inline]
arp_send+0xa8/0x11c net/ipv4/arp.c:328
inetdev_send_gratuitous_arp net/ipv4/devinet.c:1528 [inline]
inetdev_event+0xdb0/0x12d8 net/ipv4/devinet.c:1598
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
call_netdevice_notifiers_info net/core/dev.c:2014 [inline]
call_netdevice_notifiers_extack net/core/dev.c:2052 [inline]
call_netdevice_notifiers+0x110/0x198 net/core/dev.c:2066
bond_change_active_slave+0x1ef8/0x2fa0 drivers/net/bonding/bond_main.c:-1
bond_select_active_slave+0x724/0xa78 drivers/net/bonding/bond_main.c:1314
bond_enslave+0x1e08/0x3178 drivers/net/bonding/bond_main.c:2255
do_set_master net/core/rtnetlink.c:2630 [inline]
rtnl_newlink_create net/core/rtnetlink.c:3439 [inline]
__rtnl_newlink net/core/rtnetlink.c:3642 [inline]
rtnl_newlink+0x175c/0x1a50 net/core/rtnetlink.c:3655
rtnetlink_rcv_msg+0x698/0xcdc net/core/rtnetlink.c:6150
netlink_rcv_skb+0x218/0x3e8 net/netlink/af_netlink.c:2511
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6168
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x60c/0x814 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x6f4/0x9c0 net/netlink/af_netlink.c:1872
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
____sys_sendmsg+0x5c8/0x938 net/socket.c:2518
___sys_sendmsg net/socket.c:2572 [inline]
__sys_sendmsg+0x288/0x374 net/socket.c:2601
__do_sys_sendmsg net/socket.c:2610 [inline]
__se_sys_sendmsg net/socket.c:2608 [inline]
__arm64_sys_sendmsg+0x80/0x94 net/socket.c:2608
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: aa1c03e0 962912b5 d4210000 961ccb1d (d4210000)
---[ end trace 0000000000000000 ]---


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