[syzbot] [net?] KMSAN: uninit-value in ipvlan_queue_xmit (2)

[syzbot <syzbot+42a0dc856239de4de60e@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    f2e367d6ad3b Merge tag 'for-6.8/dm-fix-3' of git://git.ker..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=144a8d4a180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1b015d567058472
dashboard link: https://syzkaller.appspot.com/bug?extid=42a0dc856239de4de60e
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=149caa54180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10bb8e22180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0dabc03369d1/disk-f2e367d6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/240ca250d398/vmlinux-f2e367d6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cc38bcdb48c9/bzImage-f2e367d6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+42a0dc856239de4de60e@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:524 [inline]
BUG: KMSAN: uninit-value in ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
BUG: KMSAN: uninit-value in ipvlan_queue_xmit+0xf44/0x16b0 drivers/net/ipvlan/ipvlan_core.c:668
 ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:524 [inline]
 ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
 ipvlan_queue_xmit+0xf44/0x16b0 drivers/net/ipvlan/ipvlan_core.c:668
 ipvlan_start_xmit+0x5c/0x1a0 drivers/net/ipvlan/ipvlan_main.c:222
 __netdev_start_xmit include/linux/netdevice.h:4989 [inline]
 netdev_start_xmit include/linux/netdevice.h:5003 [inline]
 xmit_one net/core/dev.c:3547 [inline]
 dev_hard_start_xmit+0x244/0xa10 net/core/dev.c:3563
 __dev_queue_xmit+0x33ed/0x51c0 net/core/dev.c:4351
 dev_queue_xmit include/linux/netdevice.h:3171 [inline]
 packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3081 [inline]
 packet_sendmsg+0x8aef/0x9f10 net/packet/af_packet.c:3113
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x735/0xa10 net/socket.c:2191
 __do_sys_sendto net/socket.c:2203 [inline]
 __se_sys_sendto net/socket.c:2199 [inline]
 __x64_sys_sendto+0x125/0x1c0 net/socket.c:2199
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3819 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 __do_kmalloc_node mm/slub.c:3980 [inline]
 __kmalloc_node_track_caller+0x705/0x1000 mm/slub.c:4001
 kmalloc_reserve+0x249/0x4a0 net/core/skbuff.c:582
 __alloc_skb+0x352/0x790 net/core/skbuff.c:651
 skb_segment+0x20aa/0x7080 net/core/skbuff.c:4647
 udp6_ufo_fragment+0xcab/0x1150 net/ipv6/udp_offload.c:109
 ipv6_gso_segment+0x14be/0x2ca0 net/ipv6/ip6_offload.c:152
 skb_mac_gso_segment+0x3e8/0x760 net/core/gso.c:53
 nsh_gso_segment+0x6f4/0xf70 net/nsh/nsh.c:108
 skb_mac_gso_segment+0x3e8/0x760 net/core/gso.c:53
 __skb_gso_segment+0x4b0/0x730 net/core/gso.c:124
 skb_gso_segment include/net/gso.h:83 [inline]
 validate_xmit_skb+0x107f/0x1930 net/core/dev.c:3628
 __dev_queue_xmit+0x1f28/0x51c0 net/core/dev.c:4343
 dev_queue_xmit include/linux/netdevice.h:3171 [inline]
 packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3081 [inline]
 packet_sendmsg+0x8aef/0x9f10 net/packet/af_packet.c:3113
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x735/0xa10 net/socket.c:2191
 __do_sys_sendto net/socket.c:2203 [inline]
 __se_sys_sendto net/socket.c:2199 [inline]
 __x64_sys_sendto+0x125/0x1c0 net/socket.c:2199
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 5101 Comm: syz-executor421 Not tainted 6.8.0-rc5-syzkaller-00297-gf2e367d6ad3b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
=====================================================


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