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

[Kuniyuki Iwashima <kuniyu@amazon.com>]

From: Eric Dumazet <edumazet@google.com>
Date: Thu, 18 Apr 2024 09:19:20 +0200
> On Thu, Apr 18, 2024 at 9:05 AM syzbot
> <syzbot+42a0dc856239de4de60e@syzkaller.appspotmail.com> wrote:
> >
> > 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
> > =====================================================
> >
> >
> > ---
> > This report is generated by a bot. It may contain errors.
> > See https://goo.gl/tpsmEJ for more information about syzbot.
> > syzbot engineers can be reached at syzkaller@googlegroups.com.
> >
> > syzbot will keep track of this issue. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> >
> > If the report is already addressed, let syzbot know by replying with:
> > #syz fix: exact-commit-title
> >
> > If you want syzbot to run the reproducer, reply with:
> > #syz test: git://repo/address.git branch-or-commit-hash
> > If you attach or paste a git patch, syzbot will apply it before testing.
> >
> > If you want to overwrite report's subsystems, reply with:
> > #syz set subsystems: new-subsystem
> > (See the list of subsystem names on the web dashboard)
> >
> > If the report is a duplicate of another one, reply with:
> > #syz dup: exact-subject-of-another-report
> >
> > If you want to undo deduplication, reply with:
> > #syz undup
> 
> Cc Kuniyuki Iwashima
> 
> This is the syzbot bug I mentioned earlier to you.

Will look into it.

Thanks!