Re: [syzbot] [net?] WARNING in gre_tap_xmit (2)

[Eric Dumazet]

On Fri, Apr 19, 2024 at 11:39 AM syzbot
<syzbot+c298c9f0e46a3c86332b@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    443574b03387 riscv, bpf: Fix kfunc parameters incompatibil..
> git tree:       bpf
> console output: https://syzkaller.appspot.com/x/log.txt?x=165886c3180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
> dashboard link: https://syzkaller.appspot.com/bug?extid=c298c9f0e46a3c86332b
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/3f355021a085/disk-443574b0.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/44cf4de7472a/vmlinux-443574b0.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/a99a36c7ad65/bzImage-443574b0.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+c298c9f0e46a3c86332b@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 13407 at include/linux/skbuff.h:2740 pskb_may_pull_reason include/linux/skbuff.h:2740 [inline]
> WARNING: CPU: 0 PID: 13407 at include/linux/skbuff.h:2740 pskb_may_pull include/linux/skbuff.h:2756 [inline]
> WARNING: CPU: 0 PID: 13407 at include/linux/skbuff.h:2740 pskb_network_may_pull include/linux/skbuff.h:3077 [inline]
> WARNING: CPU: 0 PID: 13407 at include/linux/skbuff.h:2740 pskb_inet_may_pull include/net/ip_tunnels.h:361 [inline]
> WARNING: CPU: 0 PID: 13407 at include/linux/skbuff.h:2740 gre_tap_xmit+0x4ff/0x6e0 net/ipv4/ip_gre.c:734
> Modules linked in:
> CPU: 0 PID: 13407 Comm: syz-executor.1 Not tainted 6.8.0-syzkaller-05236-g443574b03387 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
> RIP: 0010:pskb_may_pull_reason include/linux/skbuff.h:2740 [inline]
> RIP: 0010:pskb_may_pull include/linux/skbuff.h:2756 [inline]
> RIP: 0010:pskb_network_may_pull include/linux/skbuff.h:3077 [inline]
> RIP: 0010:pskb_inet_may_pull include/net/ip_tunnels.h:361 [inline]
> RIP: 0010:gre_tap_xmit+0x4ff/0x6e0 net/ipv4/ip_gre.c:734
> Code: 00 4c 89 ef 48 89 ee 48 89 da e8 7c 8f fb ff 31 c0 48 83 c4 38 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 62 55 9d f7 90 <0f> 0b 90 e9 09 fc ff ff 44 89 e7 89 ee e8 0f 57 9d f7 41 39 ec 0f
> RSP: 0018:ffffc90004b66e00 EFLAGS: 00010287
> RAX: ffffffff89f79b0e RBX: ffff888061667718 RCX: 0000000000040000
> RDX: ffffc9000c375000 RSI: 00000000000124e0 RDI: 00000000000124e1
> RBP: 00000000ffffffb6 R08: ffffffff89f79712 R09: 1ffffffff1f0d5cd
> R10: dffffc0000000000 R11: ffffffff89f79610 R12: 0000000000000000
> R13: ffff888061667640 R14: ffff888062b64000 R15: dffffc0000000000
> FS:  00007f08d29ff6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020010000 CR3: 0000000061678000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
> Call Trace:
>  <TASK>
>  __netdev_start_xmit include/linux/netdevice.h:4903 [inline]
>  netdev_start_xmit include/linux/netdevice.h:4917 [inline]
>  xmit_one net/core/dev.c:3531 [inline]
>  dev_hard_start_xmit+0x26a/0x790 net/core/dev.c:3547
>  sch_direct_xmit+0x2b6/0x5f0 net/sched/sch_generic.c:343
>  __dev_xmit_skb net/core/dev.c:3760 [inline]
>  __dev_queue_xmit+0x1912/0x3b10 net/core/dev.c:4301
>  bond_start_xmit+0x1389/0x1c40 drivers/net/bonding/bond_main.c:5469
>  __netdev_start_xmit include/linux/netdevice.h:4903 [inline]
>  netdev_start_xmit include/linux/netdevice.h:4917 [inline]
>  xmit_one net/core/dev.c:3531 [inline]
>  dev_hard_start_xmit+0x26a/0x790 net/core/dev.c:3547
>  __dev_queue_xmit+0x19f4/0x3b10 net/core/dev.c:4335
>  packet_snd net/packet/af_packet.c:3083 [inline]
>  packet_sendmsg+0x4932/0x63d0 net/packet/af_packet.c:3115
>  sock_sendmsg_nosec net/socket.c:730 [inline]
>  __sock_sendmsg+0x221/0x270 net/socket.c:745
>  ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
>  ___sys_sendmsg net/socket.c:2638 [inline]
>  __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
>  do_syscall_64+0xfb/0x240
>  entry_SYSCALL_64_after_hwframe+0x6d/0x75
> RIP: 0033:0x7f08d2e7dea9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f08d29ff0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f08d2fabf80 RCX: 00007f08d2e7dea9
> RDX: 00000000200400c4 RSI: 0000000020000180 RDI: 0000000000000006
> RBP: 00007f08d2eca4a4 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 000000000000000b R14: 00007f08d2fabf80 R15: 00007ffcba0da4f8
>  </TASK>
>
>
> ---
> 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@xxxxxxxxxxxxxxxx.
>
> 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 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

Kuniyuki , this is another manifestation of NSH bug, thanks !