Re: [syzbot] WARNING in u32_change

[Jamal Hadi Salim]

Is there a way to tell the boat "looking into it?"

cheers,
jamal

On Sun, Sep 25, 2022 at 7:50 AM syzbot
<syzbot+a2c4601efc75848ba321@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    483fed3b5dc8 Add linux-next specific files for 20220921
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=16becbd5080000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=849cb9f70f15b1ba
> dashboard link: https://syzkaller.appspot.com/bug?extid=a2c4601efc75848ba321
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13bc196f080000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=152b15f8880000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/1cb3f4618323/disk-483fed3b.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/cc02cb30b495/vmlinux-483fed3b.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+a2c4601efc75848ba321@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> ------------[ cut here ]------------
> memcpy: detected field-spanning write (size 80) of single field "&n->sel" at net/sched/cls_u32.c:1043 (size 16)
> WARNING: CPU: 0 PID: 3608 at net/sched/cls_u32.c:1043 u32_change+0x2962/0x3250 net/sched/cls_u32.c:1043
> Modules linked in:
> CPU: 0 PID: 3608 Comm: syz-executor971 Not tainted 6.0.0-rc6-next-20220921-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2022
> RIP: 0010:u32_change+0x2962/0x3250 net/sched/cls_u32.c:1043
> Code: f4 df 14 fa 48 8b b5 78 fe ff ff b9 10 00 00 00 48 c7 c2 20 f7 f5 8a 48 c7 c7 a0 f6 f5 8a c6 05 55 b3 63 06 01 e8 db d6 df 01 <0f> 0b e9 73 f3 ff ff e8 c2 df 14 fa 48 c7 c7 00 fc f5 8a e8 66 ed
> RSP: 0018:ffffc90003d7f300 EFLAGS: 00010282
> RAX: 0000000000000000 RBX: ffffc90003d7f618 RCX: 0000000000000000
> RDX: ffff8880235f1d40 RSI: ffffffff81620348 RDI: fffff520007afe52
> RBP: ffffc90003d7f4a0 R08: 0000000000000005 R09: 0000000000000000
> R10: 0000000080000000 R11: 203a7970636d656d R12: ffff888021d420e0
> R13: ffffc90003d7f5b8 R14: ffff888021d43c30 R15: ffff888021d42000
> FS:  0000555555f71300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000000064a110 CR3: 000000002824c000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  tc_new_tfilter+0x938/0x2190 net/sched/cls_api.c:2146
>  rtnetlink_rcv_msg+0x955/0xca0 net/core/rtnetlink.c:6082
>  netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2540
>  netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
>  netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345
>  netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921
>  sock_sendmsg_nosec net/socket.c:714 [inline]
>  sock_sendmsg+0xcf/0x120 net/socket.c:734
>  ____sys_sendmsg+0x712/0x8c0 net/socket.c:2482
>  ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536
>  __sys_sendmsg+0xf3/0x1c0 net/socket.c:2565
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f97a4bf4e69
> Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffdcaf10028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f97a4bf4e69
> RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000006
> RBP: 00007f97a4bb9010 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f97a4bb90a0
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>  </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.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches