Re: [syzbot] WARNING in u32_change

[Dmitry Vyukov]

On Sun, 25 Sept 2022 at 17:38, Jamal Hadi Salim <jhs@xxxxxxxxxxxx> wrote:
>
> Is there a way to tell the boat "looking into it?"

Hi Jamal,

No, there is no way.
How do you propose the bot use that information? If it won't use it,
then there is no point in telling it.

Though, it makes sense to tell this to other people. But for that I
guess you just leave a note on the email thread.


> 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
>
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