Re: [syzbot] WARNING in btf_type_id_size

Aleksandr Nogikh
2022-10-17T18:30:25Z

On Mon, Oct 17, 2022 at 10:43 AM <sdf@google.com> wrote:
>
> On 10/17, Aleksandr Nogikh wrote:
> > Let's tell the bot about the fix
>
> > #syz fix: bpf: prevent decl_tag from being referenced in func_proto
>
> Thx! Wasn't sure syzkaller would accept that until the fix is actually
> pulled in.

No, that's not strictly necessary :) syzbot accepts fix commit titles
at any moment and then just waits until the commit reaches all
branches it fuzzes.

>
> > On Mon, Oct 17, 2022 at 9:16 AM 'Stanislav Fomichev' via
> > syzkaller-bugs <syzkaller-bugs@googlegroups.com> wrote:
> > >
> > > On Sat, Oct 15, 2022 at 11:52 PM syzbot
> > > <syzbot+6280ebbcdba3e0c14fde@syzkaller.appspotmail.com> wrote:
> > > >
> > > > Hello,
> > > >
> > > > syzbot found the following issue on:
> > > >
> > > > HEAD commit: 0326074ff465 Merge tag 'net-next-6.1' of
> > git://git.kernel...
> > > > git tree: bpf
> > > > console+strace:
> > https://syzkaller.appspot.com/x/log.txt?x=1376ba52880000
> > > > kernel config:
> > https://syzkaller.appspot.com/x/.config?x=796b7c2847a6866a
> > > > dashboard link:
> > https://syzkaller.appspot.com/bug?extid=6280ebbcdba3e0c14fde
> > > > 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=15e182aa880000
> > > > C reproducer:
> > https://syzkaller.appspot.com/x/repro.c?x=1677bfcc880000
> > > >
> > > > Downloadable assets:
> > > > disk image:
> > https://storage.googleapis.com/syzbot-assets/7cc67ced256d/disk-0326074f.raw.xz
> > > > vmlinux:
> > https://storage.googleapis.com/syzbot-assets/86a7be29267c/vmlinux-0326074f.xz
> > > >
> > > > IMPORTANT: if you fix the issue, please add the following tag to the
> > commit:
> > > > Reported-by: syzbot+6280ebbcdba3e0c14fde@syzkaller.appspotmail.com
> > > >
> > > > ------------[ cut here ]------------
> > > > WARNING: CPU: 0 PID: 3609 at kernel/bpf/btf.c:1946
> > btf_type_id_size+0x2d5/0x9d0 kernel/bpf/btf.c:1946
> > > > Modules linked in:
> > > > CPU: 0 PID: 3609 Comm: syz-executor361 Not tainted
> > 6.0.0-syzkaller-02734-g0326074ff465 #0
> > > > Hardware name: Google Google Compute Engine/Google Compute Engine,
> > BIOS Google 09/22/2022
> > > > RIP: 0010:btf_type_id_size+0x2d5/0x9d0 kernel/bpf/btf.c:1946
> > > > Code: ef e8 7f 8e e4 ff 41 83 ff 0b 77 28 f6 44 24 10 18 75 3f e8 6d
> > 91 e4 ff 44 89 fe bf 0e 00 00 00 e8 20 8e e4 ff e8 5b 91 e4 ff <0f> 0b 45
> > 31 f6 e9 98 02 00 00 41 83 ff 12 74 18 e8 46 91 e4 ff 44
> > > > RSP: 0018:ffffc90003cefb40 EFLAGS: 00010293
> > > > RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
> > > > RDX: ffff8880259c0000 RSI: ffffffff81968415 RDI: 0000000000000005
> > > > RBP: ffff88801270ca00 R08: 0000000000000005 R09: 000000000000000e
> > > > R10: 0000000000000011 R11: 0000000000000000 R12: 0000000000000000
> > > > R13: 0000000000000011 R14: ffff888026ee6424 R15: 0000000000000011
> > > > FS: 000055555641b300(0000) GS:ffff8880b9a00000(0000)
> > knlGS:0000000000000000
> > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > > CR2: 0000000000f2e258 CR3: 000000007110e000 CR4: 00000000003506f0
> > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > > > Call Trace:
> > > > <TASK>
> > > > btf_func_proto_check kernel/bpf/btf.c:4447 [inline]
> > > > btf_check_all_types kernel/bpf/btf.c:4723 [inline]
> > > > btf_parse_type_sec kernel/bpf/btf.c:4752 [inline]
> > > > btf_parse kernel/bpf/btf.c:5026 [inline]
> > > > btf_new_fd+0x1926/0x1e70 kernel/bpf/btf.c:6892
> > > > bpf_btf_load kernel/bpf/syscall.c:4324 [inline]
> > > > __sys_bpf+0xb7d/0x4cf0 kernel/bpf/syscall.c:5010
> > > > __do_sys_bpf kernel/bpf/syscall.c:5069 [inline]
> > > > __se_sys_bpf kernel/bpf/syscall.c:5067 [inline]
> > > > __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:5067
> > > > 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: 0033:0x7f0fbae41c69
> > > > 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:00007ffc8aeb6228 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> > > > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0fbae41c69
> > > > RDX: 0000000000000020 RSI: 0000000020000140 RDI: 0000000000000012
> > > > RBP: 00007f0fbae05e10 R08: 0000000000000000 R09: 0000000000000000
> > > > R10: 00000000ffffffff R11: 0000000000000246 R12: 00007f0fbae05ea0
> > > > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> > > > </TASK>
> > >
> > > Will be addressed by
> > >
> > https://lore.kernel.org/bpf/d1379e3f-a64d-8c27-9b77-f6de085ce498@meta.com/T/#u
> > >
> > >
> > > > ---
> > > > 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.
> > > > syzbot can test patches for this issue, for details see:
> > > > https://goo.gl/tpsmEJ#testing-patches
> > >
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