[syzbot] WARNING in btf_type_id_size

[syzbot]

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+6280eb...@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>


---
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[Stanislav Fomichev]

Will be addressed by
https://lore.kernel.org/bpf/d1379e3f-a64d-8c27...@meta.com/T/#u

[Aleksandr Nogikh]

Let's tell the bot about the fix

#syz fix: bpf: prevent decl_tag from being referenced in func_proto

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[s...@google.com]

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.

[Aleksandr Nogikh]

On Mon, Oct 17, 2022 at 10:43 AM <s...@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.