[syzbot] [kernel?] net-next test error: UBSAN: array-index-out-of-bounds in alloc_pid

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3a8a670eeeaa Merge tag 'net-next-6.5' of git://git.kernel...
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1391a15f280000
kernel config: https://syzkaller.appspot.com/x/.config?x=924167e3666ff54c
dashboard link: https://syzkaller.appspot.com/bug?extid=f02ef87ef8bbb97026bd
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/580f71d6d107/disk-3a8a670e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7d94a5879cd1/vmlinux-3a8a670e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4ef3ba2a581e/bzImage-3a8a670e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f02ef8...@syzkaller.appspotmail.com

================================================================================
UBSAN: array-index-out-of-bounds in kernel/pid.c:244:15
index 1 is out of range for type 'upid [1]'
CPU: 0 PID: 5002 Comm: syz-executor.0 Not tainted 6.4.0-syzkaller-04247-g3a8a670eeeaa #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
ubsan_epilogue lib/ubsan.c:217 [inline]
__ubsan_handle_out_of_bounds+0xd5/0x140 lib/ubsan.c:348
alloc_pid+0xbe5/0xdd0 kernel/pid.c:244
copy_process+0x4589/0x7620 kernel/fork.c:2519
kernel_clone+0xeb/0x890 kernel/fork.c:2911
__do_sys_clone+0xba/0x100 kernel/fork.c:3054
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f8d13e89fab
Code: ed 0f 85 60 01 00 00 64 4c 8b 0c 25 10 00 00 00 45 31 c0 4d 8d 91 d0 02 00 00 31 d2 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 89 00 00 00 41 89 c5 85 c0 0f 85 90 00 00
RSP: 002b:00007ffd13d711a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffd13d717f8 RCX: 00007f8d13e89fab
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000000 R08: 0000000000000000 R09: 00005555557cb400
R10: 00005555557cb6d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd13d71290 R14: 00007f8d13fac9d8 R15: 000000000000000c
</TASK>
================================================================================


---
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[Christian Brauner]

On Sun, Jul 02, 2023 at 10:35:50PM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 3a8a670eeeaa Merge tag 'net-next-6.5' of git://git.kernel...
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1391a15f280000
> kernel config: https://syzkaller.appspot.com/x/.config?x=924167e3666ff54c
> dashboard link: https://syzkaller.appspot.com/bug?extid=f02ef87ef8bbb97026bd
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/580f71d6d107/disk-3a8a670e.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/7d94a5879cd1/vmlinux-3a8a670e.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/4ef3ba2a581e/bzImage-3a8a670e.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+f02ef8...@syzkaller.appspotmail.com

#syz fix: pid: Replace struct pid 1-element array with flex-array

[Christian Brauner]

On Sun, Jul 02, 2023 at 10:35:50PM -0700, syzbot wrote:

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 3a8a670eeeaa Merge tag 'net-next-6.5' of git://git.kernel...
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1391a15f280000
> kernel config: https://syzkaller.appspot.com/x/.config?x=924167e3666ff54c
> dashboard link: https://syzkaller.appspot.com/bug?extid=f02ef87ef8bbb97026bd
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/580f71d6d107/disk-3a8a670e.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/7d94a5879cd1/vmlinux-3a8a670e.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/4ef3ba2a581e/bzImage-3a8a670e.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+f02ef8...@syzkaller.appspotmail.com