[syzbot] [kernel?] net test error: UBSAN: negation-overflow in corrupted

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cc0dec3f659d Merge branch 'net-stmmac-fix-timestamp-snapsh..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=131c21b3980000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac0f76cd0f8e093a
dashboard link: https://syzkaller.appspot.com/bug?extid=76fd07ed2518fb9303f9
compiler: Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1d6f321414b4/disk-cc0dec3f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/072c28c931b0/vmlinux-cc0dec3f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bcb44ff40c55/bzImage-cc0dec3f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+76fd07...@syzkaller.appspotmail.com

virtio-scsi blksize=512 sectors=4194304 = 2048 MiB
drive 0x000f27f0: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Sending Seabios boot VM event.
Booting from Hard Disk 0...
[ 0serialport: Connected to syzkaller.us-central1-c.ci-upstream-net-this-kasan-gce-test-1 port 1 (session ID: e72bd3249fa5f4b40b974e21e6d99e16e8384254f2e85c0fe39918dcc479fa4d, active connections: 1).
.000000][ T0] UBSAN: negation-overflow in lib/sort.c:199:36


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[Aleksandr Nogikh]

+ Kees Cook

Hi Kees,

This boot time error appears on v6.15-rc* when the kernel is built
with clang-20. It's apparently related to

commit ed2b548f1017586c44f50654ef9febb42d491f31
Author: Kees Cook <ke...@kernel.org>
Date: Thu Mar 6 20:19:09 2025 -0800
ubsan/overflow: Rework integer overflow sanitizer option to turn
on everything

Could you please have a look whether it's a legit issue?

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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.