[Ubuntu 22.04.4/linux-image-6.5.0-26-generic] Kernel output "UBSAN: array-index-out-of-bounds in /build/linux-hwe-6.5-34pCLi/linux-hwe-6.5-6.5.0/drivers/net/hyperv/netvsc.c:1445:41" multiple times, especially during boot.

[Akira Tanaka]

Overview:

A newly installed Ubuntu Server 22.04.4 on a Hyper-V virtual machine outputs error message "UBSAN: array-index-out-of-bounds in /build/linux-hwe-6.5-34pCLi/linux-hwe-6.5-6.5.0/drivers/net/hyperv/netvsc.c:1446:41" multiple times, especially during boot.

Reproducing steps:
1. Download ubuntu-22.04.4-live-server-amd64.iso
2. Create a Hyper-V virtual machine.
3. Install Ubuntu 22.04.4 Server on the VM with the downloaded iso normally.
4. Boot the machine.

Additional Information:
- Host machine: Windows 10 Pro 22H2 OS Build 19045.3758
- Hyper-V configuration version: 9.0
- The error message "UBSAN: array-index-out-of-bounds" is similar to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2008157, but the drivers are different.

[GuoqingJiang (guoqingjiang)]

I think it was fixed by upstream commit bb9b0e46b84c ("hv: hyperv.h: Replace one-element array with flexible-array member"), need to double check.

[GuoqingJiang (guoqingjiang)]

[Impact]
error message "UBSAN: array-index-out-of-bounds in drivers/net/hyperv/netvsc.c:1446:41" appears
multiple times during boot for a Hyper-V environment.

[Fix]
Clean cherry-pick commit bb9b0e46b84 for Focal, Jammy and Mantic.

[Test case]
check the dmesg to see if there is the error message "UBSAN: array-index-out-of-bounds"

[Regression Potential]
DPDK which processes netvsc packets, so it might incompatible with ancient DPDK, but modern DPDK
had already used flexible array member.

[Tim Gardner (timg-tpi)]

Patch submitted for review: https://lists.ubuntu.com/archives/kernel-team/2024-April/149922.html

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux/5.15.0-111.121 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux' to 'verification-done-jammy-linux'. If the problem still exists, change the tag 'verification-needed-jammy-linux' to 'verification-failed-jammy-linux'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux/5.4.0-186.206 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal-linux' to 'verification-done-focal-linux'. If the problem still exists, change the tag 'verification-needed-focal-linux' to 'verification-failed-focal-linux'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!