[SRU][F, J, N, O, P][PATCH 0/1] iBFT iSCSI out-of-bounds shift UBSAN warning

[Agathe Porte]

Hello,

2025-02-11 08:24 CET, Chengen Du:
> BugLink: https://bugs.launchpad.net/bugs/2097824
> 
> SRU Justification:
> 
> [Impact]
> During an iSCSI boot in an IPv6 environment, `iscsistart` continues to access the `/sys/firmware/ibft/ethernetX/subnet-mask` entry, despite subnet masks being irrelevant for IPv6. Since the IPv6 prefix length is 64, this leads to a negative shift exponent, triggering a UBSAN warning.
> 
> [Fix]
> A commit has been made to fix this issue.
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=07e0d99a2f701123ad3104c0f1a1e66bce74d6e5

CONFIG_UBSAN is not enabled for focal:

(focal/linux/linux-main) $ (cd debian.master && git grep CONFIG_UBSAN)
changelog:    - objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings
config/annotations:CONFIG_UBSAN                                    policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
config/annotations:CONFIG_UBSAN_ALIGNMENT                          policy<{'amd64': 'y', 'arm64': 'y', 'armhf': 'y', 'i386': 'y', 'ppc64el': 'y', 's390x': 'y'}>

Do we need to port this to focal? I would say jammy+ is enough.