Re: [PATCH pve-kernel] build: ship Rust artifacts for external modules

[Kent Overstreet <kent.overstreet@linux.dev>]

Late followup, because I only checked yesterday and noticed that the
testing on this patch was a snafu.

(_why_ would you send out a patch that you weren't able to successfully
test end to end yourself? I am still scratching my head on that one).

However - the patch is correct, the screwup was just trying to build
bcachefs with a different rustc than the kernel was built with - proxmox
kernels build with rustc from trixie-backports.

I've tested it end to end, and the patch is good and follows what Ubuntu
is doing:

Linux farm2-kvm 7.0.14-14-pve #1 SMP PREEMPT_DYNAMIC PMX 7.0.14-14 (2026-08-22T15:01Z)
CONFIG_RUSTC_VERSION_TEXT="rustc 1.94.1 (e408947bf 2026-03-25) (built from a source tarball)"

[5.383] bcachefs: loading out-of-tree module taints kernel.
[5.482] bcachefs: bch2_dirent_init() ...
vermagic: 7.0.14-14-pve SMP preempt mod_unload modversions

[5.574] starting version need_discard_by_journal_seq (1.38)
[5.574]   Rust support enabled
[5.575] bcachefs (vdb): initializing new filesystem
[5.578] bcachefs (vdb): going read-write
        ... 64M O_DIRECT write, umount, remount, sha1sum -c OK, fsck clean
========= PASSED pve_module in 2s
TEST SUCCESS

As a reminder, every other distro is either shipping the Rust build
artifacts or supports reproducible kernel builds; this patch is
necessary for bcachefs to continue supporting Proxmox.

Cheers,
Kent