Greetings, Benjamin!

It appears that kmod added support for arbitrary symbol lengths in
[commit 2213612](https://github.com/kmod-
project/kmod/commit/2213612e19ea64d86a424b2dc51182ea3633b7b2) which
landed in [v34](https://github.com/kmod-project/kmod/releases/tag/v34)
last month, but I do not know if it supports this exact method of
declaring symbol length. I have not tested any versions of kmod other
than what was included in either 22.04 (v29) or 24.04 (v31).

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https://bugs.launchpad.net/bugs/2100957

Title:
  Noble kernel breaks `modprobe --dump-modversion`

Status in linux package in Ubuntu:
  Triaged

Bug description:
  The following patch was introduced into Noble's kernel ( which is said
  to allow support for arbitrary symbol length in modversion:
  https://git.launchpad.net/~ubuntu-
  
kernel/ubuntu/+source/linux/+git/noble/commit/scripts/mod/modpost.c?id=0a4e704ad1a9800a7d24179c9d14aae6f43c4813

  Noble, however, contains kmod v31:

  $ modprobe -V
  kmod version 31
  -ZSTD -XZ -ZLIB -LIBCRYPTO -EXPERIMENTAL

  This version of kmod expects that modversion symbol lengths be of size
  64. This means that any module compiled on Noble will fail `modprobe
  --dump-modversion`.

  To reproduce this error, one can build a simple module such as the
  following on both Noble and Jammy (which does not contain this bug)
  [note: this repo does not contain a `MODULE_LICENSE()` line so add
  that to `hello.c` before building]: https://github.com/jmuia/hello-ko

  We will call the module built on Noble `hello-noble.ko` and the module
  built on Jammy `hello-jammy.ko`.

  Noble (6.8.0-54-generic):

  $ modprobe --dump-modversion hello-jammy.ko
  0x09931d80      module_layout
  0x92997ed8      _printk

  $ modprobe --dump-modversion hello-noble.ko
  modprobe: FATAL: could not get modversions of hello-noble.ko: Invalid argument

  Jammy (5.15.0-134-generic):

  $ modprobe --dump-modversion hello-jammy.ko
  0x09931d80      module_layout
  0x92997ed8      _printk

  $ modprobe --dump-modversion hello-noble.ko
  modprobe: FATAL: could not get modversions of hello-noble.ko: Invalid argument

  We expect that the error from `modprobe --dump-modversion hello-
  noble.ko` should not happen on either Noble or Jammy.

  This bug was discovered by myself and @jmbl while trying to utilize
  `kpatch-build` as we experienced different behavior when building on
  Jammy and Noble.

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