Hi Matt, On Tue, Aug 6, 2024 at 9:21 PM Matthew Maurer <mmaurer@xxxxxxxxxx> wrote: > > Previously MODVERSIONS + RUST Redux [1] > > This patch series is intended for use alongside the Implement > MODVERSIONS for RUST [2] series as a replacement for the symbol name > hashing approach used there to enable RUST and MODVERSIONS at the same > time. > > Elsewhere, we've seen a desire for long symbol name support for LTO > symbol names [3], and the previous series came up [4] as a possible > solution rather than hashing, which some have objected [5] to. > > This series adds a MODVERSIONS format which uses a section per column. > This avoids userspace tools breaking if we need to make a similar change > to the format in the future - we would do so by adding a new section, > rather than editing the struct definition. In the new format, the name > section is formatted as a concatenated sequence of NUL-terminated > strings, which allows for arbitrary length names. > > Currently, this series emits both the extended format and the current > format on all modules, and prefers the extended format when checking if > present. I'm open to various other policies via Kconfig knobs, but this > seemed like a good initial default. > > The refactor to MODVERSIONS is prefixed to this series as result of an > explicit request [6] by Luis in response to the original patchset. > > If you are testing this patch alongside RUST by manually removing the > !MODVERSIONS restriction (this series doesn't remove it, because the > CRCs don't mean what we'd want them to yet, we need the DWARF patch for > that) and have kernel hardening enabled, you may need the CPU > Mitigations [7] series. Without it, the foo.mod.o file produced by the > C compiler will reference __x86_return_thunk, but foo.o will not. > This means that the version table will not contain a version for > __x86_return_thunk, but foo.ko will reference it, which will result > in a version check failure. Thanks for reviving this series! I tested your patches on top of my DWARF modversions series and it seems to work as expected. I confirmed that Rust modules have versions, the kernel verifies them correctly, loading the modules succeeds, and scripts/export_report.pl seems to produce correct output as well. Here's the tree I used, it includes the prerequisite patch sets you mentioned: https://github.com/samitolvanen/linux/commits/rustmodversions/ With the minor comments I had about patch 14 addressed: Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Tested-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Sami
