Linux kernel module support

This is an informal wiki to keep tabs on Linux kernel module support ongoing R&D and outstanding things.

Previous pull requests

This contains the list of changes sent to Linus. Although each pull request has its own documented set of changes we list a few highlights for each half of each year below. You can inspect these yourself using git log --merges  --grep="Pull modules".

2023

2023-07 - 2023-12

Christoph Hellwig's symbol_get() fix which points to that we should remove those hacks and remove that call. symbol_get() is just a hack to address things which should be fixed through Kconfig at build time as was done in the later patches, and so ultimately it should just be removed.

• modules-v6.7-rc1 - 2023-11-01

• modules-v6.6-rc1 - 2023-08-29

• modules-v6.5-rc1 - 2023-06-28

• modules-6.4-rc5-second-pull - 2023-06-01

2023-01 - 2023-06

Song Liu added a new struct module_memory replacement. Nick Alcock's removed MODULE_LICENSE() from non-modules. We proved vmalloc memory allocation abuse comes from systemd udev, we're wasting ~463 MiB per CPU lost prior to the first fix. After working with Linus on this he came up with a brilliant simple solution making duplicate requests idempotent.

• modules-6.4-rc5-fixes-v2 - 2023-06-01

• modules-6.4-rc5-fixes - 2023-05-30

• modules-6.4-rc4 - 2023-05-03

• modules-6.4-rc1-v2 - 2023-05-03

• modules-v6-4-rc1 - 2023-04-27

• modules-v6.3-rc1 - 2023-02-23

2022

2022-07 - 2022-12

Implication of misalignment of some sections were discussed, for .altinstructions and __bug_table sections, there should be no real ill effects unless you have a buggy exception handler and we ran into one on parisc. Stephen Boyd added zstd in-kernel decompression support but the only users of this would be folks using the load-pin LSM because otherwise we do module decompression in userspace.

• modules-v6.2-rc1| - 2022-12-13

• modules-v6.1-rc1 - 2022-10-10

• modules-v6.0-rc1 - 2022-08-08

2022-01 - 2022-06

Luis starts maintaining as of the v5.17-rc1 pull request. The first order of business was to split up kernel/module.c into parts the modules-v5.17-rc1 merge request was the last one with the modules code all in one place. Aaron Tomlin did all the work, he also added CONFIG_MODULE_UNLOAD_TAINT_TRACKING. Christophe Leroy added CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC which lets architectures to request having modules data in vmalloc area instead of module area.

• modules-v5.19-rc1 - 2022-05-26

• modules-v5.17-rc1 - 2022-01-17

2021

2021-07 - 2021-12

Jessica Yu is maintainer.

• modules-v5.14-rc1 - 2021-07-07

2021-01 - 2021-06

• modules-v5.13-rc1 - 2021-04-30

2020

2020-07 - 2020-12

• modules-v5.11-rc1 - 2020-12-17

• modules-v5.10-rc1 - 2020-10-22

• modules-v5.9-rc1 - 2020-08-14

2020-01 - 2023-06

• modules-v5.8-rc1 - 2020-06-05

• modules-v5.7-rc1 - 2020-04-09

• modules-v5.6-rc1 - 2020-01-31

Ongoing development

Things requiring more community eyeballs or maintainer review:

• execmem_alloc() work to generalize bpf_prog_pack()
• Rust patches for modules

TODO

Things which the maintainer or other developers can work on:

• Add support for EXPORT_SYMBOL_FOR() to force restricting access to symbols only for certain modules

• extend kdevops modules test to include kmod.git userspace tests
• extend kdevops modules test to include the new stress-ng module stressor support
• extend patchwork support to use kdevopes testing using all tests supported for incoming patches by certain developers, leverage the work eBPF folks have done
• hookup kdevops modules testing with 0-day