Re: [PATCH 2/2] module: add support to avoid duplicates early on load

From: Dan Williams
Date: Tue May 30 2023 - 18:45:39 EST

Linus Torvalds wrote:
> On Mon, May 29, 2023 at 11:18 AM Johan Hovold <johan@xxxxxxxxxx> wrote:
> >
> > I took a closer look at some of the modules that failed to load and
> > noticed a pattern in that they have dependencies that are needed by more
> > than one device.
> Ok, this is a "maybe something like this" RFC series of two patches -
> one trivial one to re-organize things a bit so that we can then do the
> real one which uses a filter based on the inode pointer to return an
> "idempotent return value" for module loads that share the same inode.
> It's entirely untested, and since I'm on the road I'm going to not
> really be able to test it. It compiles for me, and the code looks
> fairly straightforward, but it's probably buggy.

At least for me, these 2 patches, plus Johan's spinlock fixup, are:

Tested-by: Dan Williams <dan.j.williams@xxxxxxxxx>

...on the test that was previously broken on plain v6.4-rc4. I have
these cherry picked on top of v6.4-rc4:

Revert "module: error out early on concurrent load of the same module file"
module: split up 'finit_module()' into init_module_from_file() helper
modules: catch concurrent module loads, take two