Re: [PATCH] livepatch: Fix leak on klp_init_patch_early failure path

From: Josh Poimboeuf
Date: Mon Dec 13 2021 - 22:13:19 EST


On Mon, Dec 13, 2021 at 02:58:38PM -0800, David Vernet wrote:
> > I don't think the fix will be quite that simple. For example, if
> > klp_init_patch_early() fails, that means try_module_get() hasn't been
> > done, so klp_free_patch_finish() will wrongly do a module_put().
>
> Ugh, good point and thank you for catching that. Another problem with the
> current patch is that we'll call kobject_put() on the patch even if we
> never call kobject_init on the patch due to patch->objs being NULL.
>
> Perhaps we should pull try_module_get() and the NULL check for patch->objs
> out of klp_init_patch_early()? It feels a bit more intuitive to me if
> klp_init_patch_early() were only be responsible for initializing kobjects
> for the patch and its objects / funcs anyways.
>
> Testing it locally seems to work fine. Let me know if this sounds
> reasonable to you, and I'll send out a v2 patch with the fixes to both the
> patch description, and logic.

Sounds reasonable to me. Thanks.

--
Josh