Thread (19 messages) 19 messages, 6 authors, 2021-12-17

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

From: Josh Poimboeuf <hidden>
Date: 2021-12-14 03:13:18
Also in: live-patching, lkml

On Mon, Dec 13, 2021 at 02:58:38PM -0800, David Vernet wrote:
quoted
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
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