On Mon 2025-10-13 10:30:19, Song Liu wrote:
> When there is only one function of the same name, old_sympos of 0 and 1
> are logically identical. Match them in klp_find_func().
>
> This is to avoid a corner case with different toolchain behavior.
>
> In this specific issue, issue two versions of kpatch-build were used to
s/issue, issue/issue/
> build livepatch for the same kernel. One assigns old_sympos == 0 for
> unique local functions, the other assigns old_sympos == 1 for unique
> local functions. Both versions work fine by themselves. (PS: This
> behavior change was introduced in a downstream version of kpatch-build.
> This change does not exist in upstream kpatch-build.)
>
> However, during livepatch upgrade (with the replace flag set) from a
> patch built with one version of kpatch-build to the same fix built with
> the other version of kpatch-build, livepatching fails with errors like:
>
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -88,8 +88,14 @@ static struct klp_func *klp_find_func(struct klp_object
> *obj,
> struct klp_func *func;
>
> klp_for_each_func(obj, func) {
> + /*
> + * Besides identical old_sympos, also condiser old_sympos
As Josh already pointed out:
s/condiser/consider/
> + * of 0 and 1 are identical.
> + */
> if ((strcmp(old_func->old_name, func->old_name) == 0) &&
> - (old_func->old_sympos == func->old_sympos)) {
> + ((old_func->old_sympos == func->old_sympos) ||
> + (old_func->old_sympos == 0 && func->old_sympos == 1) ||
> + (old_func->old_sympos == 1 && func->old_sympos == 0))) {
> return func;
> }
> }
With the two above fixes:
Reviewed-by: Petr Mladek <[email protected]>
Tested-by: Petr Mladek <[email protected]>
I have fixed both problems when committing.
And the patch has been committed into livepatching.git,
branch for-6.19/trivial.
Best Regards,
Petr
