On Thu 2015-11-12 10:59:52, Chris J Arges wrote:
> In cases of duplicate symbols, sympos will be used to disambiguate instead
> of val. By default sympos will be 0, and patching will only succeed if
> the symbol is unique. Specifying a positive value will ensure that
> occurrence of the symbol in kallsyms for the patched object will be used
> for patching if it is valid.
>
> Remove klp_verify_callback, klp_verify_args and klp_verify_vmlinux_symbol
> as they are no longer used.
>
> >From the klp_reloc structure remove val, as it can be refactored as a
> local variable in klp_write_object_relocations.
>
> Signed-off-by: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index 4cd079c..071895f 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -275,29 +237,30 @@ static int klp_write_object_relocations(struct module *pmod,
> return -EINVAL;
>
> for (reloc = obj->relocs; reloc->name; reloc++) {
> - if (!klp_is_module(obj)) {
> - ret = klp_verify_vmlinux_symbol(reloc->name,
> - reloc->val);
> - if (ret)
> - return ret;
> - } else {
> - /* module, reloc->val needs to be discovered */
> - if (reloc->external)
> - ret = klp_find_external_symbol(pmod,
> - reloc->name,
> - &reloc->val);
> - else
> - ret = klp_find_object_symbol(obj->mod->name,
> - reloc->name,
> - &reloc->val, 0);
> - if (ret)
> - return ret;
> - }
> + /* discover the address of the referenced symbol */
> + if (reloc->external) {
> + /*
> + * external symbols aren't specified by the user
> + * therefore sympos should not be used
> + */
> + if (reloc->sympos) {
> + pr_err("symbol '%s' is external and has sympos %lu\n",
> + reloc->name, reloc->sympos);
> + return -EINVAL;
> + }
To be precise, reloc->sympos == 1 is a valid value. Note that it will show
"symbol,1" in sysfs. I suggest the following to keep it simple:
if (reloc->sympos && (reloc->sympos != 1)) {
pr_err("relocated external symbols must be unique but '%s' has sympos %lu\n",
reloc->name, reloc->sympos);
return -EINVAL;
}
Then we could even get rid of the comment.
Huh, I am looking forward to get rid of the external symbols ;-)
Thank you,
Petr
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