On 6/22/22 04:48, Pavel Machek wrote:
> Hi!
>
>
>> +static int __init mmio_stale_data_parse_cmdline(char *str)
>> +{
>> + if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA))
>> + return 0;
>> +
>> + if (!str)
>> + return -EINVAL;
>> +
>> + if (!strcmp(str, "off")) {
>> + mmio_mitigation = MMIO_MITIGATION_OFF;
>> + } else if (!strcmp(str, "full")) {
>> + mmio_mitigation = MMIO_MITIGATION_VERW;
>> + } else if (!strcmp(str, "full,nosmt")) {
>> + mmio_mitigation = MMIO_MITIGATION_VERW;
>> + mmio_nosmt = true;
>> + }
>> +
>> + return 0;
>> +}
>
> This is wrong, AFAICT. Returning 0 will pollute init's environment;
> Randy was cleaning those lately and we are even seeing them in
> -stable. See for example b793a01000122d2bd133ba451a76cc135b5e162c.
>
> The early return 0 should disappear, too; we should validate the
> option even on non-buggy machines.
It's good to be on the lookout for such problems, but __setup()
functions (like I was cleaning) are the opposite (sad:( of
early_param() functions, which this one is.
early_param() does return 0 on success and non-zero
on error, so this looks OK to me.
--
~Randy
