Re: [PATCH 2/4] selftest/arm64: Treat KSM merge_across_nodes as optional

[Muhammad Usama Anjum <usama.anjum@arm.com>]

On 20/08/2026 5:09 pm, Mark Brown wrote:
> On Thu, Aug 20, 2026 at 04:33:24PM +0100, Muhammad Usama Anjum wrote:
>> The MTE KSM test unconditionally saves, enables and restores the
>> merge_across_nodes sysfs attribute. The kernel only creates this
>> attribute when CONFIG_NUMA=y. A non-NUMA kernel consequently prints the
>> following message three times even though all KSM subtests pass:
> 
>>  static void mte_ksm_setup(void)
>>  {
>> -	ksm_sysfs[0] = read_sysfs(PATH_KSM "merge_across_nodes");
>> -	write_sysfs(PATH_KSM "merge_across_nodes", 1);
>> +	has_merge_across_nodes = !access(PATH_KSM "merge_across_nodes", F_OK);
> 
> Don't we need the file to be readable and writable, not just extant?

Correct, I'll fix it.

> Looking quickly at the test I'm actually not spotting where it checks
> that it's running as root which I think it needs in general.

I'll add check for that as well.

-- 
Thanks,
Usama