Re: [RFC PATCH 2/6] testing/pkeys: Don't use uninitialized variable

[Sohil Mehta]

On 6/10/2022 4:35 PM, ira.weiny@xxxxxxxxx wrote:
> diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
> index d0183c381859..43e47de19c0d 100644
> --- a/tools/testing/selftests/vm/protection_keys.c
> +++ b/tools/testing/selftests/vm/protection_keys.c
> @@ -1225,9 +1225,9 @@ void test_pkey_alloc_exhaust(int *ptr, u16 pkey)
>   		int new_pkey;
>   		dprintf1("%s() alloc loop: %d\n", __func__, i);
>   		new_pkey = alloc_pkey();
> -		dprintf4("%s()::%d, err: %d pkey_reg: 0x%016llx"
> +		dprintf4("%s()::%d, errno: %d pkey_reg: 0x%016llx"

What is errno referring to over here? There are a few things happening 
in alloc_pkey(). I guess it would show the latest error that happened. 
Does errno need to be set to 0 before the call?

Also, would it be useful to print the return value (new_pkey) from 
alloc_pkey() here?

>   				" shadow: 0x%016llx\n",
> -				__func__, __LINE__, err, __read_pkey_reg(),
> +				__func__, __LINE__, errno, __read_pkey_reg(),
>   				shadow_pkey_reg);
>   		read_pkey_reg(); /* for shadow checking */
>   		dprintf2("%s() errno: %d ENOSPC: %d\n", __func__, errno, ENOSPC);

Sohil