[PATCH v13 18/24] selftests/vm: fix an assertion in test_pkey_alloc_exhaust()

[Dave Hansen]

On 06/13/2018 05:45 PM, Ram Pai wrote:
>  	/*
> -	 * There are 16 pkeys supported in hardware.  Three are
> -	 * allocated by the time we get here:
> -	 *   1. The default key (0)
> -	 *   2. One possibly consumed by an execute-only mapping.
> -	 *   3. One allocated by the test code and passed in via
> -	 *      'pkey' to this function.
> -	 * Ensure that we can allocate at least another 13 (16-3).
> +	 * There are NR_PKEYS pkeys supported in hardware. arch_reserved_keys()
> +	 * are reserved. One of which is the default key(0). One can be taken
> +	 * up by an execute-only mapping.
> +	 * Ensure that we can allocate at least the remaining.
>  	 */
> -	pkey_assert(i >= NR_PKEYS-3);
> +	pkey_assert(i >= (NR_PKEYS-arch_reserved_keys()-1));

We recently had a bug here.  I fixed it and left myself a really nice
comment so I and others wouldn't screw it up in the future.

Does this kill my nice, new comment?