Re: [patch v2 08/11] futex: Add robust futex unlock IP range

[Thomas Gleixner]

On Fri, Mar 20 2026 at 10:07, Peter Zijlstra wrote:

> On Fri, Mar 20, 2026 at 12:24:46AM +0100, Thomas Gleixner wrote:
>>  /**
>> + * struct futex_unlock_cs_range - Range for the VDSO unlock critical section
>> + * @start_ip:	The start IP of the robust futex unlock critical section (inclusive)
>> + * @end_ip:	The end IP of the robust futex unlock critical section (exclusive)
>> + * @pop_size32:	Pending OP pointer size indicator. 0 == 64-bit, 1 == 32-bit
>> + */
>> +struct futex_unlock_cs_range {
>> +	unsigned long	       start_ip;
>> +	unsigned long	       end_ip;
>> +	unsigned int	       pop_size32;
>> +};
>> +
>> +#define FUTEX_ROBUST_MAX_CS_RANGES	2
>
> Would it make sense to write that like:
>
> #define FUTEX_ROBUST_MAX_CS_RANGE (1+IS_ENABLED(CONFIG_COMPAT))
>
> Given you only ever use that second entry when COMPAT?

Indeed!