Re: [PATCHv5 perf/core 08/22] uprobes/x86: Add mapping for optimized uprobe trampolines

[Oleg Nesterov <oleg@redhat.com>]

On 07/11, Jiri Olsa wrote:
>
> +static unsigned long find_nearest_trampoline(unsigned long vaddr)
> +{
> +	struct vm_unmapped_area_info info = {
> +		.length     = PAGE_SIZE,
> +		.align_mask = ~PAGE_MASK,
> +	};
> +	unsigned long low_limit, high_limit;
> +	unsigned long low_tramp, high_tramp;
> +	unsigned long call_end = vaddr + 5;
> +
> +	if (check_add_overflow(call_end, INT_MIN, &low_limit))
> +		low_limit = PAGE_SIZE;
> +
> +	high_limit = call_end + INT_MAX;
> +
> +	/* Search up from the caller address. */
> +	info.low_limit = call_end;
> +	info.high_limit = min(high_limit, TASK_SIZE);
> +	high_tramp = vm_unmapped_area(&info);
> +
> +	/* Search down from the caller address. */
> +	info.low_limit = max(low_limit, PAGE_SIZE);
> +	info.high_limit = call_end;
> +	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
> +	low_tramp = vm_unmapped_area(&info);
> +
> +	if (IS_ERR_VALUE(high_tramp) && IS_ERR_VALUE(low_tramp))
> +		return -ENOMEM;
> +	if (IS_ERR_VALUE(high_tramp))
> +		return low_tramp;
> +	if (IS_ERR_VALUE(low_tramp))
> +		return high_tramp;
> +
> +	/* Return address that's closest to the caller address. */
> +	if (call_end - low_tramp < high_tramp - call_end)
> +		return low_tramp;
> +	return high_tramp;
> +}

IIUC, nothing else has changed since I've acked the previous version?
Then my ack still stands,

Acked-by: Oleg Nesterov <oleg@redhat.com>