Re: [PATCH 4/7] uretprobes: return probe entry, prepare_uretprobe()

[Oleg Nesterov <oleg@redhat.com>]

I'll try to read this series later. Just one note...

On 03/22, Anton Arapov wrote:
>
>    IOW, we must ensure that uprobe_pre_sstep_notifier() can't return 0.

Yes, but I do not see this change?

> +static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
> +{
> +	struct return_instance *ri;
> +	struct uprobe_task *utask;
> +	struct xol_area *area;
> +	unsigned long trampoline_vaddr;
> +	unsigned long prev_ret_vaddr, ret_vaddr;
> +
> +	area = get_xol_area();
> +	if (!area)
> +		return;
> +
> +	utask = get_utask();
> +	if (!utask)
> +		return;
> +
> +	prev_ret_vaddr = -1;
> +	if (utask->return_instances)
> +		prev_ret_vaddr = utask->return_instances->orig_ret_vaddr;
> +
> +	ri = kzalloc(sizeof(struct return_instance), GFP_KERNEL);
> +	if (!ri)
> +		return;
> +
> +	ri->dirty = false;
> +	trampoline_vaddr = get_trampoline_vaddr(area);
> +	ret_vaddr = arch_uretprobe_hijack_return_addr(trampoline_vaddr, regs);

OK, but you need to ensure that this code can be compiled on poweprc.

Oleg.