On Wed, Jul 20, 2016 at 05:09:28PM +0100, Marc Zyngier wrote:

+static inline unsigned long min_stack_size(unsigned long addr)
+{
+	unsigned long size;
+	struct kprobe_ctlblk *ctl;
+
+	if (on_irq_stack(addr, raw_smp_processor_id()))
+		size = IRQ_STACK_PTR(raw_smp_processor_id()) - addr;
+	else
+		size = (unsigned long)current_thread_info() + THREAD_START_SP - addr;
+
+	return min(size, sizeof(ctl->jprobes_stack));
+}

We could drop the local ctl pointer:

	return min(size, sizeof(((struct kprobe_ctlblk *)0)->jprobes_stack));

If you add a log, I'll push the patch on top of the kprobes branch.

Thanks.

-- 
Catalin