Re: [PATCHv4 17/28] x86/vdso: Switch image on setns()/unshare()/clone()

On 6/14/19 3:05 PM, Thomas Gleixner wrote:

On Wed, 12 Jun 2019, Dmitry Safonov wrote:

quoted

 
+#ifdef CONFIG_TIME_NS
+int vdso_join_timens(struct task_struct *task)
+{
+	struct mm_struct *mm = task->mm;
+	struct vm_area_struct *vma;
+
+	if (down_write_killable(&mm->mmap_sem))
+		return -EINTR;
+
+	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+		unsigned long size = vma->vm_end - vma->vm_start;
+
+		if (vma_is_special_mapping(vma, &vvar_mapping) ||
+		    vma_is_special_mapping(vma, &vdso_mapping))
+			zap_page_range(vma, vma->vm_start, size);
+	}
+
+	up_write(&mm->mmap_sem);
+	return 0;
+}
+#else /* CONFIG_TIME_NS */
+int vdso_join_timens(struct task_struct *task)
+{
+	return -ENXIO;
+}

Is that else path really required? The callsite is only compiled when
CONFIG_TIME_NS is enabled, right?

Oh, yes - will drop this.

Thanks,
          Dmitry