Re: [PATCH v7 3.2-rc2 3/30] uprobes: register/unregister probes.

[Peter Zijlstra]

On Fri, 2011-11-18 at 16:37 +0530, Srikar Dronamraju wrote:
> +static int __register_uprobe(struct inode *inode, loff_t offset,
> +                               struct uprobe *uprobe)
> +{
> +       struct list_head try_list;
> +       struct vm_area_struct *vma;
> +       struct address_space *mapping;
> +       struct vma_info *vi, *tmpvi;
> +       struct mm_struct *mm;
> +       loff_t vaddr;
> +       int ret = 0;
> +
> +       mapping = inode->i_mapping;
> +       INIT_LIST_HEAD(&try_list);
> +       while ((vi = find_next_vma_info(&try_list, offset,
> +                                               mapping, true)) != NULL) {
> +               if (IS_ERR(vi)) {
> +                       ret = -ENOMEM;
> +                       break;
> +               }
> +               mm = vi->mm;
> +               down_read(&mm->mmap_sem);
> +               vma = find_vma(mm, (unsigned long)vi->vaddr);
> +               if (!vma || !valid_vma(vma, true)) {
> +                       list_del(&vi->probe_list);
> +                       kfree(vi);
> +                       up_read(&mm->mmap_sem);
> +                       mmput(mm);
> +                       continue;
> +               }
> +               vaddr = vma->vm_start + offset;
> +               vaddr -= vma->vm_pgoff << PAGE_SHIFT;
> +               if (vma->vm_file->f_mapping->host != inode ||
> +                                               vaddr != vi->vaddr) {
> +                       list_del(&vi->probe_list);
> +                       kfree(vi);
> +                       up_read(&mm->mmap_sem);
> +                       mmput(mm);
> +                       continue;
> +               }
> +               ret = install_breakpoint(mm);
> +               up_read(&mm->mmap_sem);
> +               mmput(mm);
> +               if (ret && ret == -EEXIST)
> +                       ret = 0;
> +               if (!ret)
> +                       break;

Shouldn't that read:
		if (ret)
			break;

So that we bail when there's a real error instead of no error?

> +       }
> +       list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
> +               list_del(&vi->probe_list);
> +               kfree(vi);
> +       }
> +       return ret;
> +} 
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