lkml.org 
[lkml]   [2012]   [Apr]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/2] drm/i915: fix integer overflow in i915_gem_execbuffer2()
From
Date
On Apr 6, 2012, at 3:40 PM, Chris Wilson wrote:
> On Fri, 6 Apr 2012 14:17:41 -0400, Xi Wang <xi.wang@gmail.com> wrote:
>>
>> Why an attempt to vmalloc? The overflow check in drm_malloc_ab()
>> will simply return NULL and fail the ioctl with -ENOMEM.
>
> It's an invalid value for the ioctl and should be treated as such, not
> making ENOMEM more ambiguous.

We could copy and paste the overflow check so as to return -EINVAL.
I just doubt how much that would help --- you can find existing usages
in other functions, for example, in i915_gem_execbuffer():

/* Copy in the exec list from userland */
exec_list = drm_malloc_ab(sizeof(*exec_list), args->buffer_count);
exec2_list = drm_malloc_ab(sizeof(*exec2_list), args->buffer_count);
if (exec_list == NULL || exec2_list == NULL) {
DRM_DEBUG("Failed to allocate exec list for %d buffers\n",
args->buffer_count);
drm_free_large(exec_list);
drm_free_large(exec2_list);
return -ENOMEM;
}

Should we fix all these as well by repeating the checks and returning
-EINVAL? I am worried about the code bloat / readability price you
would pay for getting a different error code.

BTW, I've also seen code using E2BIG. Any documented guideline?

- xi



\
 
 \ /
  Last update: 2012-04-06 22:37    [W:0.040 / U:0.396 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site