[Intel-gfx] NULL ptr dereference in i915_gem_alloc_object()

[Linus Torvalds]

Testing running out of file descriptors shows a NULL pointer
dereference in i915_gem_alloc_object() because base.filp ends up being
NULL. So the line

    mapping = file_inode(obj->base.filp)->i_mapping;

will cause an oops. The call chain is

SyS_ioctl ->
  do_vfs_ioctl ->
    drm_ioctl ->
      i915_gem_create_ioctl ->
        i915_gem_create ->
          i915_gem_alloc_object

Now, some functions do test "base.filp" for NULL (see for example
i915_gem_pread_ioctl()) so clearly people know that the filp may not
exist. But that path does not.

Comments? Patches even?

              Linus