releases/4.9.64/drm-sti-sti_vtg-handle-return-null-error-from-devm_ioremap_nocache.patch

   1 From foo@baz Sun Nov 19 11:32:28 CET 2017
   2 From: Arvind Yadav <arvind.yadav.cs@gmail.com>
   3 Date: Wed, 21 Dec 2016 11:00:12 +0530
   4 Subject: drm/sti: sti_vtg: Handle return NULL error from devm_ioremap_nocache
   5
   6 From: Arvind Yadav <arvind.yadav.cs@gmail.com>
   7
   8
   9 [ Upstream commit 1ae0d5af347df224a6e76334683f13a96d915a44 ]
  10
  11 Here, If devm_ioremap_nocache will fail. It will return NULL.
  12 Kernel can run into a NULL-pointer dereference. This error check
  13 will avoid NULL pointer dereference.
  14
  15 Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
  16 Acked-by: Vincent Abriou <vincent.abriou@st.com>
  17 Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  19 ---
  20  drivers/gpu/drm/sti/sti_vtg.c |    4 ++++
  21  1 file changed, 4 insertions(+)
  22
  23 --- a/drivers/gpu/drm/sti/sti_vtg.c
  24 +++ b/drivers/gpu/drm/sti/sti_vtg.c
  25 @@ -429,6 +429,10 @@ static int vtg_probe(struct platform_dev
  26                 return -ENOMEM;
  27         }
  28         vtg->regs = devm_ioremap_nocache(dev, res->start, resource_size(res));
  29 +       if (!vtg->regs) {
  30 +               DRM_ERROR("failed to remap I/O memory\n");
  31 +               return -ENOMEM;
  32 +       }
  33
  34         np = of_parse_phandle(pdev->dev.of_node, "st,slave", 0);
  35         if (np) {