On 02/28/2014 10:20 PM, Alexey Khoroshilov wrote:

vmw_takedown_otable_base() and vmw_mob_unbind() check for potential vmw_fifo_reserve() failure and print error message, but then immediately dereference NULL pointer.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov khoroshilov@ispras.ru

drivers/gpu/drm/vmwgfx/vmwgfx_mob.c | 35 +++++++++++++++++++---------------- 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_mob.c b/drivers/gpu/drm/vmwgfx/vmwgfx_mob.c index d4a5a19cb8c3..04a64b8cd3cd 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_mob.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_mob.c @@ -188,18 +188,20 @@ static void vmw_takedown_otable_base(struct vmw_private *dev_priv,

bo = otable->page_table->pt_bo; cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));

• if (unlikely(cmd == NULL))

• DRM_ERROR("Failed reserving FIFO space for OTable setup.\n");
  

• memset(cmd, 0, sizeof(*cmd));
• cmd->header.id = SVGA_3D_CMD_SET_OTABLE_BASE;
• cmd->header.size = sizeof(cmd->body);
• cmd->body.type = type;
• cmd->body.baseAddress = 0;
• cmd->body.sizeInBytes = 0;
• cmd->body.validSizeInBytes = 0;
• cmd->body.ptDepth = SVGA3D_MOBFMT_INVALID;
• vmw_fifo_commit(dev_priv, sizeof(*cmd));

• if (unlikely(cmd == NULL)) {

• DRM_ERROR("Failed reserving FIFO space for OTable "
  

• 	  "takedown.\n");
  

• } else {

• memset(cmd, 0, sizeof(*cmd));
  

• cmd->header.id = SVGA_3D_CMD_SET_OTABLE_BASE;
  

• cmd->header.size = sizeof(cmd->body);
  

• cmd->body.type = type;
  

• cmd->body.baseAddress = 0;
  

• cmd->body.sizeInBytes = 0;
  

• cmd->body.validSizeInBytes = 0;
  

• cmd->body.ptDepth = SVGA3D_MOBFMT_INVALID;
  

• vmw_fifo_commit(dev_priv, sizeof(*cmd));
  

• }

  if (bo) { int ret;

@@ -562,11 +564,12 @@ void vmw_mob_unbind(struct vmw_private *dev_priv, if (unlikely(cmd == NULL)) { DRM_ERROR("Failed reserving FIFO space for Memory " "Object unbinding.\n");

• } else {

• cmd->header.id = SVGA_3D_CMD_DESTROY_GB_MOB;
  

• cmd->header.size = sizeof(cmd->body);
  

• cmd->body.mobid = mob->id;
  

• vmw_fifo_commit(dev_priv, sizeof(*cmd));
  

  }

• cmd->header.id = SVGA_3D_CMD_DESTROY_GB_MOB;
• cmd->header.size = sizeof(cmd->body);
• cmd->body.mobid = mob->id;
• vmw_fifo_commit(dev_priv, sizeof(*cmd)); if (bo) { vmw_fence_single_bo(bo, NULL); ttm_bo_unreserve(bo);

Thanks. I'll queue this for the next vmwgfx-fixes PULL.

/Thomas