From 6950e23e54b1c94abf8c60c1ddfac79133d41de2 Mon Sep 17 00:00:00 2001 From: Alexey Khoroshilov Date: Sat, 1 Mar 2014 01:20:18 +0400 Subject: [PATCH] drm/vmwgfx: avoid null pointer dereference at failure paths 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 Reviewed-by: Thomas Hellstrom --- 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); -- 2.20.1