| Message ID | YtZ9qrKeBqmmK8Hv@kili (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/vmwgfx: clean up some error pointer checking | expand |
On Tue, 2022-07-19 at 12:47 +0300, Dan Carpenter wrote: > The vmw_user_bo_noref_lookup() function cannot return NULL. If it > could, then this function would return PTR_ERR(NULL) which is success. > Returning success without initializing "*vmw_bo_p = vmw_bo;" would > lead to an uninitialized variable bug in the caller. Smatch complains > about this: > > drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:1177 vmw_translate_mob_ptr() warn: passing zero to 'PTR_ERR' > drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:1314 vmw_cmd_dx_bind_query() error: uninitialized symbol 'vmw_bo'. Thanks, Dan. I'll push it through the drm-misc tree. z
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c index d49de4905efa..f085dbd4736d 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c @@ -1172,7 +1172,7 @@ static int vmw_translate_mob_ptr(struct vmw_private *dev_priv, vmw_validation_preload_bo(sw_context->ctx); vmw_bo = vmw_user_bo_noref_lookup(sw_context->filp, handle); - if (IS_ERR_OR_NULL(vmw_bo)) { + if (IS_ERR(vmw_bo)) { VMW_DEBUG_USER("Could not find or use MOB buffer.\n"); return PTR_ERR(vmw_bo); } @@ -1226,7 +1226,7 @@ static int vmw_translate_guest_ptr(struct vmw_private *dev_priv, vmw_validation_preload_bo(sw_context->ctx); vmw_bo = vmw_user_bo_noref_lookup(sw_context->filp, handle); - if (IS_ERR_OR_NULL(vmw_bo)) { + if (IS_ERR(vmw_bo)) { VMW_DEBUG_USER("Could not find or use GMR region.\n"); return PTR_ERR(vmw_bo); }
The vmw_user_bo_noref_lookup() function cannot return NULL. If it could, then this function would return PTR_ERR(NULL) which is success. Returning success without initializing "*vmw_bo_p = vmw_bo;" would lead to an uninitialized variable bug in the caller. Smatch complains about this: drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:1177 vmw_translate_mob_ptr() warn: passing zero to 'PTR_ERR' drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:1314 vmw_cmd_dx_bind_query() error: uninitialized symbol 'vmw_bo'. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)