--- a/dom/canvas/WebGL2ContextMRTs.cpp
+++ b/dom/canvas/WebGL2ContextMRTs.cpp
@@ -89,79 +89,107 @@ WebGL2Context::ClearBufferfv_base(GLenum
     }
 
     gl->fClearBufferfv(buffer, drawbuffer, value);
 }
 
 void
 WebGL2Context::ClearBufferiv(GLenum buffer, GLint drawbuffer, const dom::Int32Array& value)
 {
+    if (IsContextLost()) {
+        return;
+    }
+
     value.ComputeLengthAndData();
     if (!ValidateClearBuffer("clearBufferiv", buffer, drawbuffer, value.Length())) {
         return;
     }
 
     ClearBufferiv_base(buffer, drawbuffer, value.Data());
 }
 
 void
 WebGL2Context::ClearBufferiv(GLenum buffer, GLint drawbuffer, const dom::Sequence<GLint>& value)
 {
+    if (IsContextLost()) {
+        return;
+    }
+
     if (!ValidateClearBuffer("clearBufferiv", buffer, drawbuffer, value.Length())) {
         return;
     }
 
     ClearBufferiv_base(buffer, drawbuffer, value.Elements());
 }
 
 void
 WebGL2Context::ClearBufferuiv(GLenum buffer, GLint drawbuffer, const dom::Uint32Array& value)
 {
+    if (IsContextLost()) {
+        return;
+    }
+
     value.ComputeLengthAndData();
     if (!ValidateClearBuffer("clearBufferuiv", buffer, drawbuffer, value.Length())) {
         return;
     }
 
     ClearBufferuiv_base(buffer, drawbuffer, value.Data());
 }
 
 void
 WebGL2Context::ClearBufferuiv(GLenum buffer, GLint drawbuffer, const dom::Sequence<GLuint>& value)
 {
+    if (IsContextLost()) {
+        return;
+    }
+
     if (!ValidateClearBuffer("clearBufferuiv", buffer, drawbuffer, value.Length())) {
         return;
     }
 
     ClearBufferuiv_base(buffer, drawbuffer, value.Elements());
 }
 
 void
 WebGL2Context::ClearBufferfv(GLenum buffer, GLint drawbuffer, const dom::Float32Array& value)
 {
+    if (IsContextLost()) {
+        return;
+    }
+
     value.ComputeLengthAndData();
     if (!ValidateClearBuffer("clearBufferfv", buffer, drawbuffer, value.Length())) {
         return;
     }
 
     ClearBufferfv_base(buffer, drawbuffer, value.Data());
 }
 
 void
 WebGL2Context::ClearBufferfv(GLenum buffer, GLint drawbuffer, const dom::Sequence<GLfloat>& value)
 {
+    if (IsContextLost()) {
+        return;
+    }
+
     if (!ValidateClearBuffer("clearBufferfv", buffer, drawbuffer, value.Length())) {
         return;
     }
 
     ClearBufferfv_base(buffer, drawbuffer, value.Elements());
 }
 
 void
 WebGL2Context::ClearBufferfi(GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil)
 {
+    if (IsContextLost()) {
+        return;
+    }
+
     if (buffer != LOCAL_GL_DEPTH_STENCIL) {
         return ErrorInvalidEnumInfo("clearBufferfi: buffer", buffer);
     }
     MakeContextCurrent();
     gl->fClearBufferfi(buffer, drawbuffer, depth, stencil);
 }
 
 } // namespace mozilla