handle bad xform in drawTextRSXform

Bug: oss-fuzz:6955
Change-Id: Ide1f57459a611980a86afea577eb4c2425e49e63
Reviewed-on: https://skia-review.googlesource.com/114782
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/src/core/SkDevice.cpp b/src/core/SkDevice.cpp
index 210af808c9..96a7e8dbfe 100644
--- a/src/core/SkDevice.cpp
+++ b/src/core/SkDevice.cpp
@@ -511,8 +511,11 @@ void SkBaseDevice::drawTextRSXform(const void* text, size_t len,
         // with a localmatrixshader so that the shader draws as if there was no change to the ctm.
         if (shader) {
             SkMatrix inverse;
-            SkAssertResult(localM.invert(&inverse));
-            localPaint.setShader(shader->makeWithLocalMatrix(inverse));
+            if (localM.invert(&inverse)) {
+                localPaint.setShader(shader->makeWithLocalMatrix(inverse));
+            } else {
+                localPaint.setShader(nullptr);  // can't handle this xform
+            }
         }
 
         int subLen = proc((const char*)text);