Catch unicode decode errors search for kernel ver

If a kernel happens to decode to gibberish (including
non-ascii bytes), catch the decoding error when
searching for the kernel version.

Bug: 137041171
Merged-In: Ic035b3a5c8c80025cb3cede7b0fdcf8a2e5a35fd
Change-Id: Ic035b3a5c8c80025cb3cede7b0fdcf8a2e5a35fd

tools/extract_kernel.py

@@ -47,7 +47,10 @@ def get_version(input_bytes, start_idx):
   null_idx = input_bytes.find('\x00', start_idx)
   if null_idx < 0:
     return None
-  linux_banner = input_bytes[start_idx:null_idx].decode()
+  try:
+    linux_banner = input_bytes[start_idx:null_idx].decode()
+  except UnicodeDecodeError:
+    return None
   mo = re.match(LINUX_BANNER_REGEX, linux_banner)
   if mo:
     return mo.group(1)