grep: avoid false-positive UMR

For some inputs, valgrind would report an uninitialized
memory read error, but it was harmless.
* src/grep.c (fillbuf): Initialize those trailing bytes.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/grep.c b/src/grep.c
index 2276e93a..c85fc6e4 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -810,6 +810,12 @@ fillbuf (size_t save, struct stat const *st)
 
   fillsize = undossify_input (readbuf, fillsize);
   buflim = readbuf + fillsize;
+
+  /* Initialize the following word, because skip_easy_bytes and some
+     matchers read (but do not use) those bytes.  This avoids false
+     positive reports of these bytes being used uninitialized.  */
+  memset (buflim, 0, sizeof (uword));
+
   return cc;
 }