Merge branch 'nm/grep-object-sha1-lock'

* nm/grep-object-sha1-lock:
  grep: Fix race condition in delta_base_cache

Conflicts:
	builtin/grep.c

builtin/grep.c

@@ -598,8 +598,11 @@ static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
 		struct strbuf base;
 		int hit, len;
 
+		read_sha1_lock();
 		data = read_object_with_reference(obj->sha1, tree_type,
 						  &size, NULL);
+		read_sha1_unlock();
+
 		if (!data)
 			die(_("unable to read tree (%s)"), sha1_to_hex(obj->sha1));