perf test: Avoid shell test description infinite loop

for_each_shell_test() is already strict in expecting tests to be files
and executable. It is sometimes possible when it iterates over all files
that it finds one that is executable and lacks a newline character. When
this happens the loop never terminates as it doesn't check for EOF.

Add the EOF check to make this loop at least bounded by the file size.

If the description is returned as NULL then also skip the test.

Signed-off-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Riccardo Mancini <[email protected]>
Cc: Sohaib Mohamed <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: captain5050

tools/perf/tests/builtin-test.c

@@ -279,14 +279,17 @@ static const char *shell_test__description(char *description, size_t size,
 {
 	FILE *fp;
 	char filename[PATH_MAX];
+	int ch;
 
 	path__join(filename, sizeof(filename), path, name);
 	fp = fopen(filename, "r");
 	if (!fp)
 		return NULL;
 
 	/* Skip shebang */
-	while (fgetc(fp) != '\n');
+	do {
+		ch = fgetc(fp);
+	} while (ch != EOF && ch != '\n');
 
 	description = fgets(description, size, fp);
 	fclose(fp);
@@ -417,7 +420,8 @@ static int run_shell_tests(int argc, const char *argv[], int i, int width,
 			.priv = &st,
 		};
 
-		if (!perf_test__matches(test_suite.desc, curr, argc, argv))
+		if (test_suite.desc == NULL ||
+		    !perf_test__matches(test_suite.desc, curr, argc, argv))
 			continue;
 
 		st.file = ent->d_name;