checkpatch: add --strict test for switch/default missing break

switch default case is sometimes written as "default:;".  This can cause
new cases added below the default to be defective.

Suggest adding a break; after empty default cases to avoid fallthrough
defects.

Fixed indentation in the other semicolon test above it.

Suggested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 2 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index f27b0b53e3e..725c59611e9 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3448,8 +3448,22 @@ sub process {
 
 # check for multiple semicolons
                 if ($line =~ /;\s*;\s*$/) {
-                    WARN("ONE_SEMICOLON",
-                         "Statements terminations use 1 semicolon\n" . $herecurr);
+                        WARN("ONE_SEMICOLON",
+                             "Statements terminations use 1 semicolon\n" . $herecurr);
+                }
+
+# check for switch/default statements without a break;
+                if ($^V && $^V ge 5.10.0 &&
+                    defined $stat &&
+                    $stat =~ /^\+[$;\s]*(?:case[$;\s]+\w+[$;\s]*:[$;\s]*|)*[$;\s]*\bdefault[$;\s]*:[$;\s]*;/g) {
+                        my $ctx = '';
+                        my $herectx = $here . "\n";
+                        my $cnt = statement_rawlines($stat);
+                        for (my $n = 0; $n < $cnt; $n++) {
+                                $herectx .= raw_line($linenr, $n) . "\n";
+                        }
+                        WARN("DEFAULT_NO_BREAK",
+                             "switch default: should use break\n" . $herectx);
                 }
 
 # check for gcc specific __FUNCTION__