[PATCH] checkpatch: Add test for printf formats with 0x that emit decimal

[Joe Perches <joe@perches.com>]

0x%<foo> should be used to emit hexadecimal values.

Uses of 0x%[udi] emit decimal values but these should
probably instead use 0x%x variants.

Warn on these uses.

Signed-off-by: Joe Perches <joe@perches.com>
Noticed-by: Hans Wennborg <hans@hanshq.net>
---
 scripts/checkpatch.pl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index da74e65..0178fe0 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4985,6 +4985,10 @@ sub process {
 		while ($line =~ /(?:^|")([X\t]*)(?:"|$)/g) {
 			$string = substr($rawline, $-[1], $+[1] - $-[1]);
 			$string =~ s/%%/__/g;
+			if ($string =~ /(0x(?<!%)%[0-9.\*]*[Ll]*[udi])(?![xX])/) {
+				WARN("PRINTF_HEX_WITH_DECIMAL",
+				     "Using printf format $1 emits a decimal not hexadecimal value\n" . $herecurr);
+			}
 			if ($string =~ /(?<!%)%L[udi]/) {
 				WARN("PRINTF_L",
 				     "\%Ld/%Lu are not-standard C, use %lld/%llu\n" . $herecurr);