+ checkpatch-fix-bad-complex_macro-on-asm-volatile.patch added to mm-nonmm-unstable branch

+ checkpatch-fix-bad-complex_macro-on-asm-volatile.patch added to mm-nonmm-unstable branch

[Andrew Morton]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 3746 bytes --]


The patch titled
     Subject: checkpatch: fix bad COMPLEX_MACRO on asm volatile
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     checkpatch-fix-bad-complex_macro-on-asm-volatile.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/checkpatch-fix-bad-complex_macro-on-asm-volatile.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days

------------------------------------------------------
From: Pierre-Clément Tosi <ptosi@google.com>
Subject: checkpatch: fix bad COMPLEX_MACRO on asm volatile
Date: Sat, 07 Nov 2026 15:57:02 +0100

Commit 42e152931deb ("checkpatch: exclude asm volatile from complex macro
check") added a substitution converting "asm volatile" into "asm_volatile"
so that macros expanding to an asm volatile statement would be treated
like a single function call and excluded from the COMPLEX_MACRO error
("Macros with complex values should be enclosed in parentheses").

However, that substitution was placed after the loop that flattens
parenthesized expressions into "1u" (originally "1").  For a macro without
whitespace between "volatile" and "(", such as:

    #define foo(x) asm volatile("..." : : "r" (x))

flattening the parenthesized argument list first turns the statement into
"asm volatile1u".  Because "1u" starts with a word character, the trailing
word boundary (\b) in /\b_*asm_*\s+_*volatile_*\b/ no longer matches after
"volatile", leaving the space between "asm" and "volatile1u" intact and
causing the macro to still fail the single-lvalue check and trigger a
false-positive COMPLEX_MACRO error.

Move the "asm volatile" to "asm_volatile" substitution before the
parenthesis-flattening loop so that "asm volatile(...)" is first rewritten
to "asm_volatile(...)" and then flattened to "asm_volatile1u" as intended.

Link: https://lore.kernel.org/20261107-checkpatch-asm-complex_macro-v1-1-9a7b3c69fc28@google.com
Fixes: 42e152931deb ("checkpatch: exclude asm volatile from complex macro check")
Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
---

 scripts/checkpatch.pl |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/scripts/checkpatch.pl~checkpatch-fix-bad-complex_macro-on-asm-volatile
+++ a/scripts/checkpatch.pl
@@ -6056,6 +6056,9 @@ sub process {
 			$dstat =~ s/^\s*//s;
 			$dstat =~ s/\s*$//s;
 
+			# Make asm volatile uses seem like a generic function
+			$dstat =~ s/\b_*asm_*\s+_*volatile_*\b/asm_volatile/g;
+
 			# Flatten any parentheses and braces
 			while ($dstat =~ s/\([^\(\)]*\)/1u/ ||
 			       $dstat =~ s/\{[^\{\}]*\}/1u/ ||
@@ -6069,9 +6072,6 @@ sub process {
 			{
 			}
 
-			# Make asm volatile uses seem like a generic function
-			$dstat =~ s/\b_*asm_*\s+_*volatile_*\b/asm_volatile/g;
-
 			my $exceptions = qr{
 				$Declare|
 				# named exceptions
_

Patches currently in -mm which might be from ptosi@google.com are

checkpatch-fix-bad-file_path_changes-on-headers.patch
checkpatch-fix-bad-complex_macro-on-asm-volatile.patch