Re: [PATCH v4 RESEND] checkpatch: check for missing Fixes tags

From: Joe Perches
Date: Mon Jun 10 2024 - 11:10:30 EST


On Mon, 2024-06-10 at 14:13 +0300, Dan Carpenter wrote:
> This check looks for common words that probably indicate a patch
> is a fix. For now the regex is:
>
> (?:(?:BUG: K.|UB)SAN: |Call Trace:|stable\@|syzkaller)/)
>
> Why are stable patches encouraged to have a fixes tag? Some people mark
> their stable patches as "# 5.10" etc. This is useful but a Fixes tag is
> still a good idea. For example, the Fixes tag helps in review. It
> helps people to not cherry-pick buggy patches without also
> cherry-picking the fix.
>
> Also if a bug affects the 5.7 kernel some people will round it up to
> 5.10+ because 5.7 is not supported on kernel.org. It's possible the Bad
> Binder bug was caused by this sort of gap where companies outside of
> kernel.org are supporting different kernels from kernel.org.
>
> Should it be counted as a Fix when a patch just silences harmless
> WARN_ON() stack trace. Yes. Definitely.
>
> Is silencing compiler warnings a fix? It seems unfair to the original
> authors, but we use -Werror now, and warnings break the build so let's
> just add Fixes tags. I tell people that silencing static checker
> warnings is not a fix but the rules on this vary by subsystem.
>
> Is fixing a minor LTP issue (Linux Test Project) a fix? Probably? It's
> hard to know what to do if the LTP test has technically always been
> broken.
>
> One clear false positive from this check is when someone updated their
> debug output and included before and after Call Traces. Or when crashes
> are introduced deliberately for testing. In those cases, you should
> just ignore checkpatch.
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> +# These indicate a bug fix
> + if (!$in_header_lines && !$is_patch &&
> + $line =~ /^This reverts commit/) {
> + $is_revert = 1;
> + }
> +
> + if (!$in_header_lines && !$is_patch &&
> + $line =~ /(?:(?:BUG: K.|UB)SAN: |Call Trace:|stable\@|syzkaller)/) {
> + $needs_fixes_tag = 1;

Maybe use
$line =~ /((?:(?:BUG: K.|UB)SAN: |Call Trace:|stable\@|syzkaller))/) {
$needs_fixes_tag = $1;

> @@ -7697,6 +7715,12 @@ sub process {
> ERROR("NOT_UNIFIED_DIFF",
> "Does not appear to be a unified-diff format patch\n");
> }
> + if ($is_patch && $has_commit_log && $chk_fixes_tag) {
> + if ($needs_fixes_tag && !$is_revert && !$fixes_tag) {

and

+ if ($needs_fixes_tag ne "" && !$is_revert && !$fixes_tag) {

> + WARN("MISSING_FIXES_TAG",
> + "This looks like a fix but there is no Fixes: tag\n");

and

"The commit message has '$needs_fixes_tag', perhaps it also needs a 'Fixes:' tag?\n");