Re: [PATCH] checkpatch: check for missing \n at the end of logging message

[Marion & Christophe JAILLET]

Le 08/04/2020 Ã 02:33, Joe Perches a ÃcritÂ:
> On Tue, 2020-04-07 at 22:49 +0200, Christophe JAILLET wrote:
> > Strings logged with pr_xxx and dev_xxx often lack a trailing '\n'.
> > Introduce new tests to try to catch them early.
> >
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> > This is more a PoC for now.
> >
> > Regex could be improved, merged, ...
> > We could also check for surrounding pr_cont...
> >
> > This patch is based on idea from [1]. coccinelle spots too many places
> > where \n are missing (~ 2800 with the heuristic I've used).
> > Fixing them would be painful.
> > I instead propose to teach checkpatch.pl about it to try to spot cases
> > early and avoid introducing new cases.
> >
> > [1]: https://marc.info/?l=kernel-janitors&m=158619533629657&w=4
> > ---
> >   scripts/checkpatch.pl | 10 ++++++++++
> >   1 file changed, 10 insertions(+)
> >
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index c392ab8ea12e..792804bd6ad9 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -5676,6 +5676,16 @@ sub process {
> >   			}
> >   		}
> >   
> > +# check for missing \n at the end of logging function
> > +		if ($line =~ /\bpr_(emerg|alert|crit|err|warning|warn|notice|info|debug|dbg)\s*\("([^"]*(?<!\\n))"/) {
> > +			WARN("MISSING NL",
> > +			     "Possible missing '\\n' at the end of a log message\n" . $hereprev);
> > +		}
> > +		if ($line =~ /\bdev_(emerg|alert|crit|err|warning|warn|notice|info|debug|dbg)\s*\([^,]*,\s*"([^"]*(?<!\\n))"/) {
> > +			WARN("MISSING NL",
> > +			     "Possible missing '\\n' at the end of a log message\n" . $hereprev);
> > +		}
> This can't work as string is masked to "XXX"

Ok. I wasn't aware of that.

I tested the regex with regex101.org and only tested with patches that 
trigger the checkpatch.pl test, and it worked fine for me.
I didn't test with string with trailing \n, that should NOT trigger the 
test. I should have! :(

> This is probably better using $stat and checking if a "XX" format
> string exists as 1st or 2nd arg and adding an extraction
> from the $rawline equivalent and checking that.
>
> Also this test should probably using $logFunctions and check
> if the initial block is one of the known functions that
> use a newline termination (pr_|dev_|netdev_|wiphy_)

Agreed but your perl and regex is much more fluent than mine. ;-)

CJ