linux-kernel - Re: [PATCH v2] checkpatch: Add a warning for log messages that don't end in a new line

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Message-ID: <alpine.DEB.2.20.1711270704420.2369@hadrien>
Date:   Mon, 27 Nov 2017 07:08:28 +0100 (CET)
From:   Julia Lawall <julia.lawall@...6.fr>
To:     Joe Perches <joe@...ches.com>
cc:     Logan Gunthorpe <logang@...tatee.com>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Andy Whitcroft <apw@...onical.com>
Subject: Re: [PATCH v2] checkpatch: Add a warning for log messages that don't
 end in a new line



On Sun, 26 Nov 2017, Joe Perches wrote:

> On Sun, 2017-11-26 at 23:44 +0100, Julia Lawall wrote:
> > My semantic patch and results are below.  The semantic patch has some
> > features that may or may not be desired:
> >
> > 1.  It goes beyond printk, pr_xxx, dev_xxx, and netdev_xxx, by finding
> > functions that are sometimes used with a format string ending with a
> > newline.  To reduce false positives, such a function is ignored if it is
> > sometimes used with a string that ends in a space.  This could lead to
> > false positives where actually one of the calls has a \n that it should
> > not have.
> >
> > 2.  Coccinelle puts multipart strings on a single line.  So the rule goes
> > a little further and eliminates the multipartness.  Basically "xxx " "yyy"
> > becomes "xxx yyy" regardless of the length of the result.
>
> What about the semi-common string concatenation "foo" #var "bar" ?

I don't think this is an issue.  There is no " " pattern in this.  It's
true that if the pieces were on separate lines, Coccinelle will now put
them on a single line.  I'm not sure I want to bother with this.

> > 3.  Some prints appear not to end with a newline because they end with \n.
> > where .\n was likely intended.  Instead of creating \n.\n, the semantic
> > patch just moves the .to the left of the . And if there was .\n. it just
> > drops the final period.
>
> That may be a problem if the sentence is "something...\n"

I think I was not clear.  The sentence ends in ".\n.".

> There seem to be many false positives in here too.

Could you point to something specifically?  I saw a lot of cases with
prints followed by returns and gotos.  I guess those are not likely false
positives.

julia