linux-kernel - Re: [PATCH v3 2/3] reboot: fix overflow parsing reboot cpu number

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Message-ID: <20201106101827.GK1602@alley>
Date:   Fri, 6 Nov 2020 11:18:27 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Matteo Croce <mcroce@...ux.microsoft.com>
Cc:     linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
        Arnd Bergmann <arnd@...db.de>, Mike Rapoport <rppt@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Pavel Tatashin <pasha.tatashin@...een.com>,
        Robin Holt <robinmholt@...il.com>,
        Fabian Frederick <fabf@...net.be>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH v3 2/3] reboot: fix overflow parsing reboot cpu number

On Thu 2020-11-05 19:14:27, Matteo Croce wrote:
> On Thu, Nov 5, 2020 at 7:09 PM Petr Mladek <pmladek@...e.com> wrote:
> > > +                     if (reboot_cpu >= num_possible_cpus()) {
> > > +                             pr_err("Ignoring the CPU number in reboot= option. "
> > > +                                    "CPU %d exceeds possible cpu number %d\n",
> >
> > ./scripts/checkpatch.pl used to complain that printk() format parameter should stay
> > on a single line (ignoring 80 char limit). It helps when people are
> > trying to find which code printed a particular message.
> >
> > It is not a big deal here because %d does not allow to search the
> > entire message anyway.
> >
> > I am not sure if Andrew would like to get this fixed. In both cases:
> >
> > Reviewed-by: Petr Mladek <pmladek@...e.com>
> >
> 
> Yes, I saw this warning, but to suppress it I had to write a 133 char
> line, much beyond even the new 100 char limit.
> I expect a smart user to just grep the first half of the string, like
> "Ignoring the CPU number in reboot="

I agree with checkpatch in this case. IMHO, the more reliable way to
grep the string is more important than the 80 or 100 chars per-line.

That said, it is not a big deal in this case because of the %d.
It requires to search only part of the string anyway.

I am perfectly fine with keeping it as is.

Best Regards,
Petr