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From: Maria Neptune <maria.elysse.n@gmail.com>
To: Martin Galvan <omgalvan.86@gmail.com>
Cc: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>,
	kernelnewbies@kernelnewbies.org
Subject: Re: Try/catch for modules?
Date: Fri, 18 Oct 2019 11:48:48 -0400	[thread overview]
Message-ID: <CAG=DERm2JFuDXOLSCzHOruem38xCK=ziaxojYZfw==CGx=7ZyA@mail.gmail.com> (raw)
In-Reply-To: <CAN19L9EF01s_yGwzNLtLp+3HYUxrHrt65XPEd0utvonLZAY8=g@mail.gmail.com>


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Edsger Dijkstra will haunt is forever, it seems.  Gotos are just a tool,
and this is one of the few places they're the best tool for the job. And
generally in-kernel the acceptable method is to not forget a null check, as
Valdis mentioned. It's cool to forget a null check on your own machine (who
among us hasn't?) but if you're contributing/shipping code you gotta know
that those pointers are good.

On Fri, Oct 18, 2019, 11:44 Martin Galvan <omgalvan.86@gmail.com> wrote:

> El jue., 17 oct. 2019 a las 19:13, Valdis Klētnieks
> (<valdis.kletnieks@vt.edu>) escribió:
> >
> > For starters, the *correct* in-kernel way to deal with this is:
> >         if (!ptr) {
> >                 printk("You blew it!\n");
> >                 goto you_blew_it;
> >         }
>
> goto statements are harmful. In any case, what I meant was to have
> some sort of safety net to prevent exceptions (i.e. if I screw up and
> forget a NULL check) from panicking the system.
>
> > Also, "current PID" and "my module" aren't two things that can
> correspond....
>
> I don't understand what you mean by that. Module code (e.g. an ioctl)
> runs as some process. In the case of an ioctl, I'd assume it's the
> same PID of the user process.
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>

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  parent reply	other threads:[~2019-10-18 15:50 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-17 13:37 Try/catch for modules? Martin Galvan
     [not found] ` <CAG=DERmX7AU8YkEAYnPLfPKCLD=1OugmD95R9wZ3CepXvqzd2Q@mail.gmail.com>
2019-10-17 13:42   ` Maria Neptune
2019-10-17 13:51     ` Ruben Safir
2019-10-17 22:12 ` Valdis Klētnieks
2019-10-18 15:43   ` Martin Galvan
2019-10-18 15:47     ` Anuz Pratap Singh Tomar
2019-10-18 15:48     ` Maria Neptune [this message]
2019-10-18 16:04     ` Bernd Petrovitsch
2019-10-18 16:11       ` Martin Galvan
2019-10-18 16:18         ` Bernd Petrovitsch
2019-10-18 17:02         ` Ruben Safir
2019-10-18 17:05           ` Martin Galvan
2019-10-18 18:52             ` Ruben Safir
2019-10-18 18:53             ` Ruben Safir
2019-10-18 19:08               ` Ruben Safir
2019-10-18 21:53         ` Valdis Klētnieks
2019-10-18 22:09           ` Martin Galvan
2019-10-18 22:28             ` Greg KH
2019-10-18 18:48     ` Ruben Safir
2019-10-18 21:24     ` Rik van Riel
2019-10-18 21:32       ` Ruben Safir
2019-10-18 21:37       ` Ruben Safir
2019-10-18 22:59     ` Valdis Klētnieks
2019-10-19  7:46 ` Bjørn Mork

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