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From:   Navid Emamdoost <navid.emamdoost@gmail.com>
Date:   Tue, 22 Oct 2019 23:50:55 -0500
Message-ID: <CAEkB2ES=S64T9FH8bSj=muXD3hSXc3-MWEVt_0sggoTdZFQswg@mail.gmail.com>
Subject: Re: [PATCH] clocksource/drivers: Fix memory leak in ttc_setup_clockevent
To:     Michal Simek <michal.simek@xilinx.com>
Cc:     Markus Elfring <Markus.Elfring@web.de>,
        linux-arm-kernel@lists.infradead.org,
        LKML <linux-kernel@vger.kernel.org>,
        kernel-janitors@vger.kernel.org,
        Navid Emamdoost <emamd001@umn.edu>, Kangjie Lu <kjlu@umn.edu>,
        Stephen McCamant <smccaman@umn.edu>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>
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Thanks for the feedback, I updated this patch and sent v2.
Also, I submitted a patch to fix the error handling path in
ttc_setup_clocksource(). Here is the link to it:
https://lore.kernel.org/patchwork/patch/1143242/

On Tue, Oct 22, 2019 at 3:51 AM Michal Simek <michal.simek@xilinx.com> wrot=
e:
>
> On 22. 10. 19 10:26, Markus Elfring wrote:
> >> In the impelementation of ttc_setup_clockevent() the allocated memory
> >> for ttcce should be released if clk_notifier_register() fails.
> >
> > * Please avoid the copying of typos from previous change descriptions.
> >
> > * Under which circumstances will an =E2=80=9Cimperative mood=E2=80=9D m=
atter for you here?
> >   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tr=
ee/Documentation/process/submitting-patches.rst?id=3D7d194c2100ad2a6dded545=
887d02754948ca5241#n151
> >
> >
> >> +++ b/drivers/clocksource/timer-cadence-ttc.c
> >> @@ -424,6 +424,7 @@ static int __init ttc_setup_clockevent(struct clk =
*clk,
> >>                                  &ttcce->ttc.clk_rate_change_nb);
> >>      if (err) {
> >>              pr_warn("Unable to register clock notifier.\n");
> >> +            kfree(ttcce);
> >>              return err;
> >>      }
> >
> > This addition looks correct.
> > But I would prefer to move such exception handling code to the end of
> > this function implementation so that duplicate source code will be redu=
ced.
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree=
/Documentation/process/coding-style.rst?id=3D7d194c2100ad2a6dded545887d0275=
4948ca5241#n450
>
> Just a note. Maybe you should also consider to fix this error path in
> ttc_setup_clocksource() when notifier also can fail that there is no
> need to continue with code execution.
>
> Thanks,
> Michal


--=20
Navid.