> > The cpu variable is still being used in the of_get_property() call
> > after the of_node_put() call, which may result in use-after-free.
> >
> > Fixes: a9acc26b75f6 ("cpufreq/pasemi: fix possible object reference leak")
> > Signed-off-by: Wen Yang <wen.yan...@zte.com.cn>
> > Cc: "Rafael J. Wysocki" <r...@rjwysocki.net>
> > Cc: Viresh Kumar <viresh.ku...@linaro.org>
> > Cc: Michael Ellerman <m...@ellerman.id.au>
> > Cc: linuxppc-dev@lists.ozlabs.org
> > Cc: linux...@vger.kernel.org
> > Cc: linux-ker...@vger.kernel.org
> > ---
> > v6: keep the blank line and fix warning: label 'out_unmap_sdcpwr' defined
> > but not used.
> > v5: put together the code to get, use, and release cpu device_node.
> > v4: restore the blank line.
> > v3: fix a leaked reference.
> > v2: clean up the code according to the advice of viresh.
> >
> > drivers/cpufreq/pasemi-cpufreq.c | 26 ++++++++++++++------------
> > 1 file changed, 14 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/cpufreq/pasemi-cpufreq.c
> > b/drivers/cpufreq/pasemi-cpufreq.c
> > index 6b1e4ab..7d557f9 100644
> > --- a/drivers/cpufreq/pasemi-cpufreq.c
> > +++ b/drivers/cpufreq/pasemi-cpufreq.c
> > @@ -131,10 +131,18 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy
> > *policy)
> > int err = -ENODEV;
> >
> > cpu = of_get_cpu_node(policy->cpu, NULL);
> > + if (!cpu)
> > + goto out;
> >
> > + max_freqp = of_get_property(cpu, "clock-frequency", NULL);
> > of_node_put(cpu);
> > - if (!cpu)
> > + if (!max_freqp) {
> > + err = -EINVAL;
> > goto out;
> > + }
> > +
> > + /* we need the freq in kHz */
> > + max_freq = *max_freqp / 1000;
> >
> > dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
> > if (!dn)
> > @@ -171,16 +179,6 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy
> > *policy)
> > }
> >
> > pr_debug("init cpufreq on CPU %d\n", policy->cpu);
> > -
> > - max_freqp = of_get_property(cpu, "clock-frequency", NULL);
> > - if (!max_freqp) {
> > - err = -EINVAL;
> > - goto out_unmap_sdcpwr;
> > - }
> > -
> > - /* we need the freq in kHz */
> > - max_freq = *max_freqp / 1000;
> > -
> > pr_debug("max clock-frequency is at %u kHz\n", max_freq);
> > pr_debug("initializing frequency table\n");
> >
> > @@ -196,7 +194,11 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy
> > *policy)
> > policy->cur = pas_freqs[cur_astate].frequency;
> > ppc_proc_freq = policy->cur * 1000ul;
> >
> > - return cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
> > + err = cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
>
> So you are trying to fix an earlier issue here with this. Should have
> been a separate patch. Over that I have just sent a patch now to make
> this routine return void.
>
> https://lore.kernel.org/lkml/ee8cf5fb4b4a01fdf9199037ff6d835b935cfd13.1562902877.git.viresh.ku...@linaro.org/
>
> So all you need to do is to remove the label out_unmap_sdcpwr instead.
Ok, thanks.
--
Cheers,
Wen
