From: <wen.yang99@zte•com.cn>
To: <viresh.kumar@linaro•org>
Cc: wang.yi59@zte•com.cn, linux-pm@vger•kernel.org,
rjw@rjwysocki•net, linux-kernel@vger•kernel.org,
xue.zhihong@zte•com.cn, cheng.shengyu@zte•com.cn,
linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH v6] cpufreq/pasemi: fix an use-after-free inpas_cpufreq_cpu_init()
Date: Tue, 16 Jul 2019 16:26:46 +0800 (CST) [thread overview]
Message-ID: <201907161626465333445@zte.com.cn> (raw)
In-Reply-To: <20190712034409.zyl6sskrr6ra5nd3@vireshk-i7>
[-- Attachment #1.1: Type: text/plain, Size: 3497 bytes --]
> > 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.yang99@zte•com.cn>
> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki•net>
> > Cc: Viresh Kumar <viresh.kumar@linaro•org>
> > Cc: Michael Ellerman <mpe@ellerman•id.au>
> > Cc: linuxppc-dev@lists•ozlabs.org
> > Cc: linux-pm@vger•kernel.org
> > Cc: linux-kernel@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.kumar@linaro.org/
>
> So all you need to do is to remove the label out_unmap_sdcpwr instead.
Okay thank you.
Now this patch
(https://lore.kernel.org/lkml/ee8cf5fb4b4a01fdf9199037ff6d835b935cfd13.1562902877.git.viresh.kumar@linaro.org/)
seems to have not been merged into the linux-next.
In order to avoid code conflicts, we will wait until this patch is merged in and then send v7.
--
Thanks and regards,
Wen
> > + if (err)
> > + goto out_unmap_sdcpwr;
> > +
> > + return 0;
> >
> > out_unmap_sdcpwr:
> > iounmap(sdcpwr_mapbase);
> > --
> > 2.9.5
next prev parent reply other threads:[~2019-07-16 8:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 2:44 [PATCH v6] cpufreq/pasemi: fix an use-after-free in pas_cpufreq_cpu_init() Wen Yang
2019-07-12 3:44 ` Viresh Kumar
2019-07-12 4:32 ` [PATCH v6] cpufreq/pasemi: fix an use-after-free inpas_cpufreq_cpu_init() wen.yang99
2019-07-16 8:26 ` wen.yang99 [this message]
2019-07-16 9:00 ` Viresh Kumar
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