From: Jianglei Nie <niejianglei2021@163.com>
To: daniel.lezcano@kernel.org, rafael@kernel.org
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
Jianglei Nie <niejianglei@gmail.com>
Subject: [PATCH] powercap: DTPM: Fix reference leak in cpuhp_dtpm_cpu_offline()
Date: Thu, 25 Nov 2021 00:46:57 +0800 [thread overview]
Message-ID: <20211124164657.20519-1-niejianglei2021@163.com> (raw)
From: Jianglei Nie <niejianglei@gmail.com>
In line 153 (#1), cpufreq_cpu_get() increments the kobject reference
counter of the policy it returned on success. According to the
document, the policy returned by cpufreq_cpu_get() has to be
released with the help of cpufreq_cpu_put() to balance its kobject
reference counter properly. Forgetting the cpufreq_cpu_put()
operation will result in reference leak.
We can fix it by calling cpufreq_cpu_put() before the function
returns (#2, #3 and #4).
147 static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
148 {
153 policy = cpufreq_cpu_get(cpu);
// #1: reference increment
155 if (!policy)
156 return 0;
158 pd = em_cpu_get(cpu);
159 if (!pd)
160 return -EINVAL; // #2: missing reference decrement
166 if (cpumask_weight(policy->cpus) != 1)
167 return 0; // #3: missing reference decrement
174 return 0; // #4: missing reference decrement
175 }
Signed-off-by: Jianglei Nie <niejianglei@gmail.com>
---
drivers/powercap/dtpm_cpu.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
index 51c366938acd..182a07ee14b6 100644
--- a/drivers/powercap/dtpm_cpu.c
+++ b/drivers/powercap/dtpm_cpu.c
@@ -156,21 +156,26 @@ static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
return 0;
pd = em_cpu_get(cpu);
- if (!pd)
+ if (!pd) {
+ cpufreq_cpu_put(policy);
return -EINVAL;
+ }
dtpm = per_cpu(dtpm_per_cpu, cpu);
power_sub(dtpm, pd);
- if (cpumask_weight(policy->cpus) != 1)
+ if (cpumask_weight(policy->cpus) != 1) {
+ cpufreq_cpu_put(policy);
return 0;
+ }
for_each_cpu(cpu, policy->related_cpus)
per_cpu(dtpm_per_cpu, cpu) = NULL;
dtpm_unregister(dtpm);
+ cpufreq_cpu_put(policy);
return 0;
}
--
2.25.1
next reply other threads:[~2021-11-24 17:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 16:46 Jianglei Nie [this message]
2021-12-10 7:28 [PATCH] powercap: DTPM: Fix reference leak in cpuhp_dtpm_cpu_offline() Jianglei Nie
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211124164657.20519-1-niejianglei2021@163.com \
--to=niejianglei2021@163.com \
--cc=daniel.lezcano@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=niejianglei@gmail.com \
--cc=rafael@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).