From: Dan Carpenter <dan.carpenter@oracle.com>
To: kbuild@lists.01.org, Chanwoo Choi <cw00.choi@samsung.com>
Cc: lkp@intel.com, kbuild-all@lists.01.org, linux-kernel@vger.kernel.org
Subject: [chanwoo:devfreq-testing 5/5] drivers/devfreq/governor_passive.c:190 cpufreq_passive_notifier_call() warn: variable dereferenced before check 'freqs' (see line 188)
Date: Fri, 6 May 2022 09:52:22 +0300 [thread overview]
Message-ID: <202205060340.kwfOSVud-lkp@intel.com> (raw)
tree: https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git devfreq-testing
head: f8605f8ed725beedd71e89872e49178b930250d4
commit: f8605f8ed725beedd71e89872e49178b930250d4 [5/5] PM / devfreq: Use cpufreq_policy instead of NR_CPU
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20220506/202205060340.kwfOSVud-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
New smatch warnings:
drivers/devfreq/governor_passive.c:190 cpufreq_passive_notifier_call() warn: variable dereferenced before check 'freqs' (see line 188)
Old smatch warnings:
drivers/devfreq/governor_passive.c:315 cpufreq_passive_register_notifier() warn: possible memory leak of 'parent_cpu_data'
drivers/devfreq/governor_passive.c:379 devfreq_passive_event_handler() warn: variable dereferenced before check 'p_data' (see line 376)
vim +/freqs +190 drivers/devfreq/governor_passive.c
009cb1af01de85 Saravana Kannan 2021-03-02 177 static int cpufreq_passive_notifier_call(struct notifier_block *nb,
009cb1af01de85 Saravana Kannan 2021-03-02 178 unsigned long event, void *ptr)
009cb1af01de85 Saravana Kannan 2021-03-02 179 {
f8605f8ed725be Chanwoo Choi 2022-04-27 180 struct devfreq_passive_data *p_data =
009cb1af01de85 Saravana Kannan 2021-03-02 181 container_of(nb, struct devfreq_passive_data, nb);
f8605f8ed725be Chanwoo Choi 2022-04-27 182 struct devfreq *devfreq = (struct devfreq *)p_data->this;
009cb1af01de85 Saravana Kannan 2021-03-02 183 struct devfreq_cpu_data *parent_cpu_data;
009cb1af01de85 Saravana Kannan 2021-03-02 184 struct cpufreq_freqs *freqs = ptr;
009cb1af01de85 Saravana Kannan 2021-03-02 185 unsigned int cur_freq;
009cb1af01de85 Saravana Kannan 2021-03-02 186 int ret;
009cb1af01de85 Saravana Kannan 2021-03-02 187
f8605f8ed725be Chanwoo Choi 2022-04-27 @188 parent_cpu_data = get_parent_cpu_data(p_data, freqs->policy->cpu);
^^^^^^^^
Dereference
f8605f8ed725be Chanwoo Choi 2022-04-27 189
f8605f8ed725be Chanwoo Choi 2022-04-27 @190 if (event != CPUFREQ_POSTCHANGE || !freqs || !parent_cpu_data)
^^^^^^
Check too late
009cb1af01de85 Saravana Kannan 2021-03-02 191 return 0;
009cb1af01de85 Saravana Kannan 2021-03-02 192
009cb1af01de85 Saravana Kannan 2021-03-02 193 if (parent_cpu_data->cur_freq == freqs->new)
009cb1af01de85 Saravana Kannan 2021-03-02 194 return 0;
009cb1af01de85 Saravana Kannan 2021-03-02 195
009cb1af01de85 Saravana Kannan 2021-03-02 196 cur_freq = parent_cpu_data->cur_freq;
009cb1af01de85 Saravana Kannan 2021-03-02 197 parent_cpu_data->cur_freq = freqs->new;
009cb1af01de85 Saravana Kannan 2021-03-02 198
009cb1af01de85 Saravana Kannan 2021-03-02 199 mutex_lock(&devfreq->lock);
009cb1af01de85 Saravana Kannan 2021-03-02 200 ret = devfreq_update_target(devfreq, freqs->new);
009cb1af01de85 Saravana Kannan 2021-03-02 201 mutex_unlock(&devfreq->lock);
009cb1af01de85 Saravana Kannan 2021-03-02 202 if (ret) {
009cb1af01de85 Saravana Kannan 2021-03-02 203 parent_cpu_data->cur_freq = cur_freq;
009cb1af01de85 Saravana Kannan 2021-03-02 204 dev_err(&devfreq->dev, "failed to update the frequency.\n");
009cb1af01de85 Saravana Kannan 2021-03-02 205 return ret;
009cb1af01de85 Saravana Kannan 2021-03-02 206 }
009cb1af01de85 Saravana Kannan 2021-03-02 207
009cb1af01de85 Saravana Kannan 2021-03-02 208 return 0;
009cb1af01de85 Saravana Kannan 2021-03-02 209 }
--
0-DAY CI Kernel Test Service
https://01.org/lkp
reply other threads:[~2022-05-06 6:52 UTC|newest]
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