From: "Chen, Rong A" <rong.a.chen@intel.com>
To: Viresh Kumar <viresh.kumar@linaro.org>,
kernel test robot <lkp@intel.com>
Cc: Thara Gopinath <thara.gopinath@linaro.org>,
clang-built-linux@googlegroups.com, kbuild-all@lists.01.org,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [linux-next:master 8440/9522] drivers/cpufreq/qcom-cpufreq-hw.c:294:3: warning: Value stored to 'opp' is never read [clang-analyzer-deadcode.DeadStores]
Date: Tue, 24 Aug 2021 14:53:28 +0800 [thread overview]
Message-ID: <38f16bcf-40bc-c400-ef64-da8e43b1135f@intel.com> (raw)
In-Reply-To: <20210823065211.mzagmzexavwxu4vy@vireshk-i7>
On 8/23/2021 2:52 PM, Viresh Kumar wrote:
> On 22-08-21, 19:41, kernel test robot wrote:
>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> head: 86ed57fd8c93fdfaabb4f58e78455180fa7d8a84
>> commit: 86afc1df661a99dcd6b8d264cae171f1ead2b7b8 [8440/9522] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
>> config: arm-randconfig-c002-20210822 (attached as .config)
>> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project a83d99c55ebb14532c414066a5aa3bdb65389965)
>> reproduce (this is a W=1 build):
>> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>> chmod +x ~/bin/make.cross
>> # install arm cross compiling tool for clang build
>> # apt-get install binutils-arm-linux-gnueabi
>> # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=86afc1df661a99dcd6b8d264cae171f1ead2b7b8
>> git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>> git fetch --no-tags linux-next master
>> git checkout 86afc1df661a99dcd6b8d264cae171f1ead2b7b8
>> # save the attached .config to linux build tree
>> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm clang-analyzer
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>
> This doesn't look right, it says issues are with cpufreq-hw driver but
> points at hid-core ?
Hi Viresh,
The warning with the prefix ">>" is pointed to this commit,
others are only for reference.
Best Regards,
Rong Chen
>
>> clang-analyzer warnings: (new ones prefixed by >>)
<snip>
>>>> drivers/cpufreq/qcom-cpufreq-hw.c:294:3: warning: Value stored to 'opp' is never read [clang-analyzer-deadcode.DeadStores]
>> opp = dev_pm_opp_find_freq_ceil(dev, &freq_hz);
>> ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/cpufreq/qcom-cpufreq-hw.c:294:3: note: Value stored to 'opp' is never read
>> opp = dev_pm_opp_find_freq_ceil(dev, &freq_hz);
>> ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> Suppressed 2 warnings (2 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 2 warnings generated.
>> Suppressed 2 warnings (2 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 2 warnings generated.
>> Suppressed 2 warnings (2 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 2 warnings generated.
>> Suppressed 2 warnings (2 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 7 warnings generated.
>> Suppressed 7 warnings (7 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 3 warnings generated.
>> Suppressed 3 warnings (3 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 2 warnings generated.
>> Suppressed 2 warnings (2 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 2 warnings generated.
>> Suppressed 2 warnings (2 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 3 warnings generated.
>> Suppressed 3 warnings (3 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 3 warnings generated.
>> Suppressed 3 warnings (3 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 3 warnings generated.
>> Suppressed 3 warnings (3 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 6 warnings generated.
>> Suppressed 6 warnings (6 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 2 warnings generated.
>> Suppressed 2 warnings (2 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 2 warnings generated.
>> Suppressed 2 warnings (2 in non-user code).
>> Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
>> 7 warnings generated.
>> drivers/dma/xgene-dma.c:445:36: warning: The result of the left shift is undefined due to shifting by '32', which is greater or equal to the width of type 'int' [clang-analyzer-core.UndefinedBinaryOperatorResult]
>> desc1->m2 |= cpu_to_le64((scf[i] << ((i + 1) * 8)));
>> ^
>> include/linux/byteorder/generic.h:86:21: note: expanded from macro 'cpu_to_le64'
>> #define cpu_to_le64 __cpu_to_le64
>> ^
>> drivers/dma/xgene-dma.c:895:15: note: Assuming 'dchan' is non-null
>> if (unlikely(!dchan || !len))
>> ^
>> include/linux/compiler.h:78:42: note: expanded from macro 'unlikely'
>> # define unlikely(x) __builtin_expect(!!(x), 0)
>> ^
>> drivers/dma/xgene-dma.c:895:15: note: Left side of '||' is false
>> if (unlikely(!dchan || !len))
>> ^
>> drivers/dma/xgene-dma.c:895:25: note: Assuming 'len' is not equal to 0
>> if (unlikely(!dchan || !len))
>> ^
>> include/linux/compiler.h:78:42: note: expanded from macro 'unlikely'
>> # define unlikely(x) __builtin_expect(!!(x), 0)
>> ^
>> drivers/dma/xgene-dma.c:895:2: note: Taking false branch
>> if (unlikely(!dchan || !len))
>> ^
>> drivers/dma/xgene-dma.c:898:9: note: Left side of '&&' is false
>> chan = to_dma_chan(dchan);
>> ^
>> drivers/dma/xgene-dma.c:191:2: note: expanded from macro 'to_dma_chan'
>> container_of(dchan, struct xgene_dma_chan, dma_chan)
>> ^
>> include/linux/kernel.h:495:61: note: expanded from macro 'container_of'
>> BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
>> ^
>> drivers/dma/xgene-dma.c:898:9: note: Taking false branch
>> chan = to_dma_chan(dchan);
>> ^
>> drivers/dma/xgene-dma.c:191:2: note: expanded from macro 'to_dma_chan'
>> container_of(dchan, struct xgene_dma_chan, dma_chan)
>> ^
>> include/linux/kernel.h:495:2: note: expanded from macro 'container_of'
>> BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
>> ^
>> include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG'
>> #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>> ^
>> include/linux/compiler_types.h:328:2: note: expanded from macro 'compiletime_assert'
>> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>> ^
>> include/linux/compiler_types.h:316:2: note: expanded from macro '_compiletime_assert'
>> __compiletime_assert(condition, msg, prefix, suffix)
>> ^
>> include/linux/compiler_types.h:308:3: note: expanded from macro '__compiletime_assert'
>> if (!(condition)) \
>>
>> vim +/opp +294 drivers/cpufreq/qcom-cpufreq-hw.c
>>
>> 275
>> 276 static void qcom_lmh_dcvs_notify(struct qcom_cpufreq_data *data)
>> 277 {
>> 278 unsigned long max_capacity, capacity, freq_hz, throttled_freq;
>> 279 struct cpufreq_policy *policy = data->policy;
>> 280 int cpu = cpumask_first(policy->cpus);
>> 281 struct device *dev = get_cpu_device(cpu);
>> 282 struct dev_pm_opp *opp;
>> 283 unsigned int freq;
>> 284
>> 285 /*
>> 286 * Get the h/w throttled frequency, normalize it using the
>> 287 * registered opp table and use it to calculate thermal pressure.
>> 288 */
>> 289 freq = qcom_lmh_get_throttle_freq(data);
>> 290 freq_hz = freq * HZ_PER_KHZ;
>> 291
>> 292 opp = dev_pm_opp_find_freq_floor(dev, &freq_hz);
>> 293 if (IS_ERR(opp) && PTR_ERR(opp) == -ERANGE)
>> > 294 opp = dev_pm_opp_find_freq_ceil(dev, &freq_hz);
>> 295
>> 296 throttled_freq = freq_hz / HZ_PER_KHZ;
>> 297
>> 298 /* Update thermal pressure */
>> 299
>> 300 max_capacity = arch_scale_cpu_capacity(cpu);
>> 301 capacity = mult_frac(max_capacity, throttled_freq, policy->cpuinfo.max_freq);
>> 302
>> 303 /* Don't pass boost capacity to scheduler */
>> 304 if (capacity > max_capacity)
>> 305 capacity = max_capacity;
>> 306
>> 307 arch_set_thermal_pressure(policy->cpus, max_capacity - capacity);
>> 308
>> 309 /*
>> 310 * In the unlikely case policy is unregistered do not enable
>> 311 * polling or h/w interrupt
>> 312 */
>> 313 mutex_lock(&data->throttle_lock);
>> 314 if (data->cancel_throttle)
>> 315 goto out;
>> 316
>> 317 /*
>> 318 * If h/w throttled frequency is higher than what cpufreq has requested
>> 319 * for, then stop polling and switch back to interrupt mechanism.
>> 320 */
>> 321 if (throttled_freq >= qcom_cpufreq_hw_get(cpu))
>> 322 enable_irq(data->throttle_irq);
>> 323 else
>> 324 mod_delayed_work(system_highpri_wq, &data->throttle_work,
>> 325 msecs_to_jiffies(10));
>> 326
>> 327 out:
>> 328 mutex_unlock(&data->throttle_lock);
>> 329 }
>> 330
>>
>> ---
>> 0-DAY CI Kernel Test Service, Intel Corporation
>> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
>
>
>
next prev parent reply other threads:[~2021-08-24 6:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-22 11:41 kernel test robot
2021-08-23 6:52 ` Viresh Kumar
2021-08-24 6:53 ` Chen, Rong A [this message]
2021-08-24 7:11 ` Viresh Kumar
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=38f16bcf-40bc-c400-ef64-da8e43b1135f@intel.com \
--to=rong.a.chen@intel.com \
--cc=clang-built-linux@googlegroups.com \
--cc=kbuild-all@lists.01.org \
--cc=linux-mm@kvack.org \
--cc=lkp@intel.com \
--cc=thara.gopinath@linaro.org \
--cc=viresh.kumar@linaro.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