linux-kernel - Re: [PATCH -next] PM / OPP: Fix crash seen if CPU clock has no voltage regulator

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Date:	Tue, 16 Feb 2016 08:17:55 +0800
From:	kbuild test robot <lkp@...el.com>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	kbuild-all@...org, Viresh Kumar <vireshk@...nel.org>,
	Nishanth Menon <nm@...com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
	Viresh Kumar <viresh.kumar@...aro.org>
Subject: Re: [PATCH -next] PM / OPP: Fix crash seen if CPU clock has no
 voltage regulator

Hi Jon,

[auto build test WARNING on next-20160215]

url:    https://github.com/0day-ci/linux/commits/Jon-Hunter/PM-OPP-Fix-NULL-pointer-dereference-crash-when-setting-the-OPP/20160215-220238
config: x86_64-randconfig-s0-02160737 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
>> drivers/base/power/opp/core.c:603:38: warning: 'ou_volt_max' may be used uninitialized in this function [-Wmaybe-uninitialized]
     unsigned long ou_volt, ou_volt_min, ou_volt_max;
                                         ^
>> drivers/base/power/opp/core.c:603:25: warning: 'ou_volt_min' may be used uninitialized in this function [-Wmaybe-uninitialized]
     unsigned long ou_volt, ou_volt_min, ou_volt_max;
                            ^
>> drivers/base/power/opp/core.c:603:16: warning: 'ou_volt' may be used uninitialized in this function [-Wmaybe-uninitialized]
     unsigned long ou_volt, ou_volt_min, ou_volt_max;
                   ^

vim +/ou_volt_max +603 drivers/base/power/opp/core.c

6a0712f6 Viresh Kumar 2016-02-09  587   * @dev:	 device for which we do this operation
6a0712f6 Viresh Kumar 2016-02-09  588   * @target_freq: frequency to achieve
6a0712f6 Viresh Kumar 2016-02-09  589   *
6a0712f6 Viresh Kumar 2016-02-09  590   * This configures the power-supplies and clock source to the levels specified
6a0712f6 Viresh Kumar 2016-02-09  591   * by the OPP corresponding to the target_freq.
6a0712f6 Viresh Kumar 2016-02-09  592   *
6a0712f6 Viresh Kumar 2016-02-09  593   * Locking: This function takes rcu_read_lock().
6a0712f6 Viresh Kumar 2016-02-09  594   */
6a0712f6 Viresh Kumar 2016-02-09  595  int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
6a0712f6 Viresh Kumar 2016-02-09  596  {
6a0712f6 Viresh Kumar 2016-02-09  597  	struct device_opp *dev_opp;
6a0712f6 Viresh Kumar 2016-02-09  598  	struct dev_pm_opp *old_opp, *opp;
6a0712f6 Viresh Kumar 2016-02-09  599  	struct regulator *reg;
6a0712f6 Viresh Kumar 2016-02-09  600  	struct clk *clk;
6a0712f6 Viresh Kumar 2016-02-09  601  	unsigned long freq, old_freq;
6a0712f6 Viresh Kumar 2016-02-09  602  	unsigned long u_volt, u_volt_min, u_volt_max;
6a0712f6 Viresh Kumar 2016-02-09 @603  	unsigned long ou_volt, ou_volt_min, ou_volt_max;
6a0712f6 Viresh Kumar 2016-02-09  604  	int ret;
6a0712f6 Viresh Kumar 2016-02-09  605  
6a0712f6 Viresh Kumar 2016-02-09  606  	if (unlikely(!target_freq)) {
6a0712f6 Viresh Kumar 2016-02-09  607  		dev_err(dev, "%s: Invalid target frequency %lu\n", __func__,
6a0712f6 Viresh Kumar 2016-02-09  608  			target_freq);
6a0712f6 Viresh Kumar 2016-02-09  609  		return -EINVAL;
6a0712f6 Viresh Kumar 2016-02-09  610  	}
6a0712f6 Viresh Kumar 2016-02-09  611  

:::::: The code at line 603 was first introduced by commit
:::::: 6a0712f6f199e737aa5913d28ec4bd3a25de9660 PM / OPP: Add dev_pm_opp_set_rate()

:::::: TO: Viresh Kumar <viresh.kumar@...aro.org>
:::::: CC: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

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Download attachment ".config.gz" of type "application/octet-stream" (23003 bytes)