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Date:   Mon, 26 Jun 2023 12:05:52 +0800
From:   kernel test robot <lkp@intel.com>
To:     Li zeming <zeming@nfschina.com>, jstultz@google.com,
        tglx@linutronix.de, sboyd@kernel.org
Cc:     llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
        linux-kernel@vger.kernel.org, Li zeming <zeming@nfschina.com>
Subject: Re: [PATCH] time: ntp: Remove =?utf-8?Q?un?=
 =?utf-8?B?bmVjZXNzYXJ5IOKAmC1FTk9ERVbigJk=?= values from err
Message-ID: <202306261146.21X5CDd9-lkp@intel.com>
References: <20230627182540.5243-1-zeming@nfschina.com>
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In-Reply-To: <20230627182540.5243-1-zeming@nfschina.com>
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Hi Li,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tip/timers/core]
[also build test WARNING on linus/master v6.4 next-20230623]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Li-zeming/time-ntp-Remove-unnecessary-ENODEV-values-from-err/20230626-095508
base:   tip/timers/core
patch link:    https://lore.kernel.org/r/20230627182540.5243-1-zeming%40nfschina.com
patch subject: [PATCH] time: ntp: Remove unnecessary ‘-ENODEV’ values from err
config: hexagon-randconfig-r045-20230626 (https://download.01.org/0day-ci/archive/20230626/202306261146.21X5CDd9-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230626/202306261146.21X5CDd9-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306261146.21X5CDd9-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from kernel/time/ntp.c:10:
   In file included from include/linux/clocksource.h:22:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from kernel/time/ntp.c:10:
   In file included from include/linux/clocksource.h:22:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from kernel/time/ntp.c:10:
   In file included from include/linux/clocksource.h:22:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
>> kernel/time/ntp.c:591:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
     591 |         if (!rtc->ops || !rtc->ops->set_time)
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/time/ntp.c:605:9: note: uninitialized use occurs here
     605 |         return err;
         |                ^~~
   kernel/time/ntp.c:591:2: note: remove the 'if' if its condition is always false
     591 |         if (!rtc->ops || !rtc->ops->set_time)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     592 |                 goto out_close;
         | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/time/ntp.c:591:6: warning: variable 'err' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
     591 |         if (!rtc->ops || !rtc->ops->set_time)
         |             ^~~~~~~~~
   kernel/time/ntp.c:605:9: note: uninitialized use occurs here
     605 |         return err;
         |                ^~~
   kernel/time/ntp.c:591:6: note: remove the '||' if its condition is always false
     591 |         if (!rtc->ops || !rtc->ops->set_time)
         |             ^~~~~~~~~~~~
   kernel/time/ntp.c:585:9: note: initialize the variable 'err' to silence this warning
     585 |         int err;
         |                ^
         |                 = 0
   8 warnings generated.


vim +591 kernel/time/ntp.c

76e87d96b30b5f Thomas Gleixner 2020-12-06  578  
33e62e832384c8 Thomas Gleixner 2020-12-06  579  #ifdef CONFIG_RTC_SYSTOHC
76e87d96b30b5f Thomas Gleixner 2020-12-06  580  /* Save NTP synchronized time to the RTC */
76e87d96b30b5f Thomas Gleixner 2020-12-06  581  static int update_rtc(struct timespec64 *to_set, unsigned long *offset_nsec)
33e62e832384c8 Thomas Gleixner 2020-12-06  582  {
33e62e832384c8 Thomas Gleixner 2020-12-06  583  	struct rtc_device *rtc;
33e62e832384c8 Thomas Gleixner 2020-12-06  584  	struct rtc_time tm;
7c397afa918b1a Li zeming       2023-06-28  585  	int err;
33e62e832384c8 Thomas Gleixner 2020-12-06  586  
33e62e832384c8 Thomas Gleixner 2020-12-06  587  	rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE);
33e62e832384c8 Thomas Gleixner 2020-12-06  588  	if (!rtc)
76e87d96b30b5f Thomas Gleixner 2020-12-06  589  		return -ENODEV;
33e62e832384c8 Thomas Gleixner 2020-12-06  590  
33e62e832384c8 Thomas Gleixner 2020-12-06 @591  	if (!rtc->ops || !rtc->ops->set_time)
33e62e832384c8 Thomas Gleixner 2020-12-06  592  		goto out_close;
33e62e832384c8 Thomas Gleixner 2020-12-06  593  
76e87d96b30b5f Thomas Gleixner 2020-12-06  594  	/* First call might not have the correct offset */
76e87d96b30b5f Thomas Gleixner 2020-12-06  595  	if (*offset_nsec == rtc->set_offset_nsec) {
76e87d96b30b5f Thomas Gleixner 2020-12-06  596  		rtc_time64_to_tm(to_set->tv_sec, &tm);
76e87d96b30b5f Thomas Gleixner 2020-12-06  597  		err = rtc_set_time(rtc, &tm);
76e87d96b30b5f Thomas Gleixner 2020-12-06  598  	} else {
76e87d96b30b5f Thomas Gleixner 2020-12-06  599  		/* Store the update offset and let the caller try again */
69eca258c85000 Thomas Gleixner 2020-12-06  600  		*offset_nsec = rtc->set_offset_nsec;
76e87d96b30b5f Thomas Gleixner 2020-12-06  601  		err = -EAGAIN;
33e62e832384c8 Thomas Gleixner 2020-12-06  602  	}
33e62e832384c8 Thomas Gleixner 2020-12-06  603  out_close:
33e62e832384c8 Thomas Gleixner 2020-12-06  604  	rtc_class_close(rtc);
33e62e832384c8 Thomas Gleixner 2020-12-06  605  	return err;
33e62e832384c8 Thomas Gleixner 2020-12-06  606  }
33e62e832384c8 Thomas Gleixner 2020-12-06  607  #else
76e87d96b30b5f Thomas Gleixner 2020-12-06  608  static inline int update_rtc(struct timespec64 *to_set, unsigned long *offset_nsec)
3c00a1fe8496ff Xunlei Pang     2015-04-01  609  {
926617889dc838 Arnd Bergmann   2018-08-14  610  	return -ENODEV;
3c00a1fe8496ff Xunlei Pang     2015-04-01  611  }
3c00a1fe8496ff Xunlei Pang     2015-04-01  612  #endif
3c00a1fe8496ff Xunlei Pang     2015-04-01  613  

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