diff mbox series

time: ntp: Remove unnecessary ‘-ENODEV’ values from err

Message ID	20230627182540.5243-1-zeming@nfschina.com
State	New
Headers	Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; From: Li zeming <zeming@nfschina.com> To: jstultz@google.com, tglx@linutronix.de, sboyd@kernel.org Cc: linux-kernel@vger.kernel.org, Li zeming <zeming@nfschina.com> Subject: [PATCH] =?utf-8?q?time=3A_ntp=3A_Remove_unnecessary_=E2=80=98-ENODE?= =?utf-8?q?V=E2=80=99_values_from_err?= Date: Wed, 28 Jun 2023 02:25:40 +0800 Message-Id: <20230627182540.5243-1-zeming@nfschina.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	time: ntp: Remove unnecessary ‘-ENODEV’ values from err \| time: ntp: Remove unnecessary ‘-ENODEV’ values from err

Commit Message

Li zeming June 27, 2023, 6:25 p.m. UTC

  err is assigned first, so it does not need to initialize the assignment.

Signed-off-by: Li zeming <zeming@nfschina.com>
---
 kernel/time/ntp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

kernel test robot June 26, 2023, 4:05 a.m. UTC | #1

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

kernel test robot June 26, 2023, 4:05 a.m. UTC | #2

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: i386-randconfig-i004-20230626 (https://download.01.org/0day-ci/archive/20230626/202306261141.5MEtBJtk-lkp@intel.com/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce: (https://download.01.org/0day-ci/archive/20230626/202306261141.5MEtBJtk-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/202306261141.5MEtBJtk-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/time/ntp.c:591:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (!rtc->ops || !rtc->ops->set_time)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/time/ntp.c:605:9: note: uninitialized use occurs here
           return err;
                  ^~~
   kernel/time/ntp.c:591:2: note: remove the 'if' if its condition is always false
           if (!rtc->ops || !rtc->ops->set_time)
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/time/ntp.c:591:6: warning: variable 'err' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
           if (!rtc->ops || !rtc->ops->set_time)
               ^~~~~~~~~
   kernel/time/ntp.c:605:9: note: uninitialized use occurs here
           return err;
                  ^~~
   kernel/time/ntp.c:591:6: note: remove the '||' if its condition is always false
           if (!rtc->ops || !rtc->ops->set_time)
               ^~~~~~~~~~~~
   kernel/time/ntp.c:585:9: note: initialize the variable 'err' to silence this warning
           int err;
                  ^
                   = 0
   2 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

Thomas Gleixner June 26, 2023, 8:53 p.m. UTC | #3

On Wed, Jun 28 2023 at 02:25, Li zeming wrote:
> err is assigned first, so it does not need to initialize the
> assignment.

I don't know how you or the broken tool you rely upon came to that
conclusion.

There is clearly an error exit path which proves you wrong.

Please look at your changes and compile them before posting. There are
existing tools which do a better job than that.

Thanks,

        tglx

diff mbox series

Patch

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 406dccb79c2b..3808bbf4db0c 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -582,7 +582,7 @@  static int update_rtc(struct timespec64 *to_set, unsigned long *offset_nsec)
 {
 	struct rtc_device *rtc;
 	struct rtc_time tm;
-	int err = -ENODEV;
+	int err;
 
 	rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE);
 	if (!rtc)