Re: [PATCH] time: ntp: Remove unnecessary ‘-ENODEV’ values from err

From: kernel test robot
Date: Mon Jun 26 2023 - 00:06:33 EST


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@xxxxxxxxx/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@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306261146.21X5CDd9-lkp@xxxxxxxxx/

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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