LinuxLists.cc - [PATCH] time: ntp: Remove unnecessary ‘-ENODEV’ values from err

2023-06-26 02:39:19

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

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

Signed-off-by: Li zeming <[email protected]>
---
kernel/time/ntp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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)
--
2.18.2

2023-06-26 04:30:03

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH] time: ntp: Remove un necessary ‘-ENODEV’ values from err

2023-06-26 04:30:36

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH] time: ntp: Remove un necessary ‘-ENODEV’ values from err

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/[email protected]/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230626/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

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

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

2023-06-26 21:50:29

by Thomas Gleixner

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

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