* Re: [PATCH] kernel: time: clocksource: Remove unnecessary ‘0’ values from ret
2023-08-08 17:36 [PATCH] kernel: time: clocksource: Remove unnecessary ‘0’ values from ret Li zeming
@ 2023-08-07 3:29 ` kernel test robot
2023-08-27 18:11 ` Thomas Gleixner
1 sibling, 0 replies; 3+ messages in thread
From: kernel test robot @ 2023-08-07 3:29 UTC (permalink / raw)
To: Li zeming, jstultz, tglx, sboyd
Cc: llvm, oe-kbuild-all, linux-kernel, Li zeming
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 v6.5-rc5 next-20230804]
[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/kernel-time-clocksource-Remove-unnecessary-0-values-from-ret/20230807-090629
base: tip/timers/core
patch link: https://lore.kernel.org/r/20230808173611.3066-1-zeming%40nfschina.com
patch subject: [PATCH] kernel: time: clocksource: Remove unnecessary ‘0’ values from ret
config: um-allnoconfig (https://download.01.org/0day-ci/archive/20230807/202308071105.lWPLR4Kr-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/20230807/202308071105.lWPLR4Kr-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/202308071105.lWPLR4Kr-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from kernel/time/clocksource.c:11:
In file included from include/linux/clocksource.h:22:
In file included from arch/um/include/asm/io.h:24:
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/clocksource.c:11:
In file included from include/linux/clocksource.h:22:
In file included from arch/um/include/asm/io.h:24:
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/clocksource.c:11:
In file included from include/linux/clocksource.h:22:
In file included from arch/um/include/asm/io.h:24:
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);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
692 | readsb(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
700 | readsw(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
708 | readsl(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
717 | writesb(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
726 | writesw(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
735 | writesl(PCI_IOBASE + addr, buffer, count);
| ~~~~~~~~~~ ^
>> kernel/time/clocksource.c:1295:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
1295 | if (!list_empty(&cs->list))
| ^~~~~~~~~~~~~~~~~~~~~~
kernel/time/clocksource.c:1298:9: note: uninitialized use occurs here
1298 | return ret;
| ^~~
kernel/time/clocksource.c:1295:2: note: remove the 'if' if its condition is always true
1295 | if (!list_empty(&cs->list))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
1296 | ret = clocksource_unbind(cs);
| ~~~~~~~~~~~~~~~~
kernel/time/clocksource.c:1292:9: note: initialize the variable 'ret' to silence this warning
1292 | int ret;
| ^
| = 0
13 warnings generated.
vim +1295 kernel/time/clocksource.c
7eaeb34305dee2 Thomas Gleixner 2013-04-25 1285
4713e22ce81eb8 Thomas Gleixner 2008-01-30 1286 /**
4713e22ce81eb8 Thomas Gleixner 2008-01-30 1287 * clocksource_unregister - remove a registered clocksource
b1b73d095084e7 Kusanagi Kouichi 2011-12-19 1288 * @cs: clocksource to be unregistered
4713e22ce81eb8 Thomas Gleixner 2008-01-30 1289 */
a89c7edbe7d7aa Thomas Gleixner 2013-04-25 1290 int clocksource_unregister(struct clocksource *cs)
4713e22ce81eb8 Thomas Gleixner 2008-01-30 1291 {
1c69718b036413 Li zeming 2023-08-09 1292 int ret;
a89c7edbe7d7aa Thomas Gleixner 2013-04-25 1293
75c5158f70c065 Martin Schwidefsky 2009-08-14 1294 mutex_lock(&clocksource_mutex);
a89c7edbe7d7aa Thomas Gleixner 2013-04-25 @1295 if (!list_empty(&cs->list))
a89c7edbe7d7aa Thomas Gleixner 2013-04-25 1296 ret = clocksource_unbind(cs);
75c5158f70c065 Martin Schwidefsky 2009-08-14 1297 mutex_unlock(&clocksource_mutex);
a89c7edbe7d7aa Thomas Gleixner 2013-04-25 1298 return ret;
4713e22ce81eb8 Thomas Gleixner 2008-01-30 1299 }
fb63a0ebe615fb Martin Schwidefsky 2009-08-14 1300 EXPORT_SYMBOL(clocksource_unregister);
4713e22ce81eb8 Thomas Gleixner 2008-01-30 1301
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] kernel: time: clocksource: Remove unnecessary ‘0’ values from ret
2023-08-08 17:36 [PATCH] kernel: time: clocksource: Remove unnecessary ‘0’ values from ret Li zeming
2023-08-07 3:29 ` kernel test robot
@ 2023-08-27 18:11 ` Thomas Gleixner
1 sibling, 0 replies; 3+ messages in thread
From: Thomas Gleixner @ 2023-08-27 18:11 UTC (permalink / raw)
To: Li zeming, jstultz, sboyd; +Cc: linux-kernel, Li zeming
On Wed, Aug 09 2023 at 01:36, Li zeming wrote:
> ret is assigned first, so it does not need to initialize the
> assignment.
> Signed-off-by: Li zeming <zeming@nfschina.com>
> ---
> kernel/time/clocksource.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> index 91836b727cef..b4ad38812ef7 100644
> --- a/kernel/time/clocksource.c
> +++ b/kernel/time/clocksource.c
> @@ -1289,7 +1289,7 @@ static int clocksource_unbind(struct clocksource *cs)
> */
> int clocksource_unregister(struct clocksource *cs)
> {
> - int ret = 0;
> + int ret;
>
> mutex_lock(&clocksource_mutex);
> if (!list_empty(&cs->list))
ret is only assigned a value when cs->list is not empty.
Can you please fix your analyzer or at least validate by inspection
whether your analyzer is correct?
While at it, please follow the instructions at:
https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#patch-submission-notes
Thanks,
tglx
^ permalink raw reply [flat|nested] 3+ messages in thread