Re: [PATCH] kernel: time: clocksource: Remove unnecessary ‘0’ values from ret
From: kernel test robot
Date: Sun Aug 06 2023 - 23:29:53 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 v6.5-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@xxxxxxxxx/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@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/202308071105.lWPLR4Kr-lkp@xxxxxxxxx/
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
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