Re: [RFC PATCH net-next] net: dsa: replace NETDEV_PRE_CHANGE_HWTSTAMP notifier with a stub

kernel test robot
2023-04-06T02:58:36Z

Hi Vladimir,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url: https://github.com/intel-lab-lkp/linux/commits/Vladimir-Oltean/net-dsa-replace-NETDEV_PRE_CHANGE_HWTSTAMP-notifier-with-a-stub/20230406-005302
patch link: https://lore.kernel.org/r/20230405165115.3744445-1-vladimir.oltean%40nxp.com
patch subject: [RFC PATCH net-next] net: dsa: replace NETDEV_PRE_CHANGE_HWTSTAMP notifier with a stub
config: arm-randconfig-r023-20230403 (https://download.01.org/0day-ci/archive/20230406/202304061058.ZYSqgL8r-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm cross compiling tool for clang build
# apt-get install binutils-arm-linux-gnueabi
# https://github.com/intel-lab-lkp/linux/commit/4788a6c004ab7f7210b1d27777e733eab85db17e
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Vladimir-Oltean/net-dsa-replace-NETDEV_PRE_CHANGE_HWTSTAMP-notifier-with-a-stub/20230406-005302
git checkout 4788a6c004ab7f7210b1d27777e733eab85db17e
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash net/dsa/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304061058.ZYSqgL8r-lkp@intel.com/

All warnings (new ones prefixed by >>):

In file included from net/dsa/stubs.c:7:
>> include/net/dsa_stubs.h:33:2: warning: variable 'err' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (dsa_stubs)
^~~~~~~~~~~~~~
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/net/dsa_stubs.h:38:9: note: uninitialized use occurs here
return err;
^~~
include/net/dsa_stubs.h:33:2: note: remove the 'if' if its condition is always true
if (dsa_stubs)
^~~~~~~~~~~~~~
include/linux/compiler.h:56:23: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
include/net/dsa_stubs.h:26:9: note: initialize the variable 'err' to silence this warning
int err;
^
= 0
1 warning generated.

vim +33 include/net/dsa_stubs.h

21
22 static inline int dsa_master_hwtstamp_validate(struct net_device *dev,
23 const struct kernel_hwtstamp_config *config,
24 struct netlink_ext_ack *extack)
25 {
26 int err;
27
28 if (!netdev_uses_dsa(dev))
29 return 0;
30
31 mutex_lock(&dsa_stubs_lock);
32
> 33 if (dsa_stubs)
34 err = dsa_stubs->master_hwtstamp_validate(dev, config, extack);
35
36 mutex_unlock(&dsa_stubs_lock);
37
38 return err;
39 }
40

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