kernel/time/clocksource-wdtest.c:47:22: warning: signed shift result (0x27BC86B00) requires 35 bits to represent, but 'long' only has 32 bits

From: kernel test robot
Date: Sat Jul 03 2021 - 17:42:54 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 303392fd5c160822bf778270b28ec5ea50cab2b4
commit: 1253b9b87e42ab6a3d5c2cb27af2bdd67d7e50ff clocksource: Provide kernel module to test clocksource watchdog
date: 11 days ago
config: mips-randconfig-r015-20210702 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 9eb613b2de3163686b1a4bd1160f15ac56a4b083)
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 mips cross compiling tool for clang build
# apt-get install binutils-mips-linux-gnu
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1253b9b87e42ab6a3d5c2cb27af2bdd67d7e50ff
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 1253b9b87e42ab6a3d5c2cb27af2bdd67d7e50ff
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> kernel/time/clocksource-wdtest.c:47:22: warning: signed shift result (0x27BC86B00) requires 35 bits to represent, but 'long' only has 32 bits [-Wshift-overflow]
.mult = TICK_NSEC << JIFFIES_SHIFT, /* details above */
~~~~~~~~~ ^ ~~~~~~~~~~~~~
1 warning generated.


vim +/long +47 kernel/time/clocksource-wdtest.c

39
40 static struct clocksource clocksource_wdtest_jiffies = {
41 .name = "wdtest-jiffies",
42 .rating = 1, /* lowest valid rating*/
43 .uncertainty_margin = TICK_NSEC,
44 .read = wdtest_jiffies_read,
45 .mask = CLOCKSOURCE_MASK(32),
46 .flags = CLOCK_SOURCE_MUST_VERIFY,
> 47 .mult = TICK_NSEC << JIFFIES_SHIFT, /* details above */
48 .shift = JIFFIES_SHIFT,
49 .max_cycles = 10,
50 };
51

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

Attachment: .config.gz
Description: application/gzip