Messages in this thread | | | Subject | Re: [kbuild-all] Re: kernel/time/clocksource-wdtest.c:47:22: warning: signed shift result (0x27BC86B00) requires 35 bits to represent, but 'long' only has 32 bits | From | Rong Chen <> | Date | Mon, 5 Jul 2021 15:47:09 +0800 |
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On 7/5/21 1:43 AM, Paul E. McKenney wrote: > On Sun, Jul 04, 2021 at 05:42:36AM +0800, kernel test robot wrote: >> 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@intel.com> >> >> 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. > You have CONFIG_HZ_24=y and this test module assumes HZ > 100, as noted > just above the excerpt below: > > /* Assume HZ > 100. */ > #define JIFFIES_SHIFT 8 > > So this is expected behavior. > > Would it help if I gave that comment some teeth, for example, as > shown at the end of this email?
Hi Paul,
I have confirmed that the below change can avoid the warning.
Best Regards, Rong Chen
> > ------------------------------------------------------------------------ > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index e1856030fa66..8f0ad6e4183c 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -2573,6 +2573,7 @@ config TEST_FPU > config TEST_CLOCKSOURCE_WATCHDOG > tristate "Test clocksource watchdog in kernel space" > depends on CLOCKSOURCE_WATCHDOG > + depends on HZ >= 100 > help > Enable this option to create a kernel module that will trigger > a test of the clocksource watchdog. This module may be loaded > _______________________________________________ > kbuild-all mailing list -- kbuild-all@lists.01.org > To unsubscribe send an email to kbuild-all-leave@lists.01.org
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