Hi, On Mon, Apr 20, 2020 at 11:22:09AM +0200, Michał Mirosław wrote: > On Tue, Apr 07, 2020 at 11:13:50AM -0700, Nick Desaulniers wrote: > > On Sat, Apr 4, 2020 at 6:53 PM kbuild test robot <[email protected]> wrote: > > > > > > Hi "Michał, > > > > > > I love your patch! Perhaps something to improve: > > > > > > [auto build test WARNING on power-supply/for-next] > > > [also build test WARNING on hwmon/hwmon-next linus/master v5.6 > > > next-20200404] > > > [if your patch is applied to the wrong git tree, please drop us a note to > > > help > > > improve the system. BTW, we also suggest to use '--base' option to > > > specify the > > > base tree in git format-patch, please see > > > https://stackoverflow.com/a/37406982] > > > > > > url: > > > https://github.com/0day-ci/linux/commits/Micha-Miros-aw/extensions-and-fixes/20200405-044024 > > > base: > > > https://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply.git > > > for-next > > > config: x86_64-randconfig-b002-20200405 (attached as .config) > > > compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project > > > 62f3a9650a9f289a07a5f480764fb655178c2334) > > > reproduce: > > > wget > > > https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross > > > -O ~/bin/make.cross > > > chmod +x ~/bin/make.cross > > > # save the attached .config to linux build tree > > > COMPILER=clang make.cross ARCH=x86_64 > > > > > > If you fix the issue, kindly add following tag as appropriate > > > Reported-by: kbuild test robot <[email protected]> > > > > > > All warnings (new ones prefixed by >>): > > > > > > >> drivers/power/supply/power_supply_hwmon.o: warning: objtool: > > > >> power_supply_hwmon_read_string() falls through to next function > > > >> power_supply_hwmon_write() > > > > I'm guessing this is from the unreachable: > > https://github.com/0day-ci/linux/commit/b8b2d14ca46ca54257f55c9af58ea25695b9ee36 > > I'll need to play with this some more as I couldn't reproduce with a > > simplified test case, but looks like a compiler bug. Filed > > https://github.com/ClangBuiltLinux/linux/issues/978 for me to track. > > Hi, > > For gcc this is bug 51513 [1]. This does not affect correctness of the > code, so I wonder if we should/need be trying to work around it. > > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51513
Yes, we need to work around it for now. If I understand the situation
correctly, a simple workaround would be:
default:
/*
* unreachable, but not explicitly marked because this triggers
* a compiler bug in gcc and llvm:
*
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51513
* https://github.com/ClangBuiltLinux/linux/issues/978
*/
break;
-- Sebastian
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