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Thu, 04 Dec 2025 22:12:35 +0800 Date: Thu, 4 Dec 2025 22:12:32 +0800 From: Feng Tang To: Petr Mladek Cc: Andrew Morton , kernel test robot , llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, Linux Memory Management List Subject: Re: [linux-next:master 9966/13055] kernel/watchdog.c:74:22: warning: unused variable 'hardlockup_si_mask' Message-ID: References: <202512030920.NFKtekA7-lkp@intel.com> <20251203144453.be34d189c5e6668ce2da06b3@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 12A4140016 X-Stat-Signature: jcduownir3pbxks646jopmay9cj3m9ab X-Rspam-User: X-HE-Tag: 1764857560-590871 X-HE-Meta: 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 9eY/FuU2 o9/ouECnyDIGCD2WeSbQwrfiAsyAHAKMDHoGvqMWax6beDIK1phneRfMVlb/ug4XEcpoRjhSDacaDp38LTHavHZHCPXCaubztoiNbrvB6spO5i3k9nSvEQ6v8ZBY3MWbLx4BSXK4yF6lIo+36bBwj2q8s2KbwwqYYPtGMD+3KTOT3YTehP4DeTKyJl+HQvLmUiB612vfHx1rZWtTCChKh6lTm3Ob/9gtN65tF5eYXtbgldTLJh0xYv1e0oPhZJEqlDjW6xyeaBFY07x7+HK5sylCa3XrRxR4PnnAu2pH6dzG78qSv5gN8rI7HAtRJ8sMkKpwZ1+LO6jMSE0yVWQyWtOpVG7TuClrsOQoQYJNQJ4Wt/+Y+khO1i0PhM0JbzfrmOKu8urz89WOEp5oDs2ucEt31BybaFvjzHmwxuB8C0sYTvgCUHMONP6Jq+5PGCMX5PUKE9tuPJufNlaiX9Tali+6/hrUfOtCkwX5Y59zwICJvRaw= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Dec 04, 2025 at 02:38:42PM +0100, Petr Mladek wrote: > On Wed 2025-12-03 14:44:53, Andrew Morton wrote: > > On Wed, 3 Dec 2025 09:05:30 +0800 kernel test robot wrote: > > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > > head: 47b7b5e32bb7264b51b89186043e1ada4090b558 > > > commit: a9af76a78760717361cccc884dc649e30db61c8b [9966/13055] watchdog: add sys_info sysctls to dump sys info on system lockup > > > config: powerpc64-randconfig-002-20251203 (https://download.01.org/0day-ci/archive/20251203/202512030920.NFKtekA7-lkp@intel.com/config) > > > compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 734a912d0f025559fcf76bde9aaaeb0383c1625a) > > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251203/202512030920.NFKtekA7-lkp@intel.com/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 > > > | Closes: https://lore.kernel.org/oe-kbuild-all/202512030920.NFKtekA7-lkp@intel.com/ > > > > > > All warnings (new ones prefixed by >>): > > > > > > >> kernel/watchdog.c:74:22: warning: unused variable 'hardlockup_si_mask' [-Wunused-variable] > > > 74 | static unsigned long hardlockup_si_mask; > > > | ^~~~~~~~~~~~~~~~~~ > > > 1 warning generated. > > > > I'm testing the appended patch but it needs checking please. > > > > The comment for hardlockup_si_mask says > > > > * bitmask to control what kinds of system info to be printed when > > * hard lockup is detected, it could be task, memory, lock etc. > > * Refer include/linux/sys_info.h for detailed bit definition. > > > > but the variable depends on "COUNTS_HRTIMER". The comment doesn't > > mention hrtimers and I don't see why it should. Not sure what's going > > on here. > > Good point! It took me some time to understand it. > > So, powerpc implements its own watchog, see arch/powerpc/kernel/watchdog.c. > The watchdog is supported only by some powerpc platforms, see the > following line in arch/powerpc/Kconfig: > > select HAVE_HARDLOCKUP_DETECTOR_ARCH if PPC_BOOK3S_64 && SMP > > As a result, the test system could have the following in the config, > see https://download.01.org/0day-ci/archive/20251203/202512030920.NFKtekA7-lkp@intel.com/config > > CONFIG_HARDLOCKUP_DETECTOR=y > # CONFIG_HARDLOCKUP_DETECTOR_PERF is not set > # CONFIG_HARDLOCKUP_DETECTOR_BUDDY is not set > CONFIG_HARDLOCKUP_DETECTOR_ARCH=y > > And "COUNTS_HRTIMER" is not defined. Thanks for the check! Was working on a reply at the same time :) > > @@ -1250,6 +1250,7 @@ static const struct ctl_table watchdog_s > > .extra1 = SYSCTL_ZERO, > > .extra2 = SYSCTL_ONE, > > }, > > +#if defined(CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER) > > { > > .procname = "hardlockup_sys_info", > > .data = &hardlockup_si_mask, > > @@ -1257,6 +1258,7 @@ static const struct ctl_table watchdog_s > > .mode = 0644, > > .proc_handler = sysctl_sys_info_handler, > > }, > > +#endif > > #ifdef CONFIG_SMP > > { > > .procname = "hardlockup_all_cpu_backtrace", > > _ > > This patch makes some sense because the arch-specific watchdog does > not support the sys_info interface. And it is better than nothing. > definitely. > > A better solution would be export the variable and handle it > in arch/powerpc/kernel/watchdog.c. Yep! > It seems that powerpc is the only architecture which could define > HAVE_HARDLOCKUP_DETECTOR_ARCH. > > Feng, would you have time to look at it? Sure. Thanks, Feng