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Thu, 04 Dec 2025 21:57:17 +0800 Date: Thu, 4 Dec 2025 21:57:14 +0800 From: Feng Tang To: Andrew Morton Cc: kernel test robot , llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, Linux Memory Management List , Petr Mladek 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: <20251203144453.be34d189c5e6668ce2da06b3@linux-foundation.org> X-Rspamd-Queue-Id: DB8BC140014 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: gxwyiqrk9c6seg63ms3wozjygkemmkhy X-HE-Tag: 1764856643-756845 X-HE-Meta: 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 ARK2yvNG dGnFF7B9wmzqJ+Gh2pcXJljwKgUKMAkk7duO/vYLbsM/kvYmF4H4opa8yULTrzDqXdeDjmQt8LTyWn09sgpiMbwfIlOCz9BeZU3qF9fMBcG+60FRFZHfiIC6cAHl0q1BYboVs3APfA/9G2qGvKSYekgzl9pB8/j1GW/9K8LORmsS8uYJIkCa3a+vJWokaKCVSvrTu8AcBfvCtNhpTmdUmxg/b7ETWFPqbmiJYSj9dQFV+FbJyQLDCTXVUZ7hK3CsV+A0NUxoFmJAys5E2FcimLu5fBjXLPodogTvWJXX+VYzR/Oumklol5BPoq0bXq9TZvrh0HlnkjOB0WU/8GMelMFmroyQIfMAfxC35Fx88R23QZzDwMF+8PrlVZilg53WLooXGspWmOQepRJZfv8kl4W8eoaxlitzMYrziKLpf95cTqCg3DSLo9eeM5uHv4FWzqdB2R2rTEH3enSrSx15YegGT/5dkDmtrVi1jjOmhX3/sPpo= 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 Wed, Dec 03, 2025 at 02:44:53PM -0800, 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. Yes, it is a little weird. Logically the 'hardlockup_si_mask' should be under the CONFIG_HARDLOCKUP_DETECTOR, which is what my original patch did. I did a quick check, and there are 3 types of hardlockup detector: HARDLOCKUP_DETECTOR_PERF HARDLOCKUP_DETECTOR_BUDDY HARDLOCKUP_DETECTOR_ARCH IIUC, most archs will use the first 2 types, which will both select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER (lib/Kconfig.debug), which is kind of a _proxy_ to select SOFTLOCKUP_DETECTOR which needs hrtimer for its implementations. And only very few arch may chose the 3rd architecture specific implementation, which was in 0day bot's kernel config. In arch/powerpc/Kconfig select HAVE_HARDLOCKUP_DETECTOR_ARCH if PPC_BOOK3S_64 && SMP select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI In short, for most cases the hrtimer is used for soft/hard lockup detector. Thanks, Feng