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a="23316492" X-IronPort-AV: E=Sophos;i="6.10,178,1719903600"; d="scan'208";a="23316492" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2024 13:54:33 -0700 X-CSE-ConnectionGUID: rMHbSxDmQSaT0vo36GTR1Q== X-CSE-MsgGUID: xxLRM9N0QDCGDGVQ3KiQFw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,178,1719903600"; d="scan'208";a="66789376" Received: from lkp-server01.sh.intel.com (HELO 9a732dc145d3) ([10.239.97.150]) by fmviesa003.fm.intel.com with ESMTP; 26 Aug 2024 13:54:29 -0700 Received: from kbuild by 9a732dc145d3 with local (Exim 4.96) (envelope-from ) id 1sigjL-000Hag-0H; Mon, 26 Aug 2024 20:54:27 +0000 Date: Tue, 27 Aug 2024 04:53:28 +0800 From: kernel test robot To: Ahmed Ehab , linux-kernel@vger.kernel.org Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [PATCH] Refactor switch_mm_cid() to avoid unnecessary checks Message-ID: <202408270315.58WsW5Fq-lkp@intel.com> References: <20240824223132.11925-1-bottaawesome633@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel-mentees@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240824223132.11925-1-bottaawesome633@gmail.com> Hi Ahmed, kernel test robot noticed the following build errors: [auto build test ERROR on tip/sched/core] [also build test ERROR on linus/master v6.11-rc5 next-20240826] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Ahmed-Ehab/Refactor-switch_mm_cid-to-avoid-unnecessary-checks/20240826-153216 base: tip/sched/core patch link: https://lore.kernel.org/r/20240824223132.11925-1-bottaawesome633%40gmail.com patch subject: [PATCH] Refactor switch_mm_cid() to avoid unnecessary checks config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20240827/202408270315.58WsW5Fq-lkp@intel.com/config) compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 08e5a1de8227512d4774a534b91cb2353cef6284) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240827/202408270315.58WsW5Fq-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/202408270315.58WsW5Fq-lkp@intel.com/ All errors (new ones prefixed by >>): In file included from kernel/sched/core.c:10: In file included from include/linux/highmem.h:10: In file included from include/linux/mm.h:2228: include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion] 514 | return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_" | ~~~~~~~~~~~ ^ ~~~ In file included from kernel/sched/core.c:34: In file included from include/linux/sched/isolation.h:7: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:22: In file included from arch/s390/include/asm/io.h:93: include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 548 | val = __raw_readb(PCI_IOBASE + addr); | ~~~~~~~~~~ ^ include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 561 | val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); | ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu' 37 | #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x)) | ^ include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16' 102 | #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) | ^ In file included from kernel/sched/core.c:34: In file included from include/linux/sched/isolation.h:7: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:22: In file included from arch/s390/include/asm/io.h:93: include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 574 | val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); | ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu' 35 | #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) | ^ include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32' 115 | #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) | ^ In file included from kernel/sched/core.c:34: In file included from include/linux/sched/isolation.h:7: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:22: In file included from arch/s390/include/asm/io.h:93: include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 585 | __raw_writeb(value, PCI_IOBASE + addr); | ~~~~~~~~~~ ^ include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 595 | __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); | ~~~~~~~~~~ ^ include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 605 | __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); | ~~~~~~~~~~ ^ include/asm-generic/io.h:693:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 693 | readsb(PCI_IOBASE + addr, buffer, count); | ~~~~~~~~~~ ^ include/asm-generic/io.h:701:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 701 | readsw(PCI_IOBASE + addr, buffer, count); | ~~~~~~~~~~ ^ include/asm-generic/io.h:709:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 709 | readsl(PCI_IOBASE + addr, buffer, count); | ~~~~~~~~~~ ^ include/asm-generic/io.h:718:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 718 | writesb(PCI_IOBASE + addr, buffer, count); | ~~~~~~~~~~ ^ include/asm-generic/io.h:727:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 727 | writesw(PCI_IOBASE + addr, buffer, count); | ~~~~~~~~~~ ^ include/asm-generic/io.h:736:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 736 | writesl(PCI_IOBASE + addr, buffer, count); | ~~~~~~~~~~ ^ >> kernel/sched/core.c:5232:4: error: call to undeclared function 'switch_mm_cid_from_user_to_kernel'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 5232 | switch_mm_cid_from_user_to_kernel(rq, prev, next); | ^ >> kernel/sched/core.c:5257:4: error: call to undeclared function 'switch_mm_cid_from_kernel_to_user'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 5257 | switch_mm_cid_from_kernel_to_user(rq, prev, next); | ^ >> kernel/sched/core.c:5259:4: error: call to undeclared function 'switch_mm_cid_from_user_to_user'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 5259 | switch_mm_cid_from_user_to_user(rq, prev, next); | ^ 13 warnings and 3 errors generated. vim +/switch_mm_cid_from_user_to_kernel +5232 kernel/sched/core.c 5199 5200 /* 5201 * context_switch - switch to the new MM and the new thread's register state. 5202 */ 5203 static __always_inline struct rq * 5204 context_switch(struct rq *rq, struct task_struct *prev, 5205 struct task_struct *next, struct rq_flags *rf) 5206 { 5207 prepare_task_switch(rq, prev, next); 5208 5209 /* 5210 * For paravirt, this is coupled with an exit in switch_to to 5211 * combine the page table reload and the switch backend into 5212 * one hypercall. 5213 */ 5214 arch_start_context_switch(prev); 5215 5216 /* 5217 * kernel -> kernel lazy + transfer active 5218 * user -> kernel lazy + mmgrab_lazy_tlb() active 5219 * 5220 * kernel -> user switch + mmdrop_lazy_tlb() active 5221 * user -> user switch 5222 * 5223 * switch_mm_cid() needs to be updated if the barriers provided 5224 * by context_switch() are modified. 5225 */ 5226 if (!next->mm) { // to kernel 5227 enter_lazy_tlb(prev->active_mm, next); 5228 5229 next->active_mm = prev->active_mm; 5230 if (prev->mm) { // from user 5231 mmgrab_lazy_tlb(prev->active_mm); > 5232 switch_mm_cid_from_user_to_kernel(rq, prev, next); 5233 } 5234 else 5235 /* 5236 * kernel -> kernel transition does not change rq->curr->mm 5237 * state. It stays NULL. 5238 */ 5239 prev->active_mm = NULL; 5240 } else { // to user 5241 membarrier_switch_mm(rq, prev->active_mm, next->mm); 5242 /* 5243 * sys_membarrier() requires an smp_mb() between setting 5244 * rq->curr / membarrier_switch_mm() and returning to userspace. 5245 * 5246 * The below provides this either through switch_mm(), or in 5247 * case 'prev->active_mm == next->mm' through 5248 * finish_task_switch()'s mmdrop(). 5249 */ 5250 switch_mm_irqs_off(prev->active_mm, next->mm, next); 5251 lru_gen_use_mm(next->mm); 5252 5253 if (!prev->mm) { // from kernel 5254 /* will mmdrop_lazy_tlb() in finish_task_switch(). */ 5255 rq->prev_mm = prev->active_mm; 5256 prev->active_mm = NULL; > 5257 switch_mm_cid_from_kernel_to_user(rq, prev, next); 5258 } else > 5259 switch_mm_cid_from_user_to_user(rq, prev, next); 5260 } 5261 5262 prepare_lock_switch(rq, next, rf); 5263 5264 /* Here we just switch the register state and the stack. */ 5265 switch_to(prev, next, prev); 5266 barrier(); 5267 5268 return finish_task_switch(prev); 5269 } 5270 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki