tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 6b75d88fa81b122cce37ebf17428a849ccd3d0f1 commit: e188f3330a13df904d77003846eafd3edf99009d ARC: cmpxchg/xchg: rewrite as macros to make type safe date: 3 months ago config: arc-randconfig-s032-20211008 (attached as .config) compiler: arceb-elf-gcc (GCC) 11.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # apt-get install sparse # sparse version: v0.6.4-dirty # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout e188f3330a13df904d77003846eafd3edf99009d # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=arc SHELL=/bin/bash arch/arc/kernel/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) arch/arc/kernel/smp.c:39:20: sparse: sparse: symbol 'secondary_idle_tsk' was not declared. Should it be static? arch/arc/kernel/smp.c:142:6: sparse: sparse: symbol 'arc_platform_smp_wait_to_boot' was not declared. Should it be static? arch/arc/kernel/smp.c:164:6: sparse: sparse: symbol 'start_kernel_secondary' was not declared. Should it be static? arch/arc/kernel/smp.c:264:48: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected unsigned long [noderef] __percpu *ipi_data_ptr @@ got unsigned long * @@ arch/arc/kernel/smp.c:264:48: sparse: expected unsigned long [noderef] __percpu *ipi_data_ptr arch/arc/kernel/smp.c:264:48: sparse: got unsigned long * arch/arc/kernel/smp.c:279:18: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void const volatile *v @@ got unsigned long [noderef] __percpu *__ai_ptr @@ arch/arc/kernel/smp.c:279:18: sparse: expected void const volatile *v arch/arc/kernel/smp.c:279:18: sparse: got unsigned long [noderef] __percpu *__ai_ptr arch/arc/kernel/smp.c:277:29: sparse: sparse: cast removes address space '__percpu' of expression arch/arc/kernel/smp.c:362:13: sparse: sparse: symbol 'do_IPI' was not declared. Should it be static? arch/arc/kernel/smp.c:413:72: sparse: sparse: incorrect type in argument 4 (different address spaces) @@ expected void [noderef] __percpu *percpu_dev_id @@ got int *dev @@ arch/arc/kernel/smp.c:413:72: sparse: expected void [noderef] __percpu *percpu_dev_id arch/arc/kernel/smp.c:413:72: sparse: got int *dev vim +279 arch/arc/kernel/smp.c 41195d236e8445 Vineet Gupta 2013-01-18 261 ddf84433f411b6 Vineet Gupta 2013-11-25 262 static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg) 41195d236e8445 Vineet Gupta 2013-01-18 263 { f2a4aa5646687f Vineet Gupta 2013-11-26 264 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu); d8e8c7dda11f5d Vineet Gupta 2013-11-28 265 unsigned long old, new; 41195d236e8445 Vineet Gupta 2013-01-18 266 unsigned long flags; 41195d236e8445 Vineet Gupta 2013-01-18 267 f2a4aa5646687f Vineet Gupta 2013-11-26 268 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu); f2a4aa5646687f Vineet Gupta 2013-11-26 269 41195d236e8445 Vineet Gupta 2013-01-18 270 local_irq_save(flags); 41195d236e8445 Vineet Gupta 2013-01-18 271 d8e8c7dda11f5d Vineet Gupta 2013-11-28 272 /* d8e8c7dda11f5d Vineet Gupta 2013-11-28 273 * Atomically write new msg bit (in case others are writing too), d8e8c7dda11f5d Vineet Gupta 2013-11-28 274 * and read back old value d8e8c7dda11f5d Vineet Gupta 2013-11-28 275 */ d8e8c7dda11f5d Vineet Gupta 2013-11-28 276 do { 6aa7de059173a9 Mark Rutland 2017-10-23 277 new = old = READ_ONCE(*ipi_data_ptr); d8e8c7dda11f5d Vineet Gupta 2013-11-28 278 new |= 1U << msg; d8e8c7dda11f5d Vineet Gupta 2013-11-28 @279 } while (cmpxchg(ipi_data_ptr, old, new) != old); 41195d236e8445 Vineet Gupta 2013-01-18 280 d8e8c7dda11f5d Vineet Gupta 2013-11-28 281 /* d8e8c7dda11f5d Vineet Gupta 2013-11-28 282 * Call the platform specific IPI kick function, but avoid if possible: d8e8c7dda11f5d Vineet Gupta 2013-11-28 283 * Only do so if there's no pending msg from other concurrent sender(s). 82a423053eb3cf Changcheng Deng 2021-08-14 284 * Otherwise, receiver will see this msg as well when it takes the d8e8c7dda11f5d Vineet Gupta 2013-11-28 285 * IPI corresponding to that msg. This is true, even if it is already in d8e8c7dda11f5d Vineet Gupta 2013-11-28 286 * IPI handler, because !@old means it has not yet dequeued the msg(s) d8e8c7dda11f5d Vineet Gupta 2013-11-28 287 * so @new msg can be a free-loader d8e8c7dda11f5d Vineet Gupta 2013-11-28 288 */ d8e8c7dda11f5d Vineet Gupta 2013-11-28 289 if (plat_smp_ops.ipi_send && !old) ddf84433f411b6 Vineet Gupta 2013-11-25 290 plat_smp_ops.ipi_send(cpu); 41195d236e8445 Vineet Gupta 2013-01-18 291 41195d236e8445 Vineet Gupta 2013-01-18 292 local_irq_restore(flags); 41195d236e8445 Vineet Gupta 2013-01-18 293 } 41195d236e8445 Vineet Gupta 2013-01-18 294 :::::: The code at line 279 was first introduced by commit :::::: d8e8c7dda11f5d5cf90495f2e89d917a83509bc0 ARC: [SMP] optimize IPI send and receive :::::: TO: Vineet Gupta <vgupta(a)synopsys.com&gt; :::::: CC: Vineet Gupta <vgupta(a)synopsys.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org