[linux-next:master 8412/10077] arch/arc/kernel/smp.c:279:18: sparse: sparse: dereference of noderef expression

Wed Aug 25 04:22:06 PDT 2021

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   372b2891c15acbf7b90d948b08ac174bde77102c
commit: 3e7dd62254a2fb6ac472537cab3008cd3b6d6204 [8412/10077] ARC: cmpxchg/xchg: rewrite as macros to make type safe
config: arc-randconfig-s032-20210825 (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: v0.6.3-348-gf0e6938b-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=3e7dd62254a2fb6ac472537cab3008cd3b6d6204
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout 3e7dd62254a2fb6ac472537cab3008cd3b6d6204
        # 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 at intel.com>


sparse warnings: (new ones prefixed by >>)
   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: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
>> arch/arc/kernel/smp.c:279:18: sparse: sparse: dereference of noderef expression
>> arch/arc/kernel/smp.c:279:18: sparse: sparse: dereference of noderef expression

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).
427df45f7baac5 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 at synopsys.com>
:::::: CC: Vineet Gupta <vgupta at synopsys.com>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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