[linux-next:master 12831/15164] kernel/bpf/percpu_freelist.c:176:17: sparse: sparse: context imbalance in '___pcpu_freelist_pop_nmi' - different lock contexts for basic block

[kernel test robot <lkp@intel.com>]

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CC: kbuild-all(a)lists.01.org
CC: Linux Memory Management List <linux-mm@kvack.org>
TO: Song Liu <songliubraving@fb.com>
CC: Daniel Borkmann <daniel@iogearbox.net>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   03d992bd2de6c7f2c9bbd4260ff104c0926ce3ff
commit: 39d8f0d1026a990604770a658708f5845f7dbec0 [12831/15164] bpf: Use raw_spin_trylock() for pcpu_freelist_push/pop in NMI
:::::: branch date: 7 hours ago
:::::: commit date: 10 days ago
config: ia64-randconfig-s032-20201015 (attached as .config)
compiler: ia64-linux-gcc (GCC) 9.3.0
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-rc1-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=39d8f0d1026a990604770a658708f5845f7dbec0
        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 39d8f0d1026a990604770a658708f5845f7dbec0
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=ia64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


"sparse warnings: (new ones prefixed by >>)"
>> kernel/bpf/percpu_freelist.c:176:17: sparse: sparse: context imbalance in '___pcpu_freelist_pop_nmi' - different lock contexts for basic block

vim +/___pcpu_freelist_pop_nmi +176 kernel/bpf/percpu_freelist.c

39d8f0d1026a990 Song Liu           2020-10-05  156  
39d8f0d1026a990 Song Liu           2020-10-05  157  static struct pcpu_freelist_node *
39d8f0d1026a990 Song Liu           2020-10-05  158  ___pcpu_freelist_pop_nmi(struct pcpu_freelist *s)
39d8f0d1026a990 Song Liu           2020-10-05  159  {
39d8f0d1026a990 Song Liu           2020-10-05  160  	struct pcpu_freelist_head *head;
39d8f0d1026a990 Song Liu           2020-10-05  161  	struct pcpu_freelist_node *node;
39d8f0d1026a990 Song Liu           2020-10-05  162  	int orig_cpu, cpu;
39d8f0d1026a990 Song Liu           2020-10-05  163  
39d8f0d1026a990 Song Liu           2020-10-05  164  	orig_cpu = cpu = raw_smp_processor_id();
39d8f0d1026a990 Song Liu           2020-10-05  165  	while (1) {
39d8f0d1026a990 Song Liu           2020-10-05  166  		head = per_cpu_ptr(s->freelist, cpu);
39d8f0d1026a990 Song Liu           2020-10-05  167  		if (raw_spin_trylock(&head->lock)) {
39d8f0d1026a990 Song Liu           2020-10-05  168  			node = head->first;
39d8f0d1026a990 Song Liu           2020-10-05  169  			if (node) {
39d8f0d1026a990 Song Liu           2020-10-05  170  				head->first = node->next;
39d8f0d1026a990 Song Liu           2020-10-05  171  				raw_spin_unlock(&head->lock);
39d8f0d1026a990 Song Liu           2020-10-05  172  				return node;
39d8f0d1026a990 Song Liu           2020-10-05  173  			}
39d8f0d1026a990 Song Liu           2020-10-05  174  			raw_spin_unlock(&head->lock);
39d8f0d1026a990 Song Liu           2020-10-05  175  		}
39d8f0d1026a990 Song Liu           2020-10-05 @176  		cpu = cpumask_next(cpu, cpu_possible_mask);
39d8f0d1026a990 Song Liu           2020-10-05  177  		if (cpu >= nr_cpu_ids)
39d8f0d1026a990 Song Liu           2020-10-05  178  			cpu = 0;
39d8f0d1026a990 Song Liu           2020-10-05  179  		if (cpu == orig_cpu)
39d8f0d1026a990 Song Liu           2020-10-05  180  			break;
39d8f0d1026a990 Song Liu           2020-10-05  181  	}
39d8f0d1026a990 Song Liu           2020-10-05  182  
39d8f0d1026a990 Song Liu           2020-10-05  183  	/* cannot pop from per cpu lists, try extralist */
39d8f0d1026a990 Song Liu           2020-10-05  184  	if (!raw_spin_trylock(&s->extralist.lock))
e19494edab82f55 Alexei Starovoitov 2016-03-07  185  		return NULL;
39d8f0d1026a990 Song Liu           2020-10-05  186  	node = s->extralist.first;
39d8f0d1026a990 Song Liu           2020-10-05  187  	if (node)
39d8f0d1026a990 Song Liu           2020-10-05  188  		s->extralist.first = node->next;
39d8f0d1026a990 Song Liu           2020-10-05  189  	raw_spin_unlock(&s->extralist.lock);
39d8f0d1026a990 Song Liu           2020-10-05  190  	return node;
e19494edab82f55 Alexei Starovoitov 2016-03-07  191  }
39d8f0d1026a990 Song Liu           2020-10-05  192  

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

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