[openeuler:OLK-6.6 12414/13217] arch/arm64/kvm/arm.c:138:7: warning: variable 'r' is used uninitialized whenever 'if' condition is false - Kernel

6 Aug 2024


      tree:   https://gitee.com/openeuler/kernel.git OLK-6.6
head:   d59a335bf0dd2aac9debe211a0a07fbeaf605fed
commit: 67e11ee6347c43a97e8987b03a5b3534cd8095d9 [12414/13217] kvm: add virtcca cvm host feature
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20240806/202408060639.d1BhjbnX-lkp@i...)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 423aec6573df4424f90555468128e17073ddc69e)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240806/202408060639.d1BhjbnX-lkp@i...)
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 lkp@intel.com
| Closes: https://lore.kernel.org/oe-kbuild-all/202408060639.d1BhjbnX-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from arch/arm64/kvm/arm.c:9:
   In file included from include/linux/entry-kvm.h:6:
   In file included from include/linux/resume_user_mode.h:8:
   In file included from include/linux/memcontrol.h:20:
   In file included from include/linux/mm.h:2242:
   include/linux/vmstat.h:508:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     508 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     509 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:515:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     515 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     516 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:522:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     522 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:527:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     527 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     528 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:536:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     536 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     537 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
...
...
arch/arm64/kvm/arm.c:138:7: warning: variable 'r' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
138 |                 if (static_branch_unlikely(&virtcca_cvm_is_available))
         |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/jump_label.h:504:40: note: expanded from macro 'static_branch_unlikely'
     504 | #define static_branch_unlikely(x)                                               \
         |                                                                                 ^
     505 | ({                                                                              \
         | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     506 |         bool branch;                                                            \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     507 |         if (__builtin_types_compatible_p(typeof(*x), struct static_key_true))   \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     508 |                 branch = arch_static_branch_jump(&(x)->key, false);             \
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     509 |         else if (__builtin_types_compatible_p(typeof(*x), struct static_key_false)) \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     510 |                 branch = arch_static_branch(&(x)->key, false);                  \
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     511 |         else                                                                    \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     512 |                 branch = ____wrong_branch_error();                              \
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     513 |         unlikely_notrace(branch);                                                       \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     514 | })
         | ~~
   arch/arm64/kvm/arm.c:147:9: note: uninitialized use occurs here
     147 |         return r;
         |                ^
   arch/arm64/kvm/arm.c:138:3: note: remove the 'if' if its condition is always true
     138 |                 if (static_branch_unlikely(&virtcca_cvm_is_available))
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     139 |                         r = kvm_cvm_enable_cap(kvm, cap);
   arch/arm64/kvm/arm.c:92:7: note: initialize the variable 'r' to silence this warning
      92 |         int r;
         |              ^
         |               = 0
   6 warnings generated.
--
   In file included from arch/arm64/kvm/tmi.c:6:
   In file included from arch/arm64/include/asm/kvm_tmi.h:8:
   In file included from include/linux/kvm_host.h:16:
   In file included from include/linux/mm.h:2242:
   include/linux/vmstat.h:508:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     508 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     509 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:515:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     515 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     516 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:522:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     522 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:527:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     527 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     528 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:536:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     536 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     537 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
...
...
arch/arm64/kvm/tmi.c:131:5: warning: no previous prototype for function 'tmi_tmm_inf_test' [-Wmissing-prototypes]
131 | u64 tmi_tmm_inf_test(u64 x1, u64 x2, u64 x3, u64 x4, u64 x5)
         |     ^
   arch/arm64/kvm/tmi.c:131:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     131 | u64 tmi_tmm_inf_test(u64 x1, u64 x2, u64 x3, u64 x4, u64 x5)
         | ^
         | static 
   6 warnings generated.
--
   In file included from arch/arm64/kvm/virtcca_cvm.c:5:
   In file included from include/linux/kvm_host.h:16:
   In file included from include/linux/mm.h:2242:
   include/linux/vmstat.h:508:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     508 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     509 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:515:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     515 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     516 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:522:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     522 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:527:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     527 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     528 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:536:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     536 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     537 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
...
...
arch/arm64/kvm/virtcca_cvm.c:70:6: warning: no previous prototype for function 'kvm_cvm_supports_sve' [-Wmissing-prototypes]
70 | bool kvm_cvm_supports_sve(void)
         |      ^
   arch/arm64/kvm/virtcca_cvm.c:70:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
      70 | bool kvm_cvm_supports_sve(void)
         | ^
         | static
...
...
arch/arm64/kvm/virtcca_cvm.c:75:6: warning: no previous prototype for function 'kvm_cvm_supports_pmu' [-Wmissing-prototypes]
75 | bool kvm_cvm_supports_pmu(void)
         |      ^
   arch/arm64/kvm/virtcca_cvm.c:75:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
      75 | bool kvm_cvm_supports_pmu(void)
         | ^
         | static
...
...
arch/arm64/kvm/virtcca_cvm.c:80:5: warning: no previous prototype for function 'kvm_cvm_ipa_limit' [-Wmissing-prototypes]
80 | u32 kvm_cvm_ipa_limit(void)
         |     ^
   arch/arm64/kvm/virtcca_cvm.c:80:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
      80 | u32 kvm_cvm_ipa_limit(void)
         | ^
         | static
...
...
arch/arm64/kvm/virtcca_cvm.c:85:5: warning: no previous prototype for function 'kvm_cvm_get_num_brps' [-Wmissing-prototypes]
85 | u32 kvm_cvm_get_num_brps(void)
         |     ^
   arch/arm64/kvm/virtcca_cvm.c:85:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
      85 | u32 kvm_cvm_get_num_brps(void)
         | ^
         | static
...
...
arch/arm64/kvm/virtcca_cvm.c:90:5: warning: no previous prototype for function 'kvm_cvm_get_num_wrps' [-Wmissing-prototypes]
90 | u32 kvm_cvm_get_num_wrps(void)
         |     ^
   arch/arm64/kvm/virtcca_cvm.c:90:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
      90 | u32 kvm_cvm_get_num_wrps(void)
         | ^
         | static
...
...
arch/arm64/kvm/virtcca_cvm.c:244:5: warning: no previous prototype for function 'kvm_cvm_create_ttt_levels' [-Wmissing-prototypes]
244 | int kvm_cvm_create_ttt_levels(struct kvm *kvm, struct virtcca_cvm *cvm,
         |     ^
   arch/arm64/kvm/virtcca_cvm.c:244:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     244 | int kvm_cvm_create_ttt_levels(struct kvm *kvm, struct virtcca_cvm *cvm,
         | ^
         | static
...
...
arch/arm64/kvm/virtcca_cvm.c:311:5: warning: no previous prototype for function 'kvm_cvm_populate_par_region' [-Wmissing-prototypes]
311 | int kvm_cvm_populate_par_region(struct kvm *kvm, u64 numa_set,
         |     ^
   arch/arm64/kvm/virtcca_cvm.c:311:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     311 | int kvm_cvm_populate_par_region(struct kvm *kvm, u64 numa_set,
         | ^
         | static 
   12 warnings generated.
vim +138 arch/arm64/kvm/arm.c
88	
    89	int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
    90				    struct kvm_enable_cap *cap)
    91	{
    92		int r;
    93		u64 new_cap;
    94	
    95		if (cap->flags)
    96			return -EINVAL;
    97	
    98		switch (cap->cap) {
    99		case KVM_CAP_ARM_NISV_TO_USER:
   100			r = 0;
   101			set_bit(KVM_ARCH_FLAG_RETURN_NISV_IO_ABORT_TO_USER,
   102				&kvm->arch.flags);
   103			break;
   104		case KVM_CAP_ARM_MTE:
   105			mutex_lock(&kvm->lock);
   106			if (!system_supports_mte() || kvm->created_vcpus) {
   107				r = -EINVAL;
   108			} else {
   109				r = 0;
   110				set_bit(KVM_ARCH_FLAG_MTE_ENABLED, &kvm->arch.flags);
   111			}
   112			mutex_unlock(&kvm->lock);
   113			break;
   114		case KVM_CAP_ARM_SYSTEM_SUSPEND:
   115			r = 0;
   116			set_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags);
   117			break;
   118		case KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE:
   119			new_cap = cap->args[0];
   120	
   121			mutex_lock(&kvm->slots_lock);
   122			/*
   123			 * To keep things simple, allow changing the chunk
   124			 * size only when no memory slots have been created.
   125			 */
   126			if (!kvm_are_all_memslots_empty(kvm)) {
   127				r = -EINVAL;
   128			} else if (new_cap && !kvm_is_block_size_supported(new_cap)) {
   129				r = -EINVAL;
   130			} else {
   131				r = 0;
   132				kvm->arch.mmu.split_page_chunk_size = new_cap;
   133			}
   134			mutex_unlock(&kvm->slots_lock);
   135			break;
   136	#ifdef CONFIG_HISI_VIRTCCA_HOST
   137		case KVM_CAP_ARM_TMM:
...
138			if (static_branch_unlikely(&virtcca_cvm_is_available))
139				r = kvm_cvm_enable_cap(kvm, cap);
   140			break;
   141	#endif
   142		default:
   143			r = -EINVAL;
   144			break;
   145		}
   146	
   147		return r;
   148	}
   149
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