Hi Paolo, FYI, the error/warning still remains. tree: https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS head: eabd480503b5c662a59778c9fa8c1a8f611d724e commit: 5694b2e450d4ad76c3314ad8ac73025bc616930e [1730/1730] kvm: make KVM_CAP_ENABLE_CAP_VM architecture agnostic config: arm64-randconfig-001-20250714 (https://download.01.org/0day-ci/archive/20250716/202507160405.SS3T4FhD-lkp@i...) compiler: aarch64-linux-gcc (GCC) 13.4.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250716/202507160405.SS3T4FhD-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/202507160405.SS3T4FhD-lkp@intel.com/ Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): In function '__cmpxchg_case_acq_4', inlined from '__cmpxchg_acq' at arch/arm64/include/asm/cmpxchg.h:141:1, inlined from 'queued_spin_lock' at include/asm-generic/qspinlock.h:85:8, inlined from 'do_raw_spin_lock' at include/linux/spinlock.h:180:2, inlined from '__raw_spin_lock' at include/linux/spinlock_api_smp.h:143:2, inlined from 'kvm_dying_cpu' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3447:2: arch/arm64/include/asm/atomic_lse.h:492:9: warning: array subscript 'long unsigned int[0]' is partly outside array bounds of 'raw_spinlock_t[1]' {aka 'struct raw_spinlock[1]'} [-Warray-bounds=] 492 | asm volatile( \ | ^~~ arch/arm64/include/asm/atomic_lse.h:515:1: note: in expansion of macro '__CMPXCHG_CASE' 515 | __CMPXCHG_CASE(w, , acq_4, a, "memory") | ^~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c: In function 'kvm_dying_cpu': arch/arm64/kvm/../../../virt/kvm/kvm_main.c:97:28: note: object 'kvm_count_lock' of size 4 97 | static DEFINE_RAW_SPINLOCK(kvm_count_lock); | ^~~~~~~~~~~~~~ include/linux/spinlock_types.h:59:48: note: in definition of macro 'DEFINE_RAW_SPINLOCK' 59 | #define DEFINE_RAW_SPINLOCK(x) raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x) | ^ In function '__cmpxchg_case_acq_4', inlined from '__cmpxchg_acq' at arch/arm64/include/asm/cmpxchg.h:141:1, inlined from 'queued_spin_lock' at include/asm-generic/qspinlock.h:85:8, inlined from 'do_raw_spin_lock' at include/linux/spinlock.h:180:2, inlined from '__raw_spin_lock' at include/linux/spinlock_api_smp.h:143:2, inlined from 'hardware_disable_all' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3465:2: arch/arm64/include/asm/atomic_lse.h:492:9: warning: array subscript 'long unsigned int[0]' is partly outside array bounds of 'raw_spinlock_t[1]' {aka 'struct raw_spinlock[1]'} [-Warray-bounds=] 492 | asm volatile( \ | ^~~ arch/arm64/include/asm/atomic_lse.h:515:1: note: in expansion of macro '__CMPXCHG_CASE' 515 | __CMPXCHG_CASE(w, , acq_4, a, "memory") | ^~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c: In function 'hardware_disable_all': arch/arm64/kvm/../../../virt/kvm/kvm_main.c:97:28: note: object 'kvm_count_lock' of size 4 97 | static DEFINE_RAW_SPINLOCK(kvm_count_lock); | ^~~~~~~~~~~~~~ include/linux/spinlock_types.h:59:48: note: in definition of macro 'DEFINE_RAW_SPINLOCK' 59 | #define DEFINE_RAW_SPINLOCK(x) raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x) | ^ In function '__cmpxchg_case_acq_4', inlined from '__cmpxchg_acq' at arch/arm64/include/asm/cmpxchg.h:141:1, inlined from 'queued_spin_lock' at include/asm-generic/qspinlock.h:85:8, inlined from 'do_raw_spin_lock' at include/linux/spinlock.h:180:2, inlined from '__raw_spin_lock' at include/linux/spinlock_api_smp.h:143:2, inlined from 'hardware_disable_all' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3465:2: arch/arm64/include/asm/atomic_lse.h:492:9: warning: array subscript 'long unsigned int[0]' is partly outside array bounds of 'raw_spinlock_t[1]' {aka 'struct raw_spinlock[1]'} [-Warray-bounds=] 492 | asm volatile( \ | ^~~ arch/arm64/include/asm/atomic_lse.h:515:1: note: in expansion of macro '__CMPXCHG_CASE' 515 | __CMPXCHG_CASE(w, , acq_4, a, "memory") | ^~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c: In function 'hardware_disable_all': arch/arm64/kvm/../../../virt/kvm/kvm_main.c:97:28: note: object 'kvm_count_lock' of size 4 97 | static DEFINE_RAW_SPINLOCK(kvm_count_lock); | ^~~~~~~~~~~~~~ include/linux/spinlock_types.h:59:48: note: in definition of macro 'DEFINE_RAW_SPINLOCK' 59 | #define DEFINE_RAW_SPINLOCK(x) raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x) | ^ In function '__cmpxchg_case_acq_4', inlined from '__cmpxchg_acq' at arch/arm64/include/asm/cmpxchg.h:141:1, inlined from 'queued_spin_lock' at include/asm-generic/qspinlock.h:85:8, inlined from 'do_raw_spin_lock' at include/linux/spinlock.h:180:2, inlined from '__raw_spin_lock' at include/linux/spinlock_api_smp.h:143:2, inlined from 'hardware_enable_all' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3474:2, inlined from 'kvm_create_vm' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:688:6: arch/arm64/include/asm/atomic_lse.h:492:9: warning: array subscript 'long unsigned int[0]' is partly outside array bounds of 'raw_spinlock_t[1]' {aka 'struct raw_spinlock[1]'} [-Warray-bounds=] 492 | asm volatile( \ | ^~~ arch/arm64/include/asm/atomic_lse.h:515:1: note: in expansion of macro '__CMPXCHG_CASE' 515 | __CMPXCHG_CASE(w, , acq_4, a, "memory") | ^~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c: In function 'kvm_create_vm': arch/arm64/kvm/../../../virt/kvm/kvm_main.c:97:28: note: object 'kvm_count_lock' of size 4 97 | static DEFINE_RAW_SPINLOCK(kvm_count_lock); | ^~~~~~~~~~~~~~ include/linux/spinlock_types.h:59:48: note: in definition of macro 'DEFINE_RAW_SPINLOCK' 59 | #define DEFINE_RAW_SPINLOCK(x) raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x) | ^ In function '__cmpxchg_case_acq_4', inlined from '__cmpxchg_acq' at arch/arm64/include/asm/cmpxchg.h:141:1, inlined from 'queued_spin_lock' at include/asm-generic/qspinlock.h:85:8, inlined from 'do_raw_spin_lock' at include/linux/spinlock.h:180:2, inlined from '__raw_spin_lock' at include/linux/spinlock_api_smp.h:143:2, inlined from 'hardware_enable_all' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3474:2, inlined from 'kvm_create_vm' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:688:6: arch/arm64/include/asm/atomic_lse.h:492:9: warning: array subscript 'long unsigned int[0]' is partly outside array bounds of 'raw_spinlock_t[1]' {aka 'struct raw_spinlock[1]'} [-Warray-bounds=] 492 | asm volatile( \ | ^~~ arch/arm64/include/asm/atomic_lse.h:515:1: note: in expansion of macro '__CMPXCHG_CASE' 515 | __CMPXCHG_CASE(w, , acq_4, a, "memory") | ^~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c: In function 'kvm_create_vm': arch/arm64/kvm/../../../virt/kvm/kvm_main.c:97:28: note: object 'kvm_count_lock' of size 4 97 | static DEFINE_RAW_SPINLOCK(kvm_count_lock); | ^~~~~~~~~~~~~~ include/linux/spinlock_types.h:59:48: note: in definition of macro 'DEFINE_RAW_SPINLOCK' 59 | #define DEFINE_RAW_SPINLOCK(x) raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x) | ^ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'kvm_vm_ioctl' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3097:7:

...

include/linux/uaccess.h:112:17: warning: 'cap' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'kvm_vm_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3094:39: note: 'cap' declared here 3094 | struct kvm_enable_cap cap; | ^~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'kvm_vm_ioctl' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3106:7: include/linux/uaccess.h:112:17: warning: 'kvm_userspace_mem' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'kvm_vm_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3103:52: note: 'kvm_userspace_mem' declared here 3103 | struct kvm_userspace_memory_region kvm_userspace_mem; | ^~~~~~~~~~~~~~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'kvm_vm_ioctl' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3117:7: include/linux/uaccess.h:112:17: warning: 'log' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'kvm_vm_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3114:38: note: 'log' declared here 3114 | struct kvm_dirty_log log; | ^~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'kvm_vm_ioctl' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3127:7: include/linux/uaccess.h:112:17: warning: 'zone' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'kvm_vm_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3124:48: note: 'zone' declared here 3124 | struct kvm_coalesced_mmio_zone zone; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'kvm_vm_ioctl' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3136:7: include/linux/uaccess.h:112:17: warning: 'zone' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'kvm_vm_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3133:48: note: 'zone' declared here 3133 | struct kvm_coalesced_mmio_zone zone; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'kvm_vm_ioctl' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3146:7: include/linux/uaccess.h:112:17: warning: 'data' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'kvm_vm_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3143:34: note: 'data' declared here 3143 | struct kvm_irqfd data; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'kvm_vm_ioctl' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3155:7: include/linux/uaccess.h:112:17: warning: 'data' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'kvm_vm_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3152:38: note: 'data' declared here 3152 | struct kvm_ioeventfd data; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'kvm_vm_ioctl' at arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3165:7: include/linux/uaccess.h:112:17: warning: 'msi' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'kvm_vm_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3162:32: note: 'msi' declared here 3162 | struct kvm_msi msi; | ^~~

vim +/cap +112 include/linux/uaccess.h d597580d373774 Al Viro 2017-03-20 104 d597580d373774 Al Viro 2017-03-20 105 #ifdef INLINE_COPY_FROM_USER d597580d373774 Al Viro 2017-03-20 106 static inline unsigned long d597580d373774 Al Viro 2017-03-20 107 _copy_from_user(void *to, const void __user *from, unsigned long n) d597580d373774 Al Viro 2017-03-20 108 { d597580d373774 Al Viro 2017-03-20 109 unsigned long res = n; 9c5f6908de03a4 Al Viro 2017-06-29 110 might_fault(); 4983cb67a383a7 Linus Torvalds 2019-02-14 111 if (likely(access_ok(from, n))) { 9c5f6908de03a4 Al Viro 2017-06-29 @112 kasan_check_write(to, n); d597580d373774 Al Viro 2017-03-20 113 res = raw_copy_from_user(to, from, n); 9c5f6908de03a4 Al Viro 2017-06-29 114 } d597580d373774 Al Viro 2017-03-20 115 if (unlikely(res)) d597580d373774 Al Viro 2017-03-20 116 memset(to + (n - res), 0, res); d597580d373774 Al Viro 2017-03-20 117 return res; d597580d373774 Al Viro 2017-03-20 118 } d597580d373774 Al Viro 2017-03-20 119 #else d597580d373774 Al Viro 2017-03-20 120 extern unsigned long d597580d373774 Al Viro 2017-03-20 121 _copy_from_user(void *, const void __user *, unsigned long); d597580d373774 Al Viro 2017-03-20 122 #endif d597580d373774 Al Viro 2017-03-20 123 :::::: The code at line 112 was first introduced by commit :::::: 9c5f6908de03a4f52ba7364b11fcd6116225480c copy_{from,to}_user(): move kasan checks and might_fault() out-of-line :::::: TO: Al Viro <viro@zeniv.linux.org.uk> :::::: CC: Al Viro <viro@zeniv.linux.org.uk> -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki