* [arm-platforms:kvm-arm64/pmu-chained 6/6] arch/arm64/kvm/pmu-emul.c:175:7: warning: variable 'val' is used uninitialized whenever 'if' condition is false
@ 2022-08-01 23:01 kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2022-08-01 23:01 UTC (permalink / raw)
To: Marc Zyngier; +Cc: llvm, kbuild-all, linux-arm-kernel
tree: https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/pmu-chained
head: ed5c6c9ddd3a3376659e45652c263cee7ee0ac2f
commit: ed5c6c9ddd3a3376659e45652c263cee7ee0ac2f [6/6] rework overflow conditions
config: arm64-buildonly-randconfig-r003-20220801 (https://download.01.org/0day-ci/archive/20220802/202208020643.wTCgOkeH-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 52cd00cabf479aa7eb6dbb063b7ba41ea57bce9e)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm64 cross compiling tool for clang build
# apt-get install binutils-aarch64-linux-gnu
# https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?id=ed5c6c9ddd3a3376659e45652c263cee7ee0ac2f
git remote add arm-platforms https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git
git fetch --no-tags arm-platforms kvm-arm64/pmu-chained
git checkout ed5c6c9ddd3a3376659e45652c263cee7ee0ac2f
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash arch/arm64/kvm/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> arch/arm64/kvm/pmu-emul.c:175:7: warning: variable 'val' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (!kvm_pmu_idx_is_64bit(vcpu, pmc->idx))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/arm64/kvm/pmu-emul.c:179:30: note: uninitialized use occurs here
__vcpu_sys_reg(vcpu, reg) = val;
^~~
arch/arm64/kvm/pmu-emul.c:175:3: note: remove the 'if' if its condition is always true
if (!kvm_pmu_idx_is_64bit(vcpu, pmc->idx))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/arm64/kvm/pmu-emul.c:163:23: note: initialize the variable 'val' to silence this warning
u64 counter, reg, val;
^
= 0
1 warning generated.
vim +175 arch/arm64/kvm/pmu-emul.c
154
155 /**
156 * kvm_pmu_stop_counter - stop PMU counter
157 * @pmc: The PMU counter pointer
158 *
159 * If this counter has been configured to monitor some event, release it here.
160 */
161 static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
162 {
163 u64 counter, reg, val;
164
165 if (!pmc->perf_event)
166 return;
167
168 counter = kvm_pmu_get_counter_value(vcpu, pmc->idx);
169
170 if (pmc->idx == ARMV8_PMU_CYCLE_IDX) {
171 reg = PMCCNTR_EL0;
172 val = counter;
173 } else {
174 reg = PMEVCNTR0_EL0 + pmc->idx;
> 175 if (!kvm_pmu_idx_is_64bit(vcpu, pmc->idx))
176 val = lower_32_bits(counter);
177 }
178
179 __vcpu_sys_reg(vcpu, reg) = val;
180
181 kvm_pmu_release_perf_event(pmc);
182 }
183
--
0-DAY CI Kernel Test Service
https://01.org/lkp
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