On Sat, Nov 25, 2023 at 10:06:39AM +0300, Dan Carpenter wrote: > Hi Shuai, > > kernel test robot noticed the following build warnings: > > https://git-scm.com/docs/git-format-patch#_base_tree_information] > > url: https://github.com/intel-lab-lkp/linux/commits/Shuai-Xue/docs-perf-Add-description-for-Synopsys-DesignWare-PCIe-PMU-driver/20231121-093713 > base: https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next > patch link: https://lore.kernel.org/r/20231121013400.18367-5-xueshuai%40linux.alibaba.com > patch subject: [PATCH v11 4/5] drivers/perf: add DesignWare PCIe PMU driver > config: x86_64-randconfig-r071-20231123 (https://download.01.org/0day-ci/archive/20231124/202311241906.0ymlLjyo-lkp@xxxxxxxxx/config) > compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07) > reproduce: (https://download.01.org/0day-ci/archive/20231124/202311241906.0ymlLjyo-lkp@xxxxxxxxx/reproduce) > > 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@xxxxxxxxx> > | Reported-by: Dan Carpenter <error27@xxxxxxxxx> > | Closes: https://lore.kernel.org/r/202311241906.0ymlLjyo-lkp@xxxxxxxxx/ > > smatch warnings: > drivers/perf/dwc_pcie_pmu.c:352 dwc_pcie_pmu_event_update() error: uninitialized symbol 'now'. > > vim +/now +352 drivers/perf/dwc_pcie_pmu.c > > 3481798a4ec51d1 Shuai Xue 2023-11-21 338 static void dwc_pcie_pmu_event_update(struct perf_event *event) > 3481798a4ec51d1 Shuai Xue 2023-11-21 339 { > 3481798a4ec51d1 Shuai Xue 2023-11-21 340 struct hw_perf_event *hwc = &event->hw; > 3481798a4ec51d1 Shuai Xue 2023-11-21 341 enum dwc_pcie_event_type type = DWC_PCIE_EVENT_TYPE(event); > 3481798a4ec51d1 Shuai Xue 2023-11-21 342 u64 delta, prev, now; > 3481798a4ec51d1 Shuai Xue 2023-11-21 343 > 3481798a4ec51d1 Shuai Xue 2023-11-21 344 do { > 3481798a4ec51d1 Shuai Xue 2023-11-21 345 prev = local64_read(&hwc->prev_count); > 3481798a4ec51d1 Shuai Xue 2023-11-21 346 > 3481798a4ec51d1 Shuai Xue 2023-11-21 347 if (type == DWC_PCIE_LANE_EVENT) > 3481798a4ec51d1 Shuai Xue 2023-11-21 348 now = dwc_pcie_pmu_read_lane_event_counter(event); > 3481798a4ec51d1 Shuai Xue 2023-11-21 349 else if (type == DWC_PCIE_TIME_BASE_EVENT) > 3481798a4ec51d1 Shuai Xue 2023-11-21 350 now = dwc_pcie_pmu_read_time_based_counter(event); > > uninitialized on else path. > > 3481798a4ec51d1 Shuai Xue 2023-11-21 351 > 3481798a4ec51d1 Shuai Xue 2023-11-21 @352 } while (local64_cmpxchg(&hwc->prev_count, prev, now) != prev); Shuai, any chance you can address this please? I think the event validation logic means that the type is only ever one of the cases you handle, so you probably just want to either initialise 'now' to 0 or WARN and return early if the type is unknown. Will
