On Wed, Oct 26, 2022 at 01:43:48AM +0530, Naresh Kamboju wrote:
Following build warning / errors noticed while building x86_64 with clang on Linux next-20221025 tag.
Reported-by: Linux Kernel Functional Testing lkft@linaro.org
## Build
- kernel: 6.1.0-rc2
- git: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next
- git branch: master
- git commit: 89bf6e28373beef9577fa71f996a5f73a569617c
- git describe: next-20221025
- test details:
https://qa-reports.linaro.org/lkft/linux-next-master-sanity/build/next-20221...
## Test Regressions (compared to next-20221024) Regressions found on x86_64:
- clang-nightly-lkftconfig
- clang-12-lkftconfig
- clang-14-lkftconfig
- clang-13-lkftconfig
- clang-14-lkftconfig-kcsan
make --silent --keep-going --jobs=8 O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM=1 LLVM_IAS=1 ARCH=x86_64 CROSS_COMPILE=x86_64-linux-gnu- 'HOSTCC=sccache clang' 'CC=sccache clang' mm/khugepaged.c:1729:7: error: variable 'index' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (!xas_nomem(&xas, GFP_KERNEL)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/khugepaged.c:2063:47: note: uninitialized use occurs here trace_mm_khugepaged_collapse_file(mm, hpage, index, is_shmem, ^~~~~ mm/khugepaged.c:1729:3: note: remove the 'if' if its condition is always false if (!xas_nomem(&xas, GFP_KERNEL)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/khugepaged.c:1716:6: error: variable 'index' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (result != SCAN_SUCCEED) ^~~~~~~~~~~~~~~~~~~~~~ mm/khugepaged.c:2063:47: note: uninitialized use occurs here trace_mm_khugepaged_collapse_file(mm, hpage, index, is_shmem, ^~~~~ mm/khugepaged.c:1716:2: note: remove the 'if' if its condition is always false if (result != SCAN_SUCCEED) ^~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/khugepaged.c:1705:15: note: initialize the variable 'index' to silence this warning pgoff_t index, end = start + HPAGE_PMD_NR; ^ = 0 mm/khugepaged.c:1729:7: error: variable 'nr' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (!xas_nomem(&xas, GFP_KERNEL)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/khugepaged.c:2064:15: note: uninitialized use occurs here addr, file, nr, result); ^~ mm/khugepaged.c:1729:3: note: remove the 'if' if its condition is always false if (!xas_nomem(&xas, GFP_KERNEL)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/khugepaged.c:1716:6: error: variable 'nr' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (result != SCAN_SUCCEED) ^~~~~~~~~~~~~~~~~~~~~~ mm/khugepaged.c:2064:15: note: uninitialized use occurs here addr, file, nr, result); ^~ mm/khugepaged.c:1716:2: note: remove the 'if' if its condition is always false if (result != SCAN_SUCCEED) ^~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/khugepaged.c:1710:8: note: initialize the variable 'nr' to silence this warning int nr; ^ = 0 4 errors generated. make[3]: *** [scripts/Makefile.build:250: mm/khugepaged.o] Error 1
I sent https://lore.kernel.org/20221025173407.3423241-1-nathan@kernel.org/ for this earlier today.
Cheers, Nathan