Greeting, FYI, we noticed the following commit (built with gcc-9): commit: 2e8ed4544c1fe146637f194d7970530f3c33354e ("lib/vsprintf: Add support for printing V4L2 and DRM fourccs") git://linuxtv.org/sailus/media_tree.git fourcc in testcase: kernel-selftests version: kernel-selftests-x86_64-b5a583fb-1_20201015 with following parameters: group: kselftests-lib ucode: 0xdc test-description: The kernel contains a set of "self tests" under the tools/testing/selftests/ directory. These are intended to be small unit tests to exercise individual code paths in the kernel. test-url: https://www.kernel.org/doc/Documentation/kselftest.txt on test machine: 8 threads Intel(R) Core(TM) i7-6770HQ CPU @ 2.60GHz with 32G memory caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): If you fix the issue, kindly add following tag Reported-by: kernel test robot <rong.a.chen(a)intel.com&gt; KERNEL SELFTESTS: linux_headers_dir is /usr/src/linux-headers-x86_64-rhel-7.6-kselftests-2e8ed4544c1fe146637f194d7970530f3c33354e 2020-11-01 15:45:17 ln -sf /usr/bin/clang 2020-11-01 15:45:17 ln -sf /usr/bin/llc 2020-11-01 15:45:17 sed -i s/default_timeout=45/default_timeout=300/ kselftest/runner.sh 2020-11-01 15:45:17 make run_tests -C lib make: Entering directory '/usr/src/perf_selftests-x86_64-rhel-7.6-kselftests-2e8ed4544c1fe146637f194d7970530f3c33354e/tools/testing/selftests/lib' TAP version 13 1..4 # selftests: lib: printf.sh # printf: [FAIL] not ok 1 selftests: lib: printf.sh # exit=1 # selftests: lib: bitmap.sh # bitmap: ok ok 2 selftests: lib: bitmap.sh # selftests: lib: prime_numbers.sh # prime numbers: ok ok 3 selftests: lib: prime_numbers.sh # selftests: lib: strscpy.sh # strscpy*: ok ok 4 selftests: lib: strscpy.sh make: Leaving directory '/usr/src/perf_selftests-x86_64-rhel-7.6-kselftests-2e8ed4544c1fe146637f194d7970530f3c33354e/tools/testing/selftests/lib' To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp install job.yaml # job file is attached in this email bin/lkp run job.yaml Thanks, Rong Chen