Greeting, FYI, we noticed the following commit (built with clang-15): commit: 5bffe4c611f567d83c579378c54b13c21fd0fb98 ("PCI/PM: Rework changing power states of PCI devices") https://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git pci/pm in testcase: boot on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G 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 please be noted, since we didn't find direct clue to the issue caused by this commit, while making sure the config is same for it and parent, we rerun more times. we observed there is a 25% rate on this commit, but keeps clean on parent. e8a37022c16ae719 5bffe4c611f567d83c579378c54 ---------------- --------------------------- fail:runs %reproduction fail:runs | | | :100 25% 25:100 dmesg.BUG:kernel_reboot-without-warning_in_test_stage then we noticed that the 'bad' run on this commit generally stop abruptly like below (detail dmesg attached as dmesg.xz): [ 43.150719][ T41] rcu-scale: 1 writer-duration: 51 14438086 [ 43.150723][ T41] rcu-scale: 1 writer-duration: 52 13912616 [ 43.150728][ T41] rcu-scale: 1 writer-duration: 53 8321817 [ 43.150732][ T41] rcu-scale: 1 writer-duration: 54 13430914 [ 43.150737][ T41] rcu-scale: 1 writer-duration: 55 5860957 BUG: kernel reboot-without-warning in test stage and for those 'good' runs on this commit, generally end up like: (detail dmesg attached as dmesg-good.xz) [ 26.204793][ T41] rcu-scale: 1 writer-duration: 99 10163595 [ 26.205348][ T41] rcu-scale: 1 writer-duration: 100 20268875 [ 26.228712][ T41] rcu-scale: 1 writer-duration: 101 18695075 [ 26.229309][ T41] rcu-scale: 1 writer-duration: 102 13985570 [ 26.229873][ T41] rcu-scale: 1 writer-duration: 103 6422709 [ 26.242702][ T41] ACPI: PM: Preparing to enter system sleep state S5 [ 26.248010][ T41] reboot: Power down and for parent, generally ends up like: (detail dmesg attached as dmesg-parent.xz) [ 31.312023][ T41] rcu-scale: 1 writer-duration: 99 13060706 [ 31.312952][ T41] rcu-scale: 1 writer-duration: 100 9798062 [ 31.363511][ T41] rcu-scale: 1 writer-duration: 101 12240715 [ 31.364526][ T41] rcu-scale: 1 writer-duration: 102 16554300 [ 31.365456][ T41] rcu-scale: 1 writer-duration: 103 18276029 [ 32.468788][ T340] _warn_unseeded_randomness: 32 callbacks suppressed [ 32.468795][ T340] random: get_random_u32 called from arch_pick_mmap_layout+0x7b/0x190 with crng_init=1 [ 32.469575][ T340] random: get_random_u32 called from randomize_stack_top+0x27/0x50 with crng_init=1 [ 32.469582][ T340] random: get_random_u32 called from arch_align_stack+0x29/0x40 with crng_init=1 [ 33.164431][ T41] ACPI: PM: Preparing to enter system sleep state S5 [ 33.173518][ T41] reboot: Power down To reproduce: # build kernel cd linux cp config-5.18.0-rc1-00005-g5bffe4c611f5 .config make HOSTCC=clang-15 CC=clang-15 ARCH=i386 olddefconfig prepare modules_prepare bzImage modules make HOSTCC=clang-15 CC=clang-15 ARCH=i386 INSTALL_MOD_PATH= modules_install cd find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k -m modules.cgz job-script # job-script is attached in this email # if come across any failure that blocks the test, # please remove ~/.lkp and /lkp dir to run from a clean state. -- 0-DAY CI Kernel Test Service https://01.org/lkp