FYI, we noticed the following commit: commit: 935356cecda851d94381e1c6fea9dec443f908fe ("x86/apic: Initialize interrupt mode after timer init") https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git x86/apic in testcase: will-it-scale with following parameters: nr_task: 100% mode: process test: open2 cpufreq_governor: performance test-description: Will It Scale takes a testcase and runs it from 1 through to n parallel copies to see if the testcase will scale. It builds both a process and threads based test in order to see any differences between the two. test-url: https://github.com/antonblanchard/will-it-scale on test machine: 256 threads Phi with 96G memory caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +----------------+------------+------------+ | | 34fba3e6b1 | 935356cecd | +----------------+------------+------------+ | boot_successes | 4 | 4 | +----------------+------------+------------+ kern :info : [ 0.020000] tsc: Fast TSC calibration using PIT kern :info : [ 0.024000] tsc: Detected 1297.000 MHz processor kern :info : [ 0.028000] Calibrating delay loop (skipped), value calculated using timer frequency.. 2594.00 BogoMIPS (lpj=5188000) kern :info : [ 0.032007] pid_max: default: 278528 minimum: 2176 kern :info : [ 0.036266] ACPI: Core revision 20170728 kern :err : [ 0.040010] ACPI Error: Table [DMAR] is not invalidated during early boot stage (20170728/tbxface-196) kern :info : [ 0.105384] ACPI: 3 ACPI AML tables successfully acquired and loaded kern :info : [ 0.132721] Dentry cache hash table entries: 8388608 (order: 14, 67108864 bytes) kern :info : [ 0.149441] Inode-cache hash table entries: 4194304 (order: 13, 33554432 bytes) kern :info : [ 0.152556] Mount-cache hash table entries: 131072 (order: 8, 1048576 bytes) kern :info : [ 0.156404] Mountpoint-cache hash table entries: 131072 (order: 8, 1048576 bytes) 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, lkp