FYI, we noticed the following commit (built with gcc-7): commit: 558682b5291937a70748d36fd9ba757fb25b99ae ("x86/apic: Include the LDR when clearing out APIC registers") https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux.git master in testcase: locktorture with following parameters: runtime: 300s test: cpuhotplug test-description: This torture test consists of creating a number of kernel threads which acquire the lock and hold it for specific amount of time, thus simulating different critical region behaviors. test-url: https://www.kernel.org/doc/Documentation/locking/locktorture.txt on test machine: qemu-system-x86_64 -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 [ 7.133015] 2019-09-04 12:43:57 modprobe locktorture onoff_interval=3 onoff_holdoff=30 [ 7.133019] [ 7.183567] spin_lock-torture:--- Start of test: nwriters_stress=4 nreaders_stress=0 stat_interval=60 verbose=1 shuffle_interval=3 stutter=5 shutdown_secs=0 onoff_interval=3 onoff_holdoff=30 [ 7.192032] spin_lock-torture: Creating torture_onoff task [ 7.196178] spin_lock-torture: Creating torture_shuffle task [ 7.201958] spin_lock-torture: torture_onoff task started [ 7.206075] spin_lock-torture: Creating torture_stutter task [ 7.206696] spin_lock-torture: torture_onoff begin holdoff [ 7.209815] spin_lock-torture: torture_shuffle task started [ 7.216193] spin_lock-torture: Creating lock_torture_writer task [ 7.216234] spin_lock-torture: torture_stutter task started [ 7.228327] spin_lock-torture: Creating lock_torture_writer task [ 7.238474] spin_lock-torture: lock_torture_writer task started [ 7.243591] spin_lock-torture: Creating lock_torture_writer task [ 7.250485] spin_lock-torture: lock_torture_writer task started [ 7.252226] spin_lock-torture: lock_torture_writer task started [ 7.265344] spin_lock-torture: Creating lock_torture_writer task [ 7.272047] spin_lock-torture: Creating lock_torture_stats task [ 7.272184] spin_lock-torture: lock_torture_writer task started [ 7.280855] spin_lock-torture: lock_torture_stats task started [ 7.305768] 2019-09-04 12:43:57 sleep 300 [ 7.305775] [ 38.968157] spin_lock-torture: torture_onoff end holdoff [ 39.001403] Unregister pv shared memory for cpu 1 [ 39.008220] smpboot: CPU 1 is now offline [ 45.108980] x86: Booting SMP configuration: [ 45.117123] smpboot: Booting Node 0 Processor 1 APIC 0x1 [ 45.132201] kvm-clock: cpu 1, msr 2f4d041, secondary cpu clock [ 45.132258] masked ExtINT on CPU#1 [ 45.156638] KVM setup async PF for cpu 1 [ 45.160341] kvm-stealtime: cpu 1, msr 13fd16280 [ 48.217238] Unregister pv shared memory for cpu 1 [ 48.226796] smpboot: CPU 1 is now offline [ 67.636129] Writes: Total: 68085183 Max/Min: 0/0 Fail: 0 [ 69.960894] x86: Booting SMP configuration: [ 69.963177] smpboot: Booting Node 0 Processor 1 APIC 0x1 [ 69.973938] kvm-clock: cpu 1, msr 2f4d041, secondary cpu clock [ 69.973979] masked ExtINT on CPU#1 [ 69.999187] KVM setup async PF for cpu 1 [ 70.001297] kvm-stealtime: cpu 1, msr 13fd16280 [ 73.045264] Unregister pv shared memory for cpu 0 [ 73.056216] smpboot: CPU 0 is now offline [ 82.247373] smpboot: Booting Node 0 Processor 0 APIC 0x0 [ 92.248233] smpboot: do_boot_cpu failed(-1) to wakeup CPU#0 [ 92.251152] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 98.356295] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 104.500405] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 107.572446] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 110.644385] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 116.788294] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 119.860391] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 126.004433] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 129.076143] Writes: Total: 140150628 Max/Min: 0/0 Fail: 0 [ 135.220423] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 138.292323] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 150.603045] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 153.738026] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 166.196423] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 169.268356] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 181.628557] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 187.956291] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 190.516141] Writes: Total: 228688629 Max/Min: 0/0 Fail: 0 [ 206.479712] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 209.716312] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 218.932307] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 225.076331] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 228.148291] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 231.220355] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 237.364323] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 243.833755] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 247.092331] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 250.164344] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 251.956249] Writes: Total: 329509630 Max/Min: 0/0 Fail: 0 [ 253.236282] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 256.310783] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 259.380347] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 265.524352] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 268.620265] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 271.668326] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 274.740361] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 277.812290] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 280.884261] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 290.100277] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 293.172268] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 299.316355] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 302.465512] spin_lock-torture:torture_onoff task: online 0 failed: errno -5 [ 307.340664] 2019-09-04 12:48:58 rmmod locktorture [ 307.340667] [ 307.355820] spin_lock-torture: Stopping torture_shuffle task [ 307.358023] spin_lock-torture: Stopping torture_shuffle [ 307.359758] spin_lock-torture: Stopping torture_stutter task [ 307.363952] spin_lock-torture: Stopping torture_stutter [ 307.365776] spin_lock-torture: Stopping torture_onoff task [ 307.367733] spin_lock-torture: Stopping torture_onoff [ 307.371617] spin_lock-torture: Stopping lock_torture_writer task [ 307.373710] spin_lock-torture: Stopping lock_torture_writer [ 307.375647] spin_lock-torture: Stopping lock_torture_writer task [ 307.379987] spin_lock-torture: Stopping lock_torture_writer [ 307.381965] spin_lock-torture: Stopping lock_torture_writer [ 307.383816] spin_lock-torture: Stopping lock_torture_writer [ 307.387871] spin_lock-torture: Stopping lock_torture_writer task [ 307.389865] spin_lock-torture: Stopping lock_torture_writer task [ 307.391745] spin_lock-torture: Stopping lock_torture_stats task [ 307.395983] Writes: Total: 411175988 Max/Min: 0/0 Fail: 0 [ 307.397904] spin_lock-torture: Stopping lock_torture_stats [ 307.399675] Writes: Total: 411175988 Max/Min: 0/0 Fail: 0 [ 307.401624] spin_lock-torture:--- End of test: LOCK_HOTPLUG: nwriters_stress=4 nreaders_stress=0 stat_interval=60 verbose=1 shuffle_interval=3 stutter=5 shutdown_secs=0 onoff_interval=3 onoff_holdoff=30 To reproduce: # build kernel cd linux cp config-5.3.0-rc4-00015-g558682b529193 .config make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage modules make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 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 Thanks, Rong Chen