FYI, we noticed the following commit (built with gcc-7): commit: b33ddf50ebcc740b990dd2e0e8ff0b92c7acf58e ("mm: Protect mm_rb tree with a rwlock") url: https://github.com/0day-ci/linux/commits/Laurent-Dufour/Speculative-page-faults/20180316-151833 in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 4G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +----------------------------------------+------------+------------+ | | 7f3f7b4e80 | b33ddf50eb | +----------------------------------------+------------+------------+ | boot_successes | 8 | 0 | | boot_failures | 0 | 6 | | INFO:trying_to_register_non-static_key | 0 | 6 | +----------------------------------------+------------+------------+ [ 22.218186] INFO: trying to register non-static key. [ 22.220252] the code is fine but needs lockdep annotation. [ 22.222471] turning off the locking correctness validator. [ 22.224839] CPU: 0 PID: 1 Comm: init Not tainted 4.16.0-rc4-next-20180309-00017-gb33ddf5 #1 [ 22.228528] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 22.232443] Call Trace: [ 22.234234] dump_stack+0x85/0xbc [ 22.236085] register_lock_class+0x237/0x477 [ 22.238057] __lock_acquire+0xd0/0xf15 [ 22.240032] lock_acquire+0x19c/0x1ce [ 22.241927] ? do_mmap+0x3aa/0x3ff [ 22.243749] mmap_region+0x37a/0x4c0 [ 22.245619] ? do_mmap+0x3aa/0x3ff [ 22.247425] do_mmap+0x3aa/0x3ff [ 22.249175] vm_mmap_pgoff+0xa1/0xea [ 22.251083] elf_map+0x6d/0x134 [ 22.252873] load_elf_binary+0x56f/0xe07 [ 22.254853] search_binary_handler+0x75/0x1f8 [ 22.256934] do_execveat_common+0x661/0x92b [ 22.259164] ? rest_init+0x22e/0x22e [ 22.261082] do_execve+0x1f/0x21 [ 22.262884] kernel_init+0x5a/0xf0 [ 22.264722] ret_from_fork+0x3a/0x50 [ 22.303240] systemd[1]: RTC configured in localtime, applying delta of 480 minutes to system time. [ 22.313544] systemd[1]: Failed to insert module 'autofs4': No such file or directory [ 22.513663] input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input3 Mounting Debug File System... Starting Create list of required st... nodes for the current kernel... Starting Remount Root and Kernel File Systems... Mounting Huge Pages File System... Starting Journal Service... Starting Load Kernel Modules... Mounting POSIX Message Queue File System... Mounting RPC Pipe File System... Mounting Configuration File System... Starting Apply Kernel Variables... Mounting FUSE Control File System... Starting Flush Journal to Persistent Storage... Starting Load/Save Random Seed... Starting udev Coldplug all Devices... Starting Create Static Device Nodes in /dev... Starting udev Kernel Device Manager... Starting Preprocess NFS configuration... Starting Create Volatile Files and Directories... Starting Network Time Synchronization... Starting RPC bind portmap service... Starting Update UTMP about System Boot/Shutdown... [ 24.727672] input: PC Speaker as /devices/platform/pcspkr/input/input4 Starting OpenBSD Secure Shell server... Starting /etc/rc.local Compatibility... Starting Permit User Sessions... Starting LKP bootstrap... [ 24.923463] rc.local[3526]: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/lkp/lkp/src/bin Starting Login Service... LKP: HOSTNAME vm-lkp-nex04-4G-18, MAC 52:54:00:12:34:56, kernel 4.16.0-rc4-next-20180309-00017-gb33ddf5 1, serial console /dev/ttyS0 [ 25.479682] Kernel tests: Boot OK! [ 25.479710] [ 25.644452] install debs round one: dpkg -i --force-confdef --force-depends /opt/deb/gawk_1%3a4.1.4+dfsg-1_amd64.deb [ 25.644475] [ 25.668363] /opt/deb/sysstat_11.6.0-1_amd64.deb [ 25.668384] [ 25.722852] (Reading database ... 2202 files and directories currently installed.) [ 25.722894] [ 25.744726] Preparing to unpack .../gawk_1%3a4.1.4+dfsg-1_amd64.deb ... [ 25.744756] [ 25.783727] Unpacking gawk (1:4.1.4+dfsg-1) over (1:4.1.1+dfsg-1) ... [ 25.783756] [ 26.409737] Selecting previously unselected package sysstat. [ 26.409765] [ 26.447612] Preparing to unpack .../deb/sysstat_11.6.0-1_amd64.deb ... [ 26.447643] [ 26.489959] Unpacking sysstat (11.6.0-1) ... [ 26.489988] [ 26.995116] Setting up gawk (1:4.1.4+dfsg-1) ... [ 26.995146] [ 27.102542] Setting up sysstat (11.6.0-1) ... [ 27.102573] [ 30.773854] Processing triggers for systemd (231-5) ... [ 30.773873] [ 30.851184] /lkp/lkp/src/bin/run-lkp [ 30.851205] [ 30.917864] RESULT_ROOT=/result/boot/1/vm-lkp-nex04-4G/debian-x86_64-2016-08-31.cgz/x86_64-nfsroot/gcc-7/b33ddf50ebcc740b990dd2e0e8ff0b92c7acf58e/0 [ 30.917885] [ 30.949653] job=/lkp/scheduled/vm-lkp-nex04-4G-18/boot-1-debian-x86_64-2016-08-31.cgz-b33ddf50ebcc740b990dd2e0e8ff0b92c7acf58e-20180316-52130-1wxdvik-0.yaml [ 30.949673] [ 30.958745] mount.nfs: try 1 time... [ 30.958760] [ 31.190880] mount.nfs (3761) used greatest stack depth: 12424 bytes left [ 31.264066] run-job /lkp/scheduled/vm-lkp-nex04-4G-18/boot-1-debian-x86_64-2016-08-31.cgz-b33ddf50ebcc740b990dd2e0e8ff0b92c7acf58e-20180316-52130-1wxdvik-0.yaml [ 31.264087] [ 31.338975] /usr/bin/curl -sSf http://inn:80/~lkp/cgi-bin/lkp-jobfile-append-var?job_file=/lkp/scheduled/vm-lkp-nex04-4G-18/boot-1-debian-x86_64-2016-08-31.cgz-b33ddf50ebcc740b990dd2e0e8ff0b92c7acf58e-20180316-52130-1wxdvik-0.yaml&job_state=running -o /dev/null [ 31.339035] [ 34.814078] skip microcode check for virtual machine [ 34.814099] [ 35.520694] random: crng init done [ 38.000898] /usr/bin/curl -sSf http://inn:80/~lkp/cgi-bin/lkp-jobfile-append-var?job_file=/lkp/scheduled/vm-lkp-nex04-4G-18/boot-1-debian-x86_64-2016-08-31.cgz-b33ddf50ebcc740b990dd2e0e8ff0b92c7acf58e-20180316-52130-1wxdvik-0.yaml&job_state=post_run -o /dev/null [ 38.000920] [ 40.029932] kill 3803 dmesg --follow --decode [ 40.029959] To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, lkp