FYI, we noticed the below changes on https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git testing.lookups commit 96352435afd792d713ec91e2d5693bdcf40a6b03 ("parallel lookups machinery, part 2") +-------------------------------------------------------+------------+------------+ | | 028d11dcb3 | 96352435af | +-------------------------------------------------------+------------+------------+ | boot_successes | 12 | 0 | | boot_failures | 0 | 12 | | kernel_BUG_at_mm/slab.c | 0 | 12 | | invalid_opcode:#[##]SMP | 0 | 12 | | RIP:kfree_debugcheck | 0 | 12 | | Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 0 | 12 | | backtrace:smpboot_thread_fn | 0 | 11 | +-------------------------------------------------------+------------+------------+ [ 56.931276] random: nonblocking pool is initialized [ 81.306979] kfree_debugcheck: out of range ptr a0h [ 81.308254] ------------[ cut here ]------------ [ 81.309323] kernel BUG at mm/slab.c:2599! [ 81.310557] invalid opcode: 0000 [#1] SMP [ 81.311669] Modules linked in: [ 81.312539] CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.6.0-rc1-00021-g9635243 #167 [ 81.314687] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 81.316678] task: ffff8800314b4080 ti: ffff8800314b8000 task.ti: ffff8800314b8000 [ 81.318633] RIP: 0010:[] [] kfree_debugcheck+0x25/0x2a [ 81.320659] RSP: 0000:ffff8800314bbcc8 EFLAGS: 00010092 [ 81.321788] RAX: 0000000000000026 RBX: 00000000000000a0 RCX: 0000000000000000 [ 81.323327] RDX: ffffffff8112e952 RSI: ffffffff82ea5638 RDI: ffffffff8111c147 [ 81.324783] RBP: ffff8800314bbcd0 R08: 0000000000000001 R09: 0000000000000000 [ 81.326214] R10: ffff8800314bbca8 R11: ffffffff831728b0 R12: 0000000000000206 [ 81.327586] R13: ffffffff811c97d1 R14: ffff88002abca1b8 R15: 0000000000000000 [ 81.329022] FS: 0000000000000000(0000) GS:ffff880033600000(0000) knlGS:0000000000000000 [ 81.331078] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 81.332283] CR2: 0000000047eb9da0 CR3: 000000002dba4000 CR4: 00000000000006f0 [ 81.333670] DR0: 00000000089cb000 DR1: 0000000000000000 DR2: 0000000000000000 [ 81.335118] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 [ 81.336572] Stack: [ 81.337315] 00000000000000a0 ffff8800314bbcf8 ffffffff812007a4 ffff88002a5c4380 [ 81.339449] ffffffff84081080 ffff88002a5c4380 ffff8800314bbd10 ffffffff811c97d1 [ 81.341560] ffff8800337d8d40 ffff8800314bbda0 ffffffff8113da92 ffff8800314bc000 [ 81.343828] Call Trace: [ 81.344757] [] kfree+0xdc/0x18c [ 81.346043] [] shmem_destroy_callback+0x19/0x2f [ 81.347545] [] rcu_process_callbacks+0x60d/0x830 [ 81.349030] [] ? shmem_destroy_inode+0x3b/0x3b [ 81.350491] [] __do_softirq+0x1a0/0x403 [ 81.351840] [] run_ksoftirqd+0x23/0x5c [ 81.353179] [] smpboot_thread_fn+0x1a9/0x1c0 [ 81.354574] [] ? cpumask_next+0x2f/0x2f [ 81.355885] [] kthread+0xc5/0xcd [ 81.357110] [] ? __wait_for_common+0x119/0x14c [ 81.358502] [] ret_from_fork+0x22/0x50 [ 81.359780] [] ? cpumask_check+0x35/0x35 [ 81.361114] Code: 41 5e 41 5f 5d c3 66 66 66 66 90 55 48 89 e5 53 48 89 fb e8 50 44 ea ff 84 c0 75 11 48 89 de 48 c7 c7 04 4c 9e 83 e8 bb 3b fb ff <0f> 0b 5b 5d c3 8b 4f 18 48 29 f2 55 89 d6 48 89 e5 5d 48 0f af [ 81.366666] RIP [] kfree_debugcheck+0x25/0x2a [ 81.367604] RSP [ 81.368286] ---[ end trace 1f4ba232faf192ba ]--- [ 81.369021] Kernel panic - not syncing: Fatal exception in interrupt vm-kbuild-yocto-ia32: 1 threads qemu-system-x86_64 -enable-kvm -cpu Westmere with 320M memory FYI, raw QEMU command line is: qemu-system-x86_64 -enable-kvm -cpu Westmere -kernel /pkg/linux/x86_64-allyesdebian/gcc-5/96352435afd792d713ec91e2d5693bdcf40a6b03/vmlinuz-4.6.0-rc1-00021-g9635243 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-kbuild-yocto-ia32-8/rand_boot-1-yocto-minimal-i386.cgz-x86_64-allyesdebian-96352435afd792d713ec91e2d5693bdcf40a6b03-20160416-73769-rktar3-0.yaml ARCH=x86_64 kconfig=x86_64-allyesdebian branch=vfs/testing.lookups commit=96352435afd792d713ec91e2d5693bdcf40a6b03 BOOT_IMAGE=/pkg/linux/x86_64-allyesdebian/gcc-5/96352435afd792d713ec91e2d5693bdcf40a6b03/vmlinuz-4.6.0-rc1-00021-g9635243 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-kbuild-yocto-ia32/yocto-minimal-i386.cgz/x86_64-allyesdebian/gcc-5/96352435afd792d713ec91e2d5693bdcf40a6b03/0 LKP_SERVER=inn earlyprintk=ttyS0,115200 systemd.log_level=err debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal rw ip=::::vm-kbuild-yocto-ia32-8::dhcp drbd.minor_count=8' -initrd /fs/sdh1/initrd-vm-kbuild-yocto-ia32-8 -m 832 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sdh1/disk0-vm-kbuild-yocto-ia32-8,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-kbuild-yocto-ia32-8 -serial file:/dev/shm/kboot/serial-vm-kbuild-yocto-ia32-8 -daemonize -display none -monitor null Thanks, Kernel Test Robot