FYI, we noticed the following commit:

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
commit a6efa0b2aa5568872abff95bfa7d8a4dba00f86f ("mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB")

in testcase: boot

on test machine: 1 threads qemu-system-x86_64 -enable-kvm -cpu SandyBridge with 320M memory

caused below changes:


 7809 [   18.666107] UBSAN: Undefined behaviour in mm/kasan/quarantine.c:102:13
 7810 [   18.668198] member access within misaligned address ffff88000d1efebc for type 'struct qlist_node'
 7811 [   18.670368] which requires 8 byte alignment
 7812 [   18.671494] CPU: 0 PID: 1 Comm: swapper Not tainted 4.7.0-rc7-00368-ga6efa0b #1
 7813 [   18.673400] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
 7814 [   18.675812]  0000000000000000 ffff88000d4af918 ffffffff81ac3c82 ffff88000d4af938
 7815 [   18.678219]  ffffffff81b60046 000000000000001f ffffffff8370a6c0 ffff88000d4af9d8
 7816 [   18.680606]  ffffffff81b60a2f ffffffff8370b44c 0000000041b58ab3 ffffffff82b6a7c6
 7817 [   18.683014] Call Trace:
 7818 [   18.683822]  [<ffffffff81ac3c82>] dump_stack+0x19/0x1b
 7819 [   18.685112]  [<ffffffff81b60046>] ubsan_epilogue+0xe/0x84
 7820 [   18.687650]  [<ffffffff81b60a2f>] __ubsan_handle_type_mismatch+0x1e2/0x20a
 7821 [   18.689369]  [<ffffffff81b6084d>] ? __ubsan_handle_divrem_overflow+0x16c/0x16c
 7822 [   18.691296]  [<ffffffff81339dd2>] ? ___slab_alloc+0x710/0x93e
 7823 [   18.692941]  [<ffffffff81ac781f>] ? idr_get_empty_slot+0xddf/0xddf
 7824 [   18.698603]  [<ffffffff81343846>] quarantine_reduce+0x1d3/0x23f
 7825 [   18.700062]  [<ffffffff81341ef4>] kasan_kmalloc+0x28/0x91
 7826 [   18.701428]  [<ffffffff81341f6f>] kasan_slab_alloc+0x12/0x14                                                                                                                                                                                                               
 7827 [   18.702846]  [<ffffffff8133a3c4>] kmem_cache_alloc+0x334/0x451
 7828 [   18.704305]  [<ffffffff81478c73>] ? __kernfs_new_node+0xa9/0x1ff
 7829 [   18.705794]  [<ffffffff81478c73>] __kernfs_new_node+0xa9/0x1ff
 7830 [   18.707243]  [<ffffffff81478bca>] ? kernfs_dop_revalidate+0x2c9/0x2c9
 7831 [   18.721888]  [<ffffffff81ad541c>] ? rb_first+0x35/0x8c
 7832 [   18.723213]  [<ffffffff81478843>] ? kernfs_leftmost_descendant+0x48/0x5b
 7833 [   18.724800]  [<ffffffff8147c0a7>] kernfs_new_node+0xa0/0xe2
 7834 [   18.726201]  [<ffffffff81480506>] __kernfs_create_file+0x33/0x19f
 7835 [   18.727704]  [<ffffffff81482179>] sysfs_add_file_mode_ns+0x26c/0x3cd
 7836 [   18.729371]  [<ffffffff81482505>] sysfs_add_file+0x50/0x57
 7837 [   18.730834]  [<ffffffff81483ff0>] sysfs_merge_group+0x109/0x1d4
 7838 [   18.748017]  [<ffffffff81dd60bc>] dpm_sysfs_add+0x9e/0x13e
 7839 [   18.749196]  [<ffffffff81dbb549>] device_add+0xa66/0x1034
 7840 [   18.750342]  [<ffffffff81dbaae3>] ? device_private_init+0x1e9/0x1e9
 7841 [   18.751629]  [<ffffffff81db7eac>] ? device_create_file+0x155/0x155
 7842 [   18.752898]  [<ffffffff8133a926>] ? kmem_cache_alloc_trace+0x445/0x457
 7843 [   18.754233]  [<ffffffff81dc09d3>] ? subsys_register+0x3d/0x168
 7844 [   18.755544]  [<ffffffff81dbbb31>] device_register+0x1a/0x1d
 7845 [   18.756717]  [<ffffffff81dc0a97>] subsys_register+0x101/0x168
 7846 [   18.758022]  [<ffffffff81dc3561>] subsys_system_register+0x34/0x3a
 7847 [   18.759308]  [<ffffffff86c85359>] ? edac_mc_sysfs_init+0xcf/0xcf
 7848 [   18.769681]  [<ffffffff86c85378>] edac_init+0x1f/0x70
 7849 [   18.779343]  [<ffffffff81000597>] do_one_initcall+0x14e/0x200
 7850 [   18.780772]  [<ffffffff81000449>] ? initcall_blacklisted+0x146/0x146
 7851 [   18.790449]  [<ffffffff8114c800>] ? remove_wait_queue+0x154/0x1ca
 7852 [   18.791916]  [<ffffffff8112f59a>] ? preempt_count_sub+0x18/0xd9
 7853 [   18.793370]  [<ffffffff86c01a28>] kernel_init_freeable+0x2b8/0x34c
 7854 [   18.794868]  [<ffffffff82580aba>] kernel_init+0x11/0x11b
 7855 [   18.796185]  [<ffffffff8258becf>] ret_from_fork+0x1f/0x40
 7856 [   18.797540]  [<ffffffff82580aa9>] ? rest_init+0x90/0x90
 7857 [   18.807610] ================================================================================



FYI, raw QEMU command line is:

	qemu-system-x86_64 -enable-kvm -cpu SandyBridge -kernel /pkg/linux/x86_64-randconfig-s4-07242348/gcc-6/a6efa0b2aa5568872abff95bfa7d8a4dba00f86f/vmlinuz-4.7.0-rc7-00368-ga6efa0b -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-kbuild-yocto-x86_64-59/boot-1-yocto-minimal-x86_64.cgz-a6efa0b2aa5568872abff95bfa7d8a4dba00f86f-20160725-6441-1w86cht-0.yaml ARCH=x86_64 kconfig=x86_64-randconfig-s4-07242348 branch=linux-next/master commit=a6efa0b2aa5568872abff95bfa7d8a4dba00f86f BOOT_IMAGE=/pkg/linux/x86_64-randconfig-s4-07242348/gcc-6/a6efa0b2aa5568872abff95bfa7d8a4dba00f86f/vmlinuz-4.7.0-rc7-00368-ga6efa0b max_uptime=600 RESULT_ROOT=/result/boot/1/vm-kbuild-yocto-x86_64/yocto-minimal-x86_64.cgz/x86_64-randconfig-s4-07242348/gcc-6/a6efa0b2aa5568872abff95bfa7d8a4dba00f86f/0 LKP_SERVER=inn 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 systemd.log_level=err ignore_loglevel earlyprintk=ttyS0,115200 console=ttyS0,115200 console=tty0 vga=normal rw ip=::::vm-kbuild-yocto-x86_64-59::dhcp drbd.minor_count=8'  -initrd /fs/sdg1/initrd-vm-kbuild-yocto-x86_64-59 -m 320 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sdg1/disk0-vm-kbuild-yocto-x86_64-59,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-kbuild-yocto-x86_64-59 -serial file:/dev/shm/kboot/serial-vm-kbuild-yocto-x86_64-59 -daemonize -display none -monitor null 





Thanks,
Xiaolong