FYI, we noticed the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git x86/uaccess commit 6f2d5395a55901d674b41a9ebe2a03ae28050739 ("x86/uaccess: OOPS or warn on a fault with KERNEL_DS and !pagefault_disabled()") on test machine: vm-vp-quantal-i386: 1 threads qemu-system-i386 -enable-kvm -cpu Haswell,+smep,+smap with 360M memory caused below changes: +----------------+------------+------------+ | | 1e260fb1ca | 6f2d5395a5 | +----------------+------------+------------+ | boot_successes | 4 | 0 | +----------------+------------+------------+ [ 0.135028] apic 0 pin 23 not connected [ 0.135488] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 [ 0.135989] TSC deadline timer enabled [ 0.136509] BUG: uaccess fault at 0xd3634000 with KERNEL_DS [ 0.136956] BUG: unable to handle kernel paging request at d3634000 [ 0.137471] IP: [<c1102ff3>] copy_mount_options+0x86/0xd8 [ 0.137915] *pdpt = 00000000018a9001 *pde = 0000000014776067 *pte = 8000000013634060 [ 0.138557] Oops: 0000 [#1] DEBUG_PAGEALLOC [ 0.138883] Modules linked in: [ 0.139146] CPU: 0 PID: 8 Comm: kdevtmpfs Not tainted 4.7.0-rc1-00030-g6f2d539 #1 [ 0.139728] task: d35eba40 ti: d3632000 task.ti: d3632000 [ 0.140186] task.addr_limit: 0xffffffff [ 0.140512] EIP: 0060:[<c1102ff3>] EFLAGS: 00210202 CPU: 0 [ 0.140954] EIP is at copy_mount_options+0x86/0xd8 [ 0.141350] EAX: d3634000 EBX: d35c6458 ECX: 00000000 EDX: ffffff00 [ 0.141862] ESI: d35c656e EDI: 00000000 EBP: d3633e88 ESP: d3633e74 [ 0.142420] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 [ 0.142881] CR0: 80050033 CR2: d3634000 CR3: 018ac000 CR4: 000406b0 [ 0.143391] Stack: [ 0.143557] 00000eea 00001000 d361baf8 d361baf8 d3633ef4 d3633ea0 c1103c29 d361b3f0 [ 0.144246] d35f1f7c c16f18d3 d3633ef4 d3633f34 c12eeaf6 c16f1939 c16bb4f5 c16f1939 [ 0.144967] 00008000 d3633eea c104e888 00000001 00000001 c179cb60 d35eba40 c179cb60 [ 0.145676] Call Trace: [ 0.145886] [<c1103c29>] SyS_mount+0x36/0x76 [ 0.146253] [<c12eeaf6>] devtmpfsd+0x4c/0x28e [ 0.146603] [<c104e888>] ? finish_task_switch+0x109/0x162 [ 0.147037] [<c148aa62>] ? _raw_spin_unlock_irq+0x1d/0x2c [ 0.147476] [<c104e888>] ? finish_task_switch+0x109/0x162 [ 0.147907] [<c104e85b>] ? finish_task_switch+0xdc/0x162 [ 0.148335] [<c14877ba>] ? __schedule+0x328/0x456 [ 0.148714] [<c12eeaaa>] ? handle_remove+0x233/0x233 [ 0.149112] [<c12eeaaa>] ? handle_remove+0x233/0x233 [ 0.149509] [<c1049a60>] kthread+0xa8/0xad [ 0.149839] [<c148af22>] ret_from_kernel_thread+0xe/0x24 [ 0.150320] [<c10499b8>] ? kthread_create_on_node+0x11c/0x11c [ 0.150774] Code: 12 39 c2 72 0e 8b 7d f0 89 f0 89 de 89 7d ec 31 ff eb 0d 8b 55 f0 eb 28 ff 4d ec 46 88 56 ff 40 83 7d ec 00 74 17 8d 76 00 89 f9 <8a> 10 8d 76 00 85 c9 74 e4 8b 4d ec 31 c0 89 f7 f3 aa 8b 55 ec [ 0.152937] EIP: [<c1102ff3>] copy_mount_options+0x86/0xd8 SS:ESP 0068:d3633e74 [ 0.153532] CR2: 00000000d3634000 [ 0.153799] ---[ end trace 4fb99d4ea4386d1c ]--- [ 0.154199] Kernel panic - not syncing: Fatal exception FYI, raw QEMU command line is: qemu-system-i386 -enable-kvm -cpu Haswell,+smep,+smap -kernel /pkg/linux/i386-randconfig-h1-06010516/gcc-6/6f2d5395a55901d674b41a9ebe2a03ae28050739/vmlinuz-4.7.0-rc1-00030-g6f2d539 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-vp-quantal-i386-27/bisect_boot-1-quantal-core-i386.cgz-i386-randconfig-h1-06010516-6f2d5395a55901d674b41a9ebe2a03ae28050739-20160601-86867-1u5hj7g-0.yaml ARCH=i386 kconfig=i386-randconfig-h1-06010516 branch=linux-devel/devel-hourly-2016060102 commit=6f2d5395a55901d674b41a9ebe2a03ae28050739 BOOT_IMAGE=/pkg/linux/i386-randconfig-h1-06010516/gcc-6/6f2d5395a55901d674b41a9ebe2a03ae28050739/vmlinuz-4.7.0-rc1-00030-g6f2d539 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-vp-quantal-i386/quantal-core-i386.cgz/i386-randconfig-h1-06010516/gcc-6/6f2d5395a55901d674b41a9ebe2a03ae28050739/0 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-vp-quantal-i386-27::dhcp drbd.minor_count=8' -initrd /fs/sde1/initrd-vm-vp-quantal-i386-27 -m 360 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -pidfile /dev/shm/kboot/pid-vm-vp-quantal-i386-27 -serial file:/dev/shm/kboot/serial-vm-vp-quantal-i386-27 -daemonize -display none -monitor null Thanks, Kernel Test Robot