FYI, we noticed the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git x86/uaccess commit 6ce52d535e1adcfb44ffd9e5503081805d33aa87 ("x86/uaccess: OOPS or warn on a fault with KERNEL_DS and !pagefault_disabled()") on test machine: vm-kbuild-yocto-x86_64: 1 threads qemu-system-x86_64 -enable-kvm -cpu SandyBridge with 320M memory caused below changes: +------------------------------------------+------------+------------+ | | 0390fec2cd | 6ce52d535e | +------------------------------------------+------------+------------+ | boot_successes | 63 | 0 | | boot_failures | 0 | 48 | | BUG:uaccess_fault_at#with_KERNEL_DS | 0 | 48 | | BUG:unable_to_handle_kernel | 0 | 48 | | Oops | 0 | 48 | | RIP:copy_mount_options | 0 | 48 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 48 | | backtrace:SyS_mount | 0 | 48 | | backtrace:devtmpfsd | 0 | 48 | +------------------------------------------+------------+------------+ [ 0.521415] apic 0 pin 23 not connected [ 0.522223] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 [ 0.523489] TSC deadline timer enabled [ 0.524471] BUG: uaccess fault at 0xffff880013588000 with KERNEL_DS [ 0.525442] BUG: unable to handle kernel paging request at ffff880013588000 [ 0.526588] IP: [<ffffffff811b1448>] copy_mount_options+0xde/0x18b [ 0.527571] PGD 42d3067 PUD 42d4067 PMD 13966067 PTE 8000000013588060 [ 0.528658] Oops: 0000 [#1] DEBUG_PAGEALLOC [ 0.529304] CPU: 0 PID: 9 Comm: kdevtmpfs Not tainted 4.7.0-rc3-00007-g6ce52d5 #2 [ 0.530482] task: ffff880013580000 ti: ffff880013584000 task.ti: ffff880013584000 [ 0.531635] task.addr_limit: 0xffffffffffffffff [ 0.532331] RIP: 0010:[<ffffffff811b1448>] [<ffffffff811b1448>] copy_mount_options+0xde/0x18b [ 0.533683] RSP: 0000:ffff880013587d70 EFLAGS: 00010246 [ 0.534506] RAX: 0000000000000000 RBX: 0000000000001000 RCX: ffff880013587a50 [ 0.535596] RDX: ffff880013580000 RSI: 8000000013573163 RDI: 0000000000000282 [ 0.536687] RBP: ffff880013587da0 R08: 0000000000001000 R09: 0000000000000000 [ 0.537778] R10: ffff880013587b20 R11: 000000000000066d R12: 0000000000000e06 [ 0.538871] R13: ffff880013573000 R14: ffff880013587e06 R15: ffff880013588000 [ 0.539965] FS: 0000000000000000(0000) GS:ffffffff82223000(0000) knlGS:0000000000000000 [ 0.541217] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.542101] CR2: ffff880013588000 CR3: 000000000220d000 CR4: 00000000000406b0 [ 0.543189] Stack: [ 0.543518] ffff8800135731fa ffffffff81f7e280 ffff88001354f7f0 ffff88001354f918 [ 0.544735] ffff880013587e06 0000000000008000 ffff880013587dd8 ffffffff811b24cb [ 0.545955] ffff88001351bee4 ffff88001351bdb0 ffff88001351bee4 ffffffff815c512d [ 0.547170] Call Trace: [ 0.547570] [<ffffffff811b24cb>] SyS_mount+0x70/0xd5 [ 0.548358] [<ffffffff815c512d>] ? handle_create+0x237/0x237 [ 0.549238] [<ffffffff815c5192>] devtmpfsd+0x65/0x1d2 [ 0.550041] [<ffffffff81b61451>] ? __schedule+0x541/0x615 [ 0.550911] [<ffffffff815c512d>] ? handle_create+0x237/0x237 [ 0.551802] [<ffffffff810ce680>] kthread+0xdd/0xec [ 0.552565] [<ffffffff81014a13>] ? sched_clock+0x9/0xb [ 0.553380] [<ffffffff810d3600>] ? finish_task_switch+0xf4/0x18b [ 0.554319] [<ffffffff81b65b8f>] ret_from_fork+0x1f/0x40 [ 0.555151] [<ffffffff810ce5a3>] ? init_completion+0x2d/0x2d [ 0.556034] Code: ff ff 72 0a e8 02 bd f6 ff 4d 39 e7 73 0a e8 f8 bc f6 ff 49 89 dc eb 5b 4c 89 6d d0 49 89 dc eb 3a e8 e5 bc f6 ff 66 66 90 31 c0 <45> 8a 3f 66 66 90 85 c0 74 12 e8 d1 bc f6 ff 48 8b 7d d0 44 89 [ 0.560326] RIP [<ffffffff811b1448>] copy_mount_options+0xde/0x18b [ 0.561325] RSP <ffff880013587d70> [ 0.561871] CR2: ffff880013588000 [ 0.562401] ---[ end trace 3c4cbff2ef96e4e2 ]--- [ 0.563111] Kernel panic - not syncing: Fatal exception FYI, raw QEMU command line is: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -kernel /pkg/linux/x86_64-randconfig-s1-06140547/gcc-6/6ce52d535e1adcfb44ffd9e5503081805d33aa87/vmlinuz-4.7.0-rc3-00007-g6ce52d5 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-kbuild-yocto-x86_64-39/rand_boot-1-yocto-minimal-x86_64.cgz-x86_64-randconfig-s1-06140547-6ce52d535e1adcfb44ffd9e5503081805d33aa87-20160614-75208-1fm6u3i-0.yaml~ ARCH=x86_64 kconfig=x86_64-randconfig-s1-06140547 branch=linux-devel/devel-spot-201606140509 commit=6ce52d535e1adcfb44ffd9e5503081805d33aa87 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-s1-06140547/gcc-6/6ce52d535e1adcfb44ffd9e5503081805d33aa87/vmlinuz-4.7.0-rc3-00007-g6ce52d5 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-kbuild-yocto-x86_64/yocto-minimal-x86_64.cgz/x86_64-randconfig-s1-06140547/gcc-6/6ce52d535e1adcfb44ffd9e5503081805d33aa87/0 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-x86_64-39::dhcp drbd.minor_count=8' -initrd /fs/sdh1/initrd-vm-kbuild-yocto-x86_64-39 -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/sdh1/disk0-vm-kbuild-yocto-x86_64-39,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-kbuild-yocto-x86_64-39 -serial file:/dev/shm/kboot/serial-vm-kbuild-yocto-x86_64-39 -daemonize -display none -monitor null Thanks, Kernel Test Robot