FYI, we noticed the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git x86/vmap_stack commit 33c4f826f210da9ea4f198dea266f425f13615e9 ("x86: Move addr_limit to thread_struct") on test machine: vm-vp-quantal-x86_64: 2 threads qemu-system-x86_64 -enable-kvm with 360M memory caused below changes: +--------------------------------------------------+------------+------------+ | | 59927176f3 | 33c4f826f2 | +--------------------------------------------------+------------+------------+ | boot_successes | 22 | 0 | | boot_failures | 1 | 45 | | BUG:kernel_test_crashed | 1 | | | INFO:task_blocked_for_more_than#seconds | 0 | 29 | | RIP:__default_send_IPI_dest_field | 0 | 29 | | RIP:native_safe_halt | 0 | 17 | | Kernel_panic-not_syncing:hung_task:blocked_tasks | 0 | 29 | | backtrace:misc_register | 0 | 45 | | backtrace:vga_arb_device_init | 0 | 45 | | backtrace:kernel_init_freeable | 0 | 45 | | backtrace:watchdog | 0 | 29 | | backtrace:cpu_startup_entry | 0 | 5 | | general_protection_fault:#[##]SMP | 0 | 16 | | RIP:__lock_acquire | 0 | 16 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 16 | | RIP:lock_time_inc | 0 | 1 | +--------------------------------------------------+------------+------------+ [ 1.581053] ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11) [ 1.583300] ACPI: PCI Interrupt Link [LNKS] (IRQs *9) [ 1.590883] ACPI: Enabled 16 GPEs in block 00 to 0F [ 244.074282] INFO: task swapper/0:1 blocked for more than 120 seconds. [ 244.082592] Not tainted 4.7.0-rc3-00015-g33c4f82 #353 [ 244.084853] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 244.088477] swapper/0 D ffff880013bf3af8 12600 1 0 0x00000000 [ 244.091658] ffff880013bf3af8 00ff880013be88a0 ffffffff00000001 ffff880013dd7500 [ 244.096323] ffff880013dd7518 ffff880013be8040 ffff880013bf4000 7fffffffffffffff [ 244.100521] ffff880013bf3c98 0000000000000002 ffff880013be8040 ffff880013bf3b10 [ 244.104673] Call Trace: [ 244.106316] [<ffffffff81cc79f5>] schedule+0x88/0x9d [ 244.108431] [<ffffffff81ccb462>] schedule_timeout+0x3f/0x31d [ 244.110827] [<ffffffff8108bcf5>] ? kvm_sched_clock_read+0x9/0x12 [ 244.113350] [<ffffffff8106ab51>] ? sched_clock+0x9/0xd [ 244.115521] [<ffffffff810ea679>] ? mark_held_locks+0x5e/0x74 [ 244.117775] [<ffffffff81ccc227>] ? _raw_spin_unlock_irq+0x2c/0x3d [ 244.120637] [<ffffffff810ea80d>] ? trace_hardirqs_on_caller+0x17e/0x19a [ 244.123573] [<ffffffff81cc833e>] wait_for_common+0x114/0x153 [ 244.126302] [<ffffffff81cc833e>] ? wait_for_common+0x114/0x153 [ 244.128606] [<ffffffff810ca6bd>] ? wake_up_q+0x56/0x56 [ 244.130880] [<ffffffff81cc839a>] wait_for_completion+0x1d/0x1f [ 244.133433] [<ffffffff817442b0>] devtmpfs_create_node+0x109/0x126 [ 244.136261] [<ffffffff81cc826e>] ? wait_for_common+0x44/0x153 [ 244.138847] [<ffffffff8173b538>] device_add+0x3d6/0x50f [ 244.141359] [<ffffffff811b4926>] ? kfree_const+0x20/0x22 [ 244.143578] [<ffffffff8173b805>] device_create_groups_vargs+0xb8/0xed [ 244.146024] [<ffffffff827b1831>] ? set_debug_rodata+0x12/0x12 [ 244.148413] [<ffffffff8173b8bd>] device_create_with_groups+0x30/0x32 [ 244.151425] [<ffffffff827b1831>] ? set_debug_rodata+0x12/0x12 [ 244.158945] [<ffffffff81650668>] misc_register+0xb8/0x121 [ 244.161127] [<ffffffff82802806>] ? trace_event_define_fields_i915_gem_object_pwrite+0x88/0x88 [ 244.164800] [<ffffffff82802820>] vga_arb_device_init+0x1a/0x1a7 [ 244.167026] [<ffffffff82802806>] ? trace_event_define_fields_i915_gem_object_pwrite+0x88/0x88 [ 244.169677] [<ffffffff827b1831>] ? set_debug_rodata+0x12/0x12 [ 244.171836] [<ffffffff8100042b>] do_one_initcall+0x90/0x123 [ 244.173729] [<ffffffff827b1831>] ? set_debug_rodata+0x12/0x12 [ 244.175680] [<ffffffff827b20d0>] kernel_init_freeable+0x1cf/0x257 [ 244.177344] [<ffffffff81cbea12>] kernel_init+0xe/0xf5 [ 244.178838] [<ffffffff81cccc2f>] ret_from_fork+0x1f/0x40 [ 244.180374] [<ffffffff81cbea04>] ? rest_init+0x13b/0x13b [ 244.181915] 1 lock held by swapper/0/1: [ 244.183210] #0: (misc_mtx){+.+.+.}, at: [<ffffffff816505de>] misc_register+0x2e/0x121 [ 244.186232] Sending NMI to all CPUs: [ 244.187630] NMI backtrace for cpu 0 [ 244.189322] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc3-00015-g33c4f82 #353 [ 244.192239] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 244.195870] task: ffffffff8241d540 ti: ffffffff82400000 task.ti: ffffffff82400000 [ 244.198984] RIP: 0010:[<ffffffff8108c10f>] [<ffffffff8108c10f>] native_safe_halt+0x6/0x8 [ 244.248149] RSP: 0000:ffffffff82403eb0 EFLAGS: 00000202 [ 244.249658] RAX: ffffffff8241d540 RBX: 0000000000000000 RCX: 0000000000000003 [ 244.251441] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8241d540 [ 244.271341] RBP: ffffffff82403eb0 R08: 0000004df88fedb8 R09: 0000000000000001 [ 244.273148] R10: ffffffff82403e28 R11: ffffffff810c12ee R12: 0000000000000000 [ 244.274933] R13: 0000000000000000 R14: ffffffff82400000 R15: ffffffff82400000 [ 244.276722] FS: 0000000000000000(0000) GS:ffff880013c00000(0000) knlGS:0000000000000000 [ 244.279237] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 244.289843] CR2: 00000000ffffffff CR3: 0000000002418000 CR4: 00000000000006f0 [ 244.291638] Stack: [ 244.292631] ffffffff82403ed8 ffffffff8106b8f0 0000000000000000 ffffffff82400000 [ 244.295036] 0000000000000000 ffffffff82403ee8 ffffffff8106c168 ffffffff82403ef8 [ 244.297449] ffffffff810e0f6f ffffffff82403f38 ffffffff810e1188 ffffffff82404000 [ 244.317920] Call Trace: [ 244.318985] [<ffffffff8106b8f0>] default_idle+0x62/0x1b0 [ 244.320506] [<ffffffff8106c168>] arch_cpu_idle+0xf/0x11 [ 244.322013] [<ffffffff810e0f6f>] default_idle_call+0x3d/0x44 [ 244.323586] [<ffffffff810e1188>] cpu_startup_entry+0x212/0x3e2 [ 244.337259] [<ffffffff81cbe9fe>] rest_init+0x135/0x13b [ 244.338779] [<ffffffff827b1ef4>] start_kernel+0x404/0x411 [ 244.340306] [<ffffffff827b1120>] ? early_idt_handler_array+0x120/0x120 [ 244.342023] [<ffffffff827b129e>] x86_64_start_reservations+0x2f/0x31 [ 244.343695] [<ffffffff827b13de>] x86_64_start_kernel+0x13e/0x14d [ 244.345315] Code: 48 89 e5 0f 09 5d c3 55 48 89 e5 9c 58 5d c3 55 48 89 e5 57 9d 5d c3 55 48 89 e5 fa 5d c3 55 48 89 e5 fb 5d c3 55 48 89 e5 fb f4 <5d> c3 55 48 89 e5 f4 5d c3 55 49 89 c9 49 89 d0 8b 07 48 89 e5 [ 244.372091] NMI backtrace for cpu 1 [ 244.373272] CPU: 1 PID: 646 Comm: khungtaskd Not tainted 4.7.0-rc3-00015-g33c4f82 #353 [ 244.375660] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 244.378733] task: ffff8800132d8040 ti: ffff8800133f8000 task.ti: ffff8800133f8000 [ 244.381788] RIP: 0010:[<ffffffff8108147d>] [<ffffffff8108147d>] __default_send_IPI_dest_field+0x5d/0x63 [ 244.385251] RSP: 0000:ffff8800133fbd60 EFLAGS: 00000046 [ 244.387351] RAX: 0000000000000000 RBX: 0000000000000c00 RCX: ffff8800132d8040 [ 244.389969] RDX: 0000000000000c00 RSI: 0000000000000002 RDI: 0000000003000000 [ 244.392216] RBP: ffff8800133fbd78 R08: 0000000000000001 R09: 0000000000000000 [ 244.394055] R10: ffffffff830dc8e0 R11: 00000000000fffa0 R12: 0000000000000001 [ 244.395922] R13: 0000000000000002 R14: ffff880013be83d0 R15: 00000000000003ff [ 244.397787] FS: 0000000000000000(0000) GS:ffff880013e00000(0000) knlGS:0000000000000000 [ 244.400415] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 244.402039] CR2: 00000000ffffffff CR3: 0000000002418000 CR4: 00000000000006e0 [ 244.404226] Stack: [ 244.405642] 00000003132d8040 0000000000000286 ffffffff81082459 ffff8800133fbda0 [ 244.409074] ffffffff81084d98 0000000000000003 000000028224a083 0000000000000001 [ 244.412578] ffff8800133fbdb0 ffffffff81084e5c ffff8800133fbdc0 ffffffff81082474 [ 244.416026] Call Trace: [ 244.417498] [<ffffffff81082459>] ? irq_force_complete_move+0x100/0x100 [ 244.419459] [<ffffffff81084d98>] _flat_send_IPI_mask+0x41/0x6c [ 244.420992] [<ffffffff81084e5c>] flat_send_IPI_mask+0x11/0x13 [ 244.422534] [<ffffffff81082474>] nmi_raise_cpu_backtrace+0x1b/0x1d [ 244.424119] [<ffffffff8155e77c>] nmi_trigger_all_cpu_backtrace+0xa6/0xe2 [ 244.425882] [<ffffffff810824a5>] arch_trigger_all_cpu_backtrace+0x19/0x1b [ 244.428337] [<ffffffff81155709>] watchdog+0x4aa/0x58d [ 244.430337] [<ffffffff8115525f>] ? reset_hung_task_detector+0x15/0x15 [ 244.432707] [<ffffffff810c0033>] kthread+0xfb/0x103 [ 244.435934] [<ffffffff81cccc2f>] ret_from_fork+0x1f/0x40 [ 244.441229] [<ffffffff810bff38>] ? kthread_create_on_node+0x1ca/0x1ca [ 244.443418] Code: ff 0f ba e0 0c 73 04 f3 90 eb ef c1 e7 18 89 3c 25 10 d3 5f ff 44 89 ea 09 da 80 cf 04 41 83 fd 02 0f 44 d3 89 14 25 00 d3 5f ff <58> 5b 41 5d 5d c3 0f 1f 44 00 00 55 48 89 e5 41 54 4c 63 e7 53 [ 244.449990] Kernel panic - not syncing: hung_task: blocked tasks [ 244.452088] CPU: 1 PID: 646 Comm: khungtaskd Not tainted 4.7.0-rc3-00015-g33c4f82 #353 [ 244.454867] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 244.457602] 0000000000000000 ffff8800133fbd78 ffffffff8155a9ad ffffffff8220c086 [ 244.460631] ffff8800133fbe08 ffff8800133fbdf8 ffffffff81193ace ffff880000000008 [ 244.464064] ffff8800133fbe08 ffff8800133fbda0 ffffffff810fd7f8 0000000000000000 [ 244.466985] Call Trace: [ 244.468105] [<ffffffff8155a9ad>] dump_stack+0x86/0xc0 [ 244.469549] [<ffffffff81193ace>] panic+0xd7/0x21e [ 244.471889] [<ffffffff810fd7f8>] ? printk_nmi_flush+0x32/0x88 [ 244.473450] [<ffffffff81155715>] watchdog+0x4b6/0x58d [ 244.474941] [<ffffffff8115525f>] ? reset_hung_task_detector+0x15/0x15 [ 244.477126] [<ffffffff810c0033>] kthread+0xfb/0x103 [ 244.479144] [<ffffffff81cccc2f>] ret_from_fork+0x1f/0x40 [ 244.481339] [<ffffffff810bff38>] ? kthread_create_on_node+0x1ca/0x1ca Elapsed time: 250 qemu-system-x86_64 -enable-kvm -kernel /pkg/linux/x86_64-nfsroot/gcc-6/33c4f826f210da9ea4f198dea266f425f13615e9/vmlinuz-4.7.0-rc3-00015-g33c4f82 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-vp-quantal-x86_64-35/bisect_boot-1-quantal-core-x86_64.cgz-x86_64-nfsroot-33c4f826f210da9ea4f198dea266f425f13615e9-20160617-28771-184jeog-1.yaml~ ARCH=x86_64 kconfig=x86_64-nfsroot branch=linux-devel/devel-catchup-201606170800 commit=33c4f826f210da9ea4f198dea266f425f13615e9 BOOT_IMAGE=/pkg/linux/x86_64-nfsroot/gcc-6/33c4f826f210da9ea4f198dea266f425f13615e9/vmlinuz-4.7.0-rc3-00015-g33c4f82 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-vp-quantal-x86_64/quantal-core-x86_64.cgz/x86_64-nfsroot/gcc-6/33c4f826f210da9ea4f198dea266f425f13615e9/0 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-x86_64-35::dhcp drbd.minor_count=8' -initrd /fs/sdf1/initrd-vm-vp-quantal-x86_64-35 -m 360 -smp 2 -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-x86_64-35 -serial file:/dev/shm/kboot/serial-vm-vp-quantal-x86_64-35 -daemonize -display none -monitor null FYI, raw QEMU command line is: qemu-system-x86_64 -enable-kvm -kernel /pkg/linux/x86_64-nfsroot/gcc-6/33c4f826f210da9ea4f198dea266f425f13615e9/vmlinuz-4.7.0-rc3-00015-g33c4f82 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-vp-quantal-x86_64-35/bisect_boot-1-quantal-core-x86_64.cgz-x86_64-nfsroot-33c4f826f210da9ea4f198dea266f425f13615e9-20160617-28771-184jeog-1.yaml~ ARCH=x86_64 kconfig=x86_64-nfsroot branch=linux-devel/devel-catchup-201606170800 commit=33c4f826f210da9ea4f198dea266f425f13615e9 BOOT_IMAGE=/pkg/linux/x86_64-nfsroot/gcc-6/33c4f826f210da9ea4f198dea266f425f13615e9/vmlinuz-4.7.0-rc3-00015-g33c4f82 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-vp-quantal-x86_64/quantal-core-x86_64.cgz/x86_64-nfsroot/gcc-6/33c4f826f210da9ea4f198dea266f425f13615e9/0 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-x86_64-35::dhcp drbd.minor_count=8' -initrd /fs/sdf1/initrd-vm-vp-quantal-x86_64-35 -m 360 -smp 2 -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-x86_64-35 -serial file:/dev/shm/kboot/serial-vm-vp-quantal-x86_64-35 -daemonize -display none -monitor null Thanks, Kernel Test Robot