FYI, we noticed the below changes on https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git wb-buf-throttle commit e7b81af035ddc1323090d86350627881fcf9b1b0 ("blk-wb: updates") +----------------------------------------------------------------------------------------+------------+------------+ | | 2adccca124 | e7b81af035 | +----------------------------------------------------------------------------------------+------------+------------+ | boot_successes | 3 | 2 | | boot_failures | 1 | 6 | | page_allocation_failure:order:#,mode:#(GFP_NOWAIT|__GFP_HIGH|__GFP_COMP|__GFP_NOTRACK) | 1 | | | warn_alloc_failed+0x | 1 | | | Mem-Info | 1 | | | backtrace:do_execveat_common | 1 | | | backtrace:compat_SyS_execve | 1 | | | backtrace:compat_process_vm_rw | 1 | | | backtrace:compat_SyS_process_vm_writev | 1 | | | BUG:unable_to_handle_kernel | 0 | 6 | | Oops | 0 | 6 | | RIP:blk_wb_done | 0 | 6 | | Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 0 | 6 | | backtrace:cpu_startup_entry | 0 | 3 | | backtrace:schedule_preempt_disabled | 0 | 1 | +----------------------------------------------------------------------------------------+------------+------------+ [ 17.486381] FDC 0 is a S82078B [ 17.557276] brd: module loaded [ 17.602156] loop: module loaded [ 17.612220] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0 [ 17.614651] IP: [] blk_wb_done+0x18/0x8e [ 17.616135] PGD 0 [ 17.617105] Oops: 0000 [#1] SMP [ 17.618343] Modules linked in: [ 17.619459] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.6.0-rc1-00096-ge7b81af #1 [ 17.621643] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 17.624034] task: ffffffff8241d540 ti: ffffffff82400000 task.ti: ffffffff82400000 [ 17.626211] RIP: 0010:[] [] blk_wb_done+0x18/0x8e [ 17.628556] RSP: 0018:ffff880038803df8 EFLAGS: 00010046 [ 17.629923] RAX: ffff88003e550008 RBX: 0000000000000000 RCX: ffff88003880cf20 [ 17.631540] RDX: ef7bdef7bdef7bdf RSI: ffff88003e4a0000 RDI: 0000000000000000 [ 17.633175] RBP: ffff880038803e08 R08: 00000000e272d5c3 R09: 0000000000000004 [ 17.634807] R10: ffff880038803d78 R11: ffff880038808000 R12: ffff88003e4a0000 [ 17.636426] R13: ffffe8ffffc07800 R14: 0000000000000000 R15: 0000000000000001 [ 17.638053] FS: 0000000000000000(0000) GS:ffff880038800000(0000) knlGS:0000000000000000 [ 17.640324] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 17.641740] CR2: 00000000000000a0 CR3: 0000000002418000 CR4: 00000000000006f0 [ 17.643381] Stack: [ 17.644273] ffff88003e4a0000 0000000000000000 ffff880038803e28 ffffffff8152fa30 [ 17.646792] ffff88003e4a0000 0000000000000000 ffff880038803e38 ffffffff81755005 [ 17.649300] ffff880038803e68 ffffffff8152fcef 0000000000000000 ffff88003e974548 [ 17.651805] Call Trace: [ 17.652740] [ 17.653108] [] blk_mq_end_request+0x38/0x6c [ 17.655190] [] virtblk_request_done+0x5e/0x60 [ 17.656660] [] __blk_mq_complete_request+0x122/0x132 [ 17.658222] [] blk_mq_complete_request+0x1c/0x1e [ 17.659724] [] virtblk_done+0x74/0xce [ 17.661118] [] vring_interrupt+0x32/0x39 [ 17.662525] [] handle_irq_event_percpu+0x146/0x3d7 [ 17.664060] [] handle_irq_event+0x38/0x56 [ 17.665463] [] handle_edge_irq+0xd9/0xfb [ 17.666872] [] handle_irq+0x101/0x109 [ 17.668246] [] do_IRQ+0x85/0x101 [ 17.669550] [] common_interrupt+0x8c/0x8c [ 17.671071] [ 17.671434] [] ? native_safe_halt+0x6/0x8 [ 17.673485] [] default_idle+0x60/0x1a8 [ 17.674935] [] arch_cpu_idle+0xf/0x11 [ 17.676307] [] default_idle_call+0x3d/0x44 [ 17.677736] [] cpu_startup_entry+0x218/0x3e6 [ 17.679209] [] rest_init+0x135/0x13b [ 17.680585] [] start_kernel+0x3fd/0x40a [ 17.682013] [] ? early_idt_handler_array+0x120/0x120 [ 17.683562] [] x86_64_start_reservations+0x2a/0x2c [ 17.685086] [] x86_64_start_kernel+0x138/0x145 [ 17.686551] Code: 31 c9 ba 01 00 00 00 be 03 00 00 00 e8 cc ad ba ff 5d c3 66 66 66 66 90 55 48 89 e5 41 54 49 89 f4 53 f6 46 44 08 48 89 fb 75 30 <48> 3b b7 a0 00 00 00 75 16 48 c7 87 98 00 00 00 00 00 00 00 48 [ 17.696365] RIP [] blk_wb_done+0x18/0x8e [ 17.697883] RSP [ 17.698973] CR2: 00000000000000a0 [ 17.700049] ---[ end trace 659ecaf881160b6f ]--- [ 17.701310] Kernel panic - not syncing: Fatal exception in interrupt vm-lkp-wsx03-1G: 1 threads qemu-system-x86_64 -enable-kvm -cpu host with 1G memory FYI, raw QEMU command line is: qemu-system-x86_64 -enable-kvm -cpu host -kernel /pkg/linux/x86_64-nfsroot/gcc-5/e7b81af035ddc1323090d86350627881fcf9b1b0/vmlinuz-4.6.0-rc1-00096-ge7b81af -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-lkp-wsx03-1G-2/bisect_rcutorture-300s-debian-x86_64-2015-02-07.cgz-x86_64-nfsroot-e7b81af035ddc1323090d86350627881fcf9b1b0-20160418-76494-m2ovnl-0.yaml ARCH=x86_64 kconfig=x86_64-nfsroot branch=linux-devel/devel-catchup-201604180356 commit=e7b81af035ddc1323090d86350627881fcf9b1b0 BOOT_IMAGE=/pkg/linux/x86_64-nfsroot/gcc-5/e7b81af035ddc1323090d86350627881fcf9b1b0/vmlinuz-4.6.0-rc1-00096-ge7b81af max_uptime=1500 RESULT_ROOT=/result/rcutorture/300s/vm-lkp-wsx03-1G/debian-x86_64-2015-02-07.cgz/x86_64-nfsroot/gcc-5/e7b81af035ddc1323090d86350627881fcf9b1b0/0 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-lkp-wsx03-1G-2::dhcp' -initrd /fs/sdc1/initrd-vm-lkp-wsx03-1G-2 -m 1024 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0,hostfwd=tcp::23601-:22 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sdc1/disk0-vm-lkp-wsx03-1G-2,media=disk,if=virtio -drive file=/fs/sdc1/disk1-vm-lkp-wsx03-1G-2,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-lkp-wsx03-1G-2 -serial file:/dev/shm/kboot/serial-vm-lkp-wsx03-1G-2 -daemonize -display none -monitor null To reproduce: git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git cd lkp-tests bin/lkp install job.yaml # job file is attached in this email bin/lkp run job.yaml Thanks, Kernel Test Robot