Hi Liviu, 0day kernel testing robot got the below dmesg and the first bad commit is git://git.linaro.org/people/cdall/linux-kvm-arm apm_linux_v3.16-rc1 commit 6f99bc949b1c90ff342a7d44ac4122322a7ccb78 Author: Liviu Dudau AuthorDate: Thu Jun 5 15:20:38 2014 +0530 Commit: Christoffer Dall CommitDate: Fri Jul 11 06:34:50 2014 -0700 pci: Create pci_host_bridge before its associated bus in pci_create_root_bus. Before commit 7b5436635800 the pci_host_bridge was created before the root bus. As that commit has added a needless dependency on the bus for pci_alloc_host_bridge() the creation order has been changed for no good reason. Revert the order of creation as we are going to depend on the pci_host_bridge structure to retrieve the domain number of the root bus. Signed-off-by: Liviu Dudau Acked-by: Grant Likely Tested-by: Tanmay Inamdar +------------------------------------------------------------+------------+------------+ | | 175e014331 | 6f99bc949b | +------------------------------------------------------------+------------+------------+ | boot_successes | 60 | 0 | | boot_failures | 0 | 20 | | BUG:unable_to_handle_kernel_NULL_pointer_dereference | 0 | 20 | | Oops | 0 | 20 | | EIP_is_at_pcibios_root_bridge_prepare | 0 | 20 | | WARNING:CPU:PID:at_kernel/smp.c:smp_call_function_single() | 0 | 20 | | Kernel_panic-not_syncing:Attempted_to_kill_init_exitcode= | 0 | 20 | | backtrace:acpi_bus_scan | 0 | 20 | | backtrace:acpi_scan_init | 0 | 20 | | backtrace:acpi_init | 0 | 20 | | backtrace:kernel_init_freeable | 0 | 20 | +------------------------------------------------------------+------------+------------+ [ 0.351550] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) [ 0.352949] acpi PNP0A03:00: _OSC: OS supports [ASPM ClockPM Segments] [ 0.353402] acpi PNP0A03:00: _OSC failed (AE_NOT_FOUND); disabling ASPM [ 0.355122] BUG: unable to handle kernel NULL pointer dereference at 00000064 [ 0.356666] IP: [] pcibios_root_bridge_prepare+0xe/0x20 [ 0.356666] *pde = 00000000 [ 0.356666] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 0.356666] Modules linked in: [ 0.356666] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.16.0-rc1-00005-g6f99bc9 #2 [ 0.356666] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 0.356666] task: cfc7e010 ti: cfcc0000 task.ti: cfcc0000 [ 0.356666] EIP: 0060:[] EFLAGS: 00010286 CPU: 0 [ 0.356666] EIP is at pcibios_root_bridge_prepare+0xe/0x20 [ 0.356666] EAX: cfe0a000 EBX: c1d83d20 ECX: 00000000 EDX: 00000000 [ 0.356666] ESI: 00000000 EDI: cfe0a000 EBP: cfcc1d20 ESP: cfcc1d20 [ 0.356666] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 [ 0.356666] CR0: 8005003b CR2: 00000064 CR3: 01e77000 CR4: 000006d0 [ 0.356666] Stack: [ 0.356666] cfcc1da4 c13d7a8b cfcc1dd4 cfe56e00 cfcc1dd4 cfe56d40 cfcc1dd4 cfc00180 [ 0.356666] cfcc1d88 c11a77d2 cfe0a184 00000001 00000000 00000000 c1093cf9 00000246 [ 0.356666] 000080d0 00000282 00000010 000080d0 00000020 00000246 c13d5a48 cfcc1dd4 [ 0.356666] Call Trace: [ 0.356666] [] pci_create_root_bus+0x5b/0x340 [ 0.356666] [] ? kmem_cache_alloc_trace+0x3a2/0x4b0 [ 0.356666] [] ? insert_resource_conflict+0x19/0x40 [ 0.356666] [] ? pci_add_resource_offset+0x28/0x60 [ 0.356666] [] ? pci_add_resource_offset+0x28/0x60 [ 0.356666] [] pci_acpi_scan_root+0x25b/0x370 [ 0.356666] [] acpi_pci_root_add+0x223/0x2c9 [ 0.356666] [] ? acpi_bus_get_status_handle+0x18/0x3a [ 0.356666] [] acpi_bus_attach+0xb5/0x160 [ 0.356666] [] ? mutex_unlock+0xd/0x10 [ 0.356666] [] ? device_attach+0x8c/0xa0 [ 0.356666] [] acpi_bus_attach+0x11e/0x160 [ 0.356666] [] ? mutex_unlock+0xd/0x10 [ 0.356666] [] ? device_attach+0x8c/0xa0 [ 0.356666] [] acpi_bus_attach+0x11e/0x160 [ 0.356666] [] acpi_bus_scan+0x49/0x59 [ 0.356666] [] acpi_scan_init+0x5b/0x16b [ 0.356666] [] acpi_init+0x205/0x220 [ 0.356666] [] ? acpi_sleep_proc_init+0x23/0x23 [ 0.356666] [] do_one_initcall+0x7e/0x1b0 [ 0.356666] [] ? acpi_sleep_proc_init+0x23/0x23 [ 0.356666] [] ? initcall_blacklist+0x23/0x81 [ 0.356666] [] ? parse_args+0x1d9/0x360 [ 0.356666] [] ? __usermodehelper_set_disable_depth+0x41/0x50 [ 0.356666] [] kernel_init_freeable+0x1b2/0x249 [ 0.356666] [] ? initcall_blacklist+0x81/0x81 [ 0.356666] [] kernel_init+0x10/0xe0 [ 0.356666] [] ret_from_kernel_thread+0x21/0x30 [ 0.356666] [] ? rest_init+0x130/0x130 [ 0.356666] Code: 8b 45 e0 89 44 24 04 e8 26 ab 19 00 31 c0 e9 8f fd ff ff 8d 76 00 8d bc 27 00 00 00 00 55 89 e5 3e 8d 74 26 00 8b 90 80 01 00 00 <8b> 52 64 8b 52 08 89 90 28 01 00 00 31 c0 5d c3 66 90 55 89 e5 [ 0.356666] EIP: [] pcibios_root_bridge_prepare+0xe/0x20 SS:ESP 0068:cfcc1d20 [ 0.356666] CR2: 0000000000000064 [ 0.356666] ---[ end trace 849b10f6fad5eb6f ]--- [ 0.356666] ------------[ cut here ]------------ git bisect start 263df82c9fb5fc5b3504d294f7ab813c274bf1d1 7171511eaec5bf23fb06078f59784a3a0626b38f -- git bisect bad 56485a95d9ffdb6b431ea00171e320112a992b40 # 01:09 0- 9 rtc: Fix suspend/resume for APM X-Gene SoC RTC driver git bisect bad 2a146bde9a2b55d8d9e98a1f4b72ca694aa67879 # 01:22 0- 19 dt-bindings: pci: xgene pcie device tree bindings git bisect bad 6f99bc949b1c90ff342a7d44ac4122322a7ccb78 # 02:11 0- 1 pci: Create pci_host_bridge before its associated bus in pci_create_root_bus. git bisect good d1eee6a841dd73ecd3cce0e70686152cc5789c91 # 02:14 20+ 0 arm64: Add architecture support for PCI git bisect good ab84a1c5bef2092f87cf22239df5592c68a83978 # 02:17 20+ 0 pci: Introduce pci_register_io_range() helper function. git bisect good 175e0143313927c52fd7b6b5b66c202e3d6ab31c # 02:39 20+ 0 pci: OF: Fix the conversion of IO ranges into IO resources. # first bad commit: [6f99bc949b1c90ff342a7d44ac4122322a7ccb78] pci: Create pci_host_bridge before its associated bus in pci_create_root_bus. git bisect good 175e0143313927c52fd7b6b5b66c202e3d6ab31c # 02:40 60+ 0 pci: OF: Fix the conversion of IO ranges into IO resources. git bisect bad 263df82c9fb5fc5b3504d294f7ab813c274bf1d1 # 02:40 0- 11 arm64: Add defconfig and dts for Xen on APM X-Gene Mustang board git bisect good 67b9d76f9e2f9f87f94a11521cc996dc2e43ce14 # 02:45 60+ 0 Merge tag 'dm-3.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm git bisect good b7079aa6ab3e23d080fa9b79d7f414d8287c32b4 # 02:48 60+ 0 Add linux-next specific files for 20140711 This script may reproduce the error. ---------------------------------------------------------------------------- #!/bin/bash kernel=$1 kvm=( qemu-system-x86_64 -cpu kvm64 -enable-kvm -kernel $kernel -m 320 -smp 2 -net nic,vlan=1,model=e1000 -net user,vlan=1 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -serial stdio -display none -monitor null ) append=( hung_task_panic=1 earlyprintk=ttyS0,115200 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=10 softlockup_panic=1 nmi_watchdog=panic prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal root=/dev/ram0 rw drbd.minor_count=8 ) "${kvm[@]}" --append "${append[*]}" ---------------------------------------------------------------------------- Thanks, Jet