Greetings, 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 | 2af469d82f | +---------------------------------------------------------+------------+------------+------------+ | boot_successes | 65 | 0 | 0 | | boot_failures | 15 | 20 | 11 | | WARNING:CPU:PID:at_mm/early_ioremap.c:__early_ioremap() | 15 | 20 | 10 | | backtrace:acpi_initialize_tables | 15 | 20 | 10 | | backtrace:acpi_table_init | 15 | 20 | 10 | | backtrace:acpi_boot_table_init | 15 | 20 | 10 | | BUG:unable_to_handle_kernel_NULL_pointer_dereference | 0 | 20 | 11 | | Oops | 0 | 20 | 11 | | EIP_is_at_pcibios_root_bridge_prepare | 0 | 20 | 11 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 20 | 11 | | backtrace:pcibios_scan_root | 0 | 20 | 10 | | backtrace:pci_legacy_init | 0 | 20 | 10 | | backtrace:pci_subsys_init | 0 | 20 | 10 | | backtrace:kernel_init_freeable | 0 | 20 | 11 | | backtrace:acpi_bus_scan | 0 | 0 | 1 | | backtrace:acpi_scan_init | 0 | 0 | 1 | | backtrace:acpi_init | 0 | 0 | 1 | +---------------------------------------------------------+------------+------------+------------+ [ 0.167350] PCI: Probing PCI hardware [ 0.167350] PCI: Probing PCI hardware [ 0.168140] PCI: root bus 00: using default resources [ 0.168140] PCI: root bus 00: using default resources [ 0.169232] PCI: Probing PCI hardware (bus 00) [ 0.169232] PCI: Probing PCI hardware (bus 00) [ 0.170009] BUG: unable to handle kernel [ 0.170009] BUG: unable to handle kernel NULL pointer dereferenceNULL pointer dereference at 00000064 at 00000064 [ 0.171553] IP: [ 0.171553] IP: [<41726569>] pcibios_root_bridge_prepare+0x9/0x20 [<41726569>] pcibios_root_bridge_prepare+0x9/0x20 [ 0.172863] *pde = 00000000 [ 0.172863] *pde = 00000000 [ 0.173498] Oops: 0000 [#1] [ 0.173498] Oops: 0000 [#1] DEBUG_PAGEALLOCDEBUG_PAGEALLOC [ 0.174407] CPU: 0 PID: 1 Comm: swapper Tainted: G W 3.16.0-rc1-00005-g6f99bc9 #1 [ 0.174407] CPU: 0 PID: 1 Comm: swapper Tainted: G W 3.16.0-rc1-00005-g6f99bc9 #1 [ 0.176197] task: 40020d50 ti: 40022000 task.ti: 40022000 [ 0.176197] task: 40020d50 ti: 40022000 task.ti: 40022000 [ 0.177338] EIP: 0060:[<41726569>] EFLAGS: 00010206 CPU: 0 [ 0.177338] EIP: 0060:[<41726569>] EFLAGS: 00010206 CPU: 0 [ 0.178508] EIP is at pcibios_root_bridge_prepare+0x9/0x20 [ 0.178508] EIP is at pcibios_root_bridge_prepare+0x9/0x20 [ 0.179660] EAX: 40076c00 EBX: 40060880 ECX: 00000000 EDX: 00000000 [ 0.179660] EAX: 40076c00 EBX: 40060880 ECX: 00000000 EDX: 00000000 [ 0.180000] ESI: 40076c00 EDI: 00000000 EBP: 40023e14 ESP: 40023e14 [ 0.180000] ESI: 40076c00 EDI: 00000000 EBP: 40023e14 ESP: 40023e14 [ 0.180000] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 [ 0.180000] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 [ 0.180000] CR0: 8005003b CR2: 00000064 CR3: 01cd8000 CR4: 000006d0 [ 0.180000] CR0: 8005003b CR2: 00000064 CR3: 01cd8000 CR4: 000006d0 git bisect start 2af469d82fdf68c8315d47c424c614f097f34bfe c77dcacb397519b6ade8f08201a4a90a7f4f751e -- git bisect good e854c688381e070be212422fce2cea1fb9d7c2ef # 20:39 20+ 5 arm/arm64: KVM: vgic: Improve handling of GICD_I{CS}PENDRn git bisect good 1b233bf6034bea4b76c8c0b17e4efd5971689ca9 # 20:44 20+ 0 arm/arm64: KVM: vgic: Clarify and correct vgic documentation git bisect good e216fd3bc192cc5aadac841938d1eb4c8911d30f # 20:47 20+ 0 WIP: arm/arm64: KVM: Implement support for unqueueing active interrupts git bisect bad 56485a95d9ffdb6b431ea00171e320112a992b40 # 20:50 0- 20 rtc: Fix suspend/resume for APM X-Gene SoC RTC driver git bisect bad 2a146bde9a2b55d8d9e98a1f4b72ca694aa67879 # 20:53 0- 20 dt-bindings: pci: xgene pcie device tree bindings git bisect bad 6f99bc949b1c90ff342a7d44ac4122322a7ccb78 # 20:56 0- 20 pci: Create pci_host_bridge before its associated bus in pci_create_root_bus. git bisect good d1eee6a841dd73ecd3cce0e70686152cc5789c91 # 21:01 20+ 20 arm64: Add architecture support for PCI git bisect good 175e0143313927c52fd7b6b5b66c202e3d6ab31c # 21:05 20+ 15 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 # 21:07 60+ 15 pci: OF: Fix the conversion of IO ranges into IO resources. git bisect bad 2af469d82fdf68c8315d47c424c614f097f34bfe # 21:07 0- 11 Merge remote-tracking branch 'linaro/apm_linux_v3.16-rc1' into mustang/vgic-active-unqueue git bisect good c9d26423e56ce1ab4d786f92aebecf859d419293 # 21:16 60+ 60 Merge tag 'pm+acpi-3.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm git bisect good 7bef919141fc53b780070a0aec3ddd893eeece8f # 21:27 60+ 60 Add linux-next specific files for 20140815 This script may reproduce the error. ---------------------------------------------------------------------------- #!/bin/bash kernel=$1 kvm=( qemu-system-x86_64 -cpu kvm64 -enable-kvm -kernel $kernel -m 320 -smp 2 -net nic,vlan=1,model=e1000 -net user,vlan=1 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -serial stdio -display none -monitor null ) append=( hung_task_panic=1 earlyprintk=ttyS0,115200 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=10 softlockup_panic=1 nmi_watchdog=panic load_ramdisk=2 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal root=/dev/ram0 rw drbd.minor_count=8 ) "${kvm[@]}" --append "${append[*]}" ---------------------------------------------------------------------------- Thanks, Fengguang