Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754559AbbGCCk5 (ORCPT ); Thu, 2 Jul 2015 22:40:57 -0400 Received: from kirsty.vergenet.net ([202.4.237.240]:49252 "EHLO kirsty.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753444AbbGCCks (ORCPT ); Thu, 2 Jul 2015 22:40:48 -0400 Date: Fri, 3 Jul 2015 11:40:44 +0900 From: Simon Horman To: Thomas Gleixner Cc: Kevin Hilman , Tyler Baker , Borislav Petkov , Geert Uytterhoeven , Magnus Damm , linux-sh@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Possible regression due to "tick: broadcast: Prevent livelock from event handler" Message-ID: <20150703024044.GB24695@verge.net.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Organisation: Horms Solutions Ltd. User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8046 Lines: 166 Hi Thomas, I have observed what appears to be a regression while testing next-20150702 which seems to be caused by 2951d5c031a3 ("tick: broadcast: Prevent livelock from event handler"). The problem manifests on the emev2/kzm9d board as per the boot log below. The problem manifests when booting using the shmobile_defconfig, which uses multiplatform and enables all devices using DT. The problem does not appear to always manifest but anecdotally it seems to manifest more often of late (yes, I know that is vague). This problem was reported to me by Geert Uytterhoeven. Kevin Hillman has also reported problems reliably booting the emev2/kzm9d board. Please note that in order to boot 2951d5c031a3 on the emev2/kzm9d board using the shmobile_defconfig the following is required: 6b442bc81337 ("nohz: Fix !HIGH_RES_TIMERS hang"). Booting Linux on physical CPU 0x0 Linux version 4.1.0-next-20150702 (horms@ayumi.isobedori.kobe.vergenet.net) (gcc version 4.6.3 (GCC) ) #4556 SMP Fri Jul 3 11:31:38 JST 2015 CPU: ARMv7 Processor [411fc093] revision 3 (ARMv7), cr=10c5307d CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache Machine model: EMEV2 KZM9D Board debug: ignoring loglevel setting. Memory policy: Data cache writealloc On node 0 totalpages: 32768 free_area_init_node: node 0, pgdat c0817500, node_mem_map c7ef9000 Normal zone: 256 pages used for memmap Normal zone: 0 pages reserved Normal zone: 32768 pages, LIFO batch:7 PERCPU: Embedded 9 pages/cpu @c7ee0000 s13824 r0 d23040 u36864 pcpu-alloc: s13824 r0 d23040 u36864 alloc=9*4096 pcpu-alloc: [0] 0 [0] 1 Built 1 zonelists in Zone order, mobility grouping on. Total pages: 32512 Kernel command line: console=ttyS1,115200n81 ignore_loglevel root=/dev/nfs ip=dhcp PID hash table entries: 512 (order: -1, 2048 bytes) Dentry cache hash table entries: 16384 (order: 4, 65536 bytes) Inode-cache hash table entries: 8192 (order: 3, 32768 bytes) Memory: 121328K/131072K available (4888K kernel code, 283K rwdata, 1352K rodata, 1728K init, 204K bss, 9744K reserved, 0K cma-reserved, 0K highmem) Virtual kernel memory layout: vector : 0xffff0000 - 0xffff1000 ( 4 kB) fixmap : 0xffc00000 - 0xfff00000 (3072 kB) vmalloc : 0xc8800000 - 0xff000000 ( 872 MB) lowmem : 0xc0000000 - 0xc8000000 ( 128 MB) pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB) .text : 0xc0008000 - 0xc0621044 (6245 kB) .init : 0xc0622000 - 0xc07d2000 (1728 kB) .data : 0xc07d2000 - 0xc0818e40 ( 284 kB) .bss : 0xc081b000 - 0xc084e24c ( 205 kB) Hierarchical RCU implementation. Additional per-CPU info printed with stalls. Build-time adjustment of leaf fanout to 32. RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=2. RCU: Adjusting geometry for rcu_fanout_leaf=32, nr_cpu_ids=2 NR_IRQS:16 nr_irqs:16 16 clocksource_of_init: no matching clocksources found sched_clock: 32 bits at 100 Hz, resolution 10000000ns, wraps every 21474836475000000ns Console: colour dummy device 80x30 Calibrating delay loop (skipped) preset value.. 355.33 BogoMIPS (lpj=1776666) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 1024 (order: 0, 4096 bytes) Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes) CPU: Testing write buffer coherency: ok CPU0: thread -1, cpu 0, socket 0, mpidr 80000000 Setting up static identity map for 0x40009000 - 0x40009058 CPU1: thread -1, cpu 1, socket 0, mpidr 80000001 Brought up 2 CPUs SMP: Total of 2 processors activated (710.66 BogoMIPS). CPU: All CPU(s) started in SVC mode. devtmpfs: initialized VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 1 clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns pinctrl core: initialized pinctrl subsystem NET: Registered protocol family 16 DMA: preallocated 256 KiB pool for atomic coherent allocations sh-pfc e0140200.pfc: emev2_pfc support registered No ATAGs? hw-breakpoint: found 5 (+1 reserved) breakpoint and 1 watchpoint registers. hw-breakpoint: maximum watchpoint size is 4 bytes. vgaarb: loaded SCSI subsystem initialized libata version 3.00 loaded. usbcore: registered new interface driver usbfs usbcore: registered new interface driver hub usbcore: registered new device driver usb media: Linux media interface: v0.10 Linux video capture interface: v2.00 em_sti e0180000.timer: used for clock events em_sti e0180000.timer: used for oneshot clock events em_sti e0180000.timer: used as clock source clocksource: e0180000.timer: mask: 0xffffffffffff max_cycles: 0x1ef4687b1, max_idle_ns: 3697658158765000000 ns Advanced Linux Sound Architecture Driver Initialized. clocksource: e0180000.timer: mask: 0xffffffffffff max_cycles: 0x1ef4687b1, max_idle_ns: 112843571739654 ns clocksource: Switched to clocksource e0180000.timer NET: Registered protocol family 2 TCP established hash table entries: 1024 (order: 0, 4096 bytes) TCP bind hash table entries: 1024 (order: 1, 8192 bytes) TCP: Hash tables configured (established 1024 bind 1024) UDP hash table entries: 256 (order: 1, 8192 bytes) UDP-Lite hash table entries: 256 (order: 1, 8192 bytes) NET: Registered protocol family 1 RPC: Registered named UNIX socket transport module. RPC: Registered udp transport module. RPC: Registered tcp transport module. RPC: Registered tcp NFSv4.1 backchannel transport module. PCI: CLS 0 bytes, default 64 Clockevents: could not switch to one-shot mode: dummy_timer is not functional. Clockevents: could not switch to one-shot mode: dummy_timer is not functional. hw perfevents: Failed to parse /pmu/interrupt-affinity[0] hw perfevents: enabled with armv7_cortex_a9 PMU driver, 7 counters available futex hash table entries: 512 (order: 3, 32768 bytes) NFS: Registering the id_resolver key type Key type id_resolver registered Key type id_legacy registered nfs4filelayout_init: NFSv4 File Layout Driver Registering... nfs4flexfilelayout_init: NFSv4 Flexfile Layout Driver Registering... jitterentropy: Initialization failed with host not compliant with requirements: 2 Block layer SCSI generic (bsg) driver version 0.4 loaded (major 250) io scheduler noop registered io scheduler deadline registered io scheduler cfq registered (default) Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled e1020000.serial: ttyS0 at MMIO 0xe1020000 (irq = 19, base_baud = 796444) is a 16550A console [ttyS1] disabled e1030000.serial: ttyS1 at MMIO 0xe1030000 (irq = 20, base_baud = 7168000) is a 16550A console [ttyS1] enabled e1040000.serial: ttyS2 at MMIO 0xe1040000 (irq = 21, base_baud = 14336000) is a 16550A e1050000.serial: ttyS3 at MMIO 0xe1050000 (irq = 22, base_baud = 2389333) is a 16550A SuperH (H)SCI(F) driver initialized [drm] Initialized drm 1.1.0 20060810 libphy: smsc911x-mdio: probed smsc911x 20000000.ethernet eth0: attached PHY driver [SMSC LAN8700] (mii_bus:phy_addr=20000000.etherne:01, irq=-1) smsc911x 20000000.ethernet eth0: MAC Address: 00:01:9b:04:03:cf ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver ehci-pci: EHCI PCI platform driver ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver ohci-pci: OHCI PCI platform driver mousedev: PS/2 mouse device common for all mice i2c /dev entries driver usbcore: registered new interface driver usbhid usbhid: USB HID core driver NET: Registered protocol family 10 sit: IPv6 over IPv4 tunneling driver NET: Registered protocol family 17 Key type dns_resolver registered cpu cpu0: failed to get cpu0 clock: -2 cpufreq-dt: probe of cpufreq-dt failed with error -2 Registering SWP/SWPB emulation handler input: gpio_keys as /devices/platform/gpio_keys/input/input0 hctosys: unable to open rtc device (rtc0) The boot hangs here. The next line should be: smsc911x 20000000.ethernet eth0: SMSC911x/921x identified at 0xc8880000, IRQ: 33 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/