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Prarit Bhargava 7180dddf7c intel_pstate: Fix overflow in busy_scaled due to long delay 
The kernel may delay interrupts for a long time which can result in timers
being delayed. If this occurs the intel_pstate driver will crash with a
divide by zero error:

divide error: 0000 [#1] SMP
Modules linked in: btrfs zlib_deflate raid6_pq xor msdos ext4 mbcache jbd2 binfmt_misc arc4 md4 nls_utf8 cifs dns_resolver tcp_lp bnep bluetooth rfkill fuse dm_service_time iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_ftp ip6t_rpfilter ip6t_REJECT ipt_REJECT xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw iptable_filter ip_tables intel_powerclamp coretemp vfat fat kvm_intel iTCO_wdt iTCO_vendor_support ipmi_devintf sr_mod kvm crct10dif_pclmul
 crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel cdc_ether lrw usbnet cdrom mii gf128mul glue_helper ablk_helper cryptd lpc_ich mfd_core pcspkr sb_edac edac_core ipmi_si ipmi_msghandler ioatdma wmi shpchp acpi_pad nfsd auth_rpcgss nfs_acl lockd uinput dm_multipath sunrpc xfs libcrc32c usb_storage sd_mod crc_t10dif crct10dif_common ixgbe mgag200 syscopyarea sysfillrect sysimgblt mdio drm_kms_helper ttm igb drm ptp pps_core dca i2c_algo_bit megaraid_sas i2c_core dm_mirror dm_region_hash dm_log dm_mod
CPU: 113 PID: 0 Comm: swapper/113 Tainted: G        W   --------------   3.10.0-229.1.2.el7.x86_64 #1
Hardware name: IBM x3950 X6 -[3837AC2]-/00FN827, BIOS -[A8E112BUS-1.00]- 08/27/2014
task: ffff880fe8abe660 ti: ffff880fe8ae4000 task.ti: ffff880fe8ae4000
RIP: 0010:[<ffffffff814a9279>]  [<ffffffff814a9279>] intel_pstate_timer_func+0x179/0x3d0
RSP: 0018:ffff883fff4e3db8  EFLAGS: 00010206
RAX: 0000000027100000 RBX: ffff883fe6965100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000010 RDI: 000000002e53632d
RBP: ffff883fff4e3e20 R08: 000e6f69a5a125c0 R09: ffff883fe84ec001
R10: 0000000000000002 R11: 0000000000000005 R12: 00000000000049f5
R13: 0000000000271000 R14: 00000000000049f5 R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff883fff4e0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7668601000 CR3: 000000000190a000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
 ffff883fff4e3e58 ffffffff81099dc1 0000000000000086 0000000000000071
 ffff883fff4f3680 0000000000000071 fbdc8a965e33afee ffffffff810b69dd
 ffff883fe84ec000 ffff883fe6965108 0000000000000100 ffffffff814a9100
Call Trace:
 <IRQ>

 [<ffffffff81099dc1>] ? run_posix_cpu_timers+0x51/0x840
 [<ffffffff810b69dd>] ? trigger_load_balance+0x5d/0x200
 [<ffffffff814a9100>] ? pid_param_set+0x130/0x130
 [<ffffffff8107df56>] call_timer_fn+0x36/0x110
 [<ffffffff814a9100>] ? pid_param_set+0x130/0x130
 [<ffffffff8107fdcf>] run_timer_softirq+0x21f/0x320
 [<ffffffff81077b2f>] __do_softirq+0xef/0x280
 [<ffffffff816156dc>] call_softirq+0x1c/0x30
 [<ffffffff81015d95>] do_softirq+0x65/0xa0
 [<ffffffff81077ec5>] irq_exit+0x115/0x120
 [<ffffffff81616355>] smp_apic_timer_interrupt+0x45/0x60
 [<ffffffff81614a1d>] apic_timer_interrupt+0x6d/0x80
 <EOI>

 [<ffffffff814a9c32>] ? cpuidle_enter_state+0x52/0xc0
 [<ffffffff814a9c28>] ? cpuidle_enter_state+0x48/0xc0
 [<ffffffff814a9d65>] cpuidle_idle_call+0xc5/0x200
 [<ffffffff8101d14e>] arch_cpu_idle+0xe/0x30
 [<ffffffff810c67c1>] cpu_startup_entry+0xf1/0x290
 [<ffffffff8104228a>] start_secondary+0x1ba/0x230
Code: 42 0f 00 45 89 e6 48 01 c2 43 8d 44 6d 00 39 d0 73 26 49 c1 e5 08 89 d2 4d 63 f4 49 63 c5 48 c1 e2 08 48 c1 e0 08 48 63 ca 48 99 <48> f7 f9 48 98 4c 0f af f0 49 c1 ee 08 8b 43 78 c1 e0 08 44 29
RIP  [<ffffffff814a9279>] intel_pstate_timer_func+0x179/0x3d0
 RSP <ffff883fff4e3db8>

The kernel values for cpudata for CPU 113 were:

struct cpudata {
  cpu = 113,
  timer = {
    entry = {
      next = 0x0,
      prev = 0xdead000000200200
    },
    expires = 8357799745,
    base = 0xffff883fe84ec001,
    function = 0xffffffff814a9100 <intel_pstate_timer_func>,
    data = 18446612406765768960,
<snip>
    i_gain = 0,
    d_gain = 0,
    deadband = 0,
    last_err = 22489
  },
  last_sample_time = {
    tv64 = 4063132438017305
  },
  prev_aperf = 287326796397463,
  prev_mperf = 251427432090198,
  sample = {
    core_pct_busy = 23081,
    aperf = 2937407,
    mperf = 3257884,
    freq = 2524484,
    time = {
      tv64 = 4063149215234118
    }
  }
}

which results in the time between samples = last_sample_time - sample.time
= 4063149215234118 - 4063132438017305 = 16777216813 which is 16.777 seconds.

The duration between reads of the APERF and MPERF registers overflowed a s32
sized integer in intel_pstate_get_scaled_busy()'s call to div_fp().  The result
is that int_tofp(duration_us) == 0, and the kernel attempts to divide by 0.

While the kernel shouldn't be delaying for a long time, it can and does
happen and the intel_pstate driver should not panic in this situation.  This
patch changes the div_fp() function to use div64_s64() to allow for "long"
division.  This will avoid the overflow condition on long delays.

[v2]: use div64_s64() in div_fp()

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 		2015-06-16 22:52:45 +02:00
..
accessibility
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acpi ACPI / SBS: Enable battery manager when present 2015-04-29 00:04:29 +02:00
amba
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android
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ata powerpc updates for 4.1 2015-04-16 13:53:32 -05:00
atm
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auxdisplay
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base Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
bcma Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2015-04-17 15:50:54 -04:00
block rbd: end I/O the entire obj_request on error 2015-05-01 16:44:30 -07:00
bluetooth Bluetooth: btusb: Use proper data structures for Intel vendor events 2015-04-09 10:42:18 +03:00
bus ARM: SoC driver updates for v4.1 2015-04-22 09:18:17 -07:00
cdrom
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char Char/Misc driver patches for 4.1-rc1 2015-04-21 09:42:58 -07:00
clk ARM: SoC multiplatform code changes for v4.1 2015-04-22 09:20:15 -07:00
clocksource Initial ACPI support for arm64: 2015-04-24 08:23:45 -07:00
connector
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cpufreq intel_pstate: Fix overflow in busy_scaled due to long delay 2015-06-16 22:52:45 +02:00
cpuidle cpuidle: Run tick_broadcast_exit() with disabled interrupts 2015-04-29 15:19:21 +02:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2015-04-26 13:51:05 -07:00
dca
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devfreq
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dio
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dma dmaengine: increment privatecnt when using dma_get_any_slave_channel 2015-04-29 16:47:57 +05:30
dma-buf dma-buf: cleanup dma_buf_export() to make it easily extensible 2015-04-21 14:47:16 +05:30
edac
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eisa
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extcon Char/Misc driver patches for 4.1-rc1 2015-04-21 09:42:58 -07:00
firewire
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firmware ARM: SoC driver updates for v4.1 2015-04-22 09:18:17 -07:00
fmc
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gpio ARM: SoC cleanups for v4.1 2015-04-22 09:04:39 -07:00
gpu Merge tag 'drm-intel-fixes-2015-04-30' of git://anongit.freedesktop.org/drm-intel into drm-fixes 2015-05-04 08:56:47 +10:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2015-04-14 18:25:15 -07:00
hsi
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hv
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hwmon hwmon: (w83795) use find_closest_descending() in pwm_freq_to_reg() 2015-04-17 09:03:55 -04:00
hwspinlock
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hwtracing/coresight Char/Misc driver patches for 4.1-rc1 2015-04-21 09:42:58 -07:00
i2c Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2015-04-26 17:44:09 -07:00
ide ide: remove deprecated use of pci api 2015-04-17 15:32:07 -04:00
idle Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
iio Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2015-04-14 09:50:27 -07:00
infiniband Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
input platform/chrome: Updates for v4.1 2015-04-26 13:36:02 -07:00
iommu Merge git://git.infradead.org/intel-iommu 2015-04-26 17:47:46 -07:00
ipack
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irqchip Initial ACPI support for arm64: 2015-04-24 08:23:45 -07:00
isdn Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-04-15 09:00:47 -07:00
leds This is the bulk of GPIO changes for the v4.1 development 2015-04-18 08:22:10 -04:00
lguest Some virtio internal cleanups, a new virtio device "virtio input", and 2015-04-22 10:55:06 -07:00
macintosh
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mailbox
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mcb
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md dm: fix free_rq_clone() NULL pointer when requeueing unmapped request 2015-04-30 10:25:21 -04:00
media v4l: xilinx: fix for include file movement 2015-04-26 09:56:08 -07:00
memory ARM: SoC driver updates for v4.1 2015-04-22 09:18:17 -07:00
memstick memstick: mspro_block: add missing curly braces 2015-04-17 09:04:09 -04:00
message
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mfd platform/chrome: Updates for v4.1 2015-04-26 13:36:02 -07:00
misc Char/Misc driver patches for 4.1-rc1 2015-04-21 09:42:58 -07:00
mmc Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma 2015-04-24 09:49:37 -07:00
mtd Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
net net: fec: Fix RGMII-ID mode 2015-04-30 16:48:53 -04:00
nfc
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ntb
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nubus
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of Devicetree updates for 4.1: 2015-04-24 08:46:18 -07:00
oprofile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
parisc parisc: Eliminate sg_virt_addr() and private scatterlist.h 2015-04-21 22:02:43 +02:00
parport
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pci xen: features and fixes for 4.1-rc0 2015-04-16 14:01:03 -05:00
pcmcia ARM: SoC cleanups for v4.1 2015-04-22 09:04:39 -07:00
phy USB patches for 4.1-rc1 2015-04-13 17:07:21 -07:00
pinctrl pinctrl: fix allmodconfig noise 2015-04-15 10:02:42 +02:00
platform platform-drivers-x86 for 4.1 2015-04-26 13:44:46 -07:00
pnp Power management and ACPI updates for v4.1-rc1 2015-04-14 20:21:54 -07:00
power
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powercap powercap / RAPL: Add support for Intel Skylake processors 2015-04-15 23:06:16 +02:00
pps
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ps3
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ptp
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pwm pwm: Remove __init initializer for pwm_add_table() 2015-04-23 14:50:52 +02:00
rapidio
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ras
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regulator == Changes to existing drivers == 2015-04-14 17:29:55 -07:00
remoteproc
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reset
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rpmsg
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rtc drivers/rtc/rtc-at91rm9200.c: make IO endian agnostic 2015-04-17 09:04:12 -04:00
s390 s390/3215: free memory in error path 2015-04-23 16:55:50 +02:00
sbus drivers/sbus/char/envctrl.c: ignore orderly_poweroff return value 2015-04-15 16:35:23 -07:00
scsi 3w-9xxx: fix command completion race 2015-04-27 10:10:19 -07:00
sfi
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sh drivers: sh: Remove test for now unsupported sh7372 2015-04-27 13:08:14 +09:00
sn
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soc - fix unused variable warning for pmic-wrapper 2015-04-14 00:43:28 +02:00
spi Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma 2015-04-24 09:49:37 -07:00
spmi
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ssb Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2015-04-17 15:50:54 -04:00
staging Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2015-04-24 10:22:09 -07:00
tc
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thermal
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thunderbolt
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tty serial: 8250_pci: Add support for 16 port Exar boards 2015-04-28 20:22:31 +02:00
uio
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usb cdc-acm: prevent infinite loop when parsing CDC headers. 2015-04-28 12:53:16 +02:00
uwb
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vfio vfio-pci: Fix use after free 2015-04-08 08:11:51 -06:00
vhost Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2015-04-24 10:22:09 -07:00
video fbdev changes for v4.1 2015-04-20 15:16:25 -07:00
virt
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virtio virtio: drop virtio_device_is_legacy_only 2015-04-15 12:41:14 +09:30
vlynq
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vme
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w1
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watchdog Merge git://www.linux-watchdog.org/linux-watchdog 2015-04-22 11:22:55 -07:00
xen Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2015-04-24 10:22:09 -07:00
zorro
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Kconfig
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Makefile
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