linux-uconsole/drivers
Viresh Kumar e4b133cc4b cpufreq: Fix NULL reference crash while accessing policy->governor_data
There is a race discovered by Juri, where we are able to:
- create and read a sysfs file before policy->governor_data is being set
  to a non NULL value.
  OR
- set policy->governor_data to NULL, and reading a file before being
  destroyed.

And so such a crash is reported:

Unable to handle kernel NULL pointer dereference at virtual address 0000000c
pgd = edfc8000
[0000000c] *pgd=bfc8c835
Internal error: Oops: 17 [#1] SMP ARM
Modules linked in:
CPU: 4 PID: 1730 Comm: cat Not tainted 4.5.0-rc1+ #463
Hardware name: ARM-Versatile Express
task: ee8e8480 ti: ee930000 task.ti: ee930000
PC is at show_ignore_nice_load_gov_pol+0x24/0x34
LR is at show+0x4c/0x60
pc : [<c058f1bc>]    lr : [<c058ae88>]    psr: a0070013
sp : ee931dd0  ip : ee931de0  fp : ee931ddc
r10: ee4bc290  r9 : 00001000  r8 : ef2cb000
r7 : ee4bc200  r6 : ef2cb000  r5 : c0af57b0  r4 : ee4bc2e0
r3 : 00000000  r2 : 00000000  r1 : c0928df4  r0 : ef2cb000
Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 10c5387d  Table: adfc806a  DAC: 00000051
Process cat (pid: 1730, stack limit = 0xee930210)
Stack: (0xee931dd0 to 0xee932000)
1dc0:                                     ee931dfc ee931de0 c058ae88 c058f1a4
1de0: edce3bc0 c07bfca4 edce3ac0 00001000 ee931e24 ee931e00 c01fcb90 c058ae48
1e00: 00000001 edce3bc0 00000000 00000001 ee931e50 ee8ff480 ee931e34 ee931e28
1e20: c01fb33c c01fcb0c ee931e8c ee931e38 c01a5210 c01fb314 ee931e9c ee931e48
1e40: 00000000 edce3bf0 befe4a00 ee931f78 00000000 00000000 000001e4 00000000
1e60: c00545a8 edce3ac0 00001000 00001000 befe4a00 ee931f78 00000000 00001000
1e80: ee931ed4 ee931e90 c01fbed8 c01a5038 ed085a58 00020000 00000000 00000000
1ea0: c0ad72e4 ee931f78 ee8ff488 ee8ff480 c077f3fc 00001000 befe4a00 ee931f78
1ec0: 00000000 00001000 ee931f44 ee931ed8 c017c328 c01fbdc4 00001000 00000000
1ee0: ee8ff480 00001000 ee931f44 ee931ef8 c017c65c c03deb10 ee931fac ee931f08
1f00: c0009270 c001f290 c0a8d968 ef2cb000 ef2cb000 ee8ff480 00000020 ee8ff480
1f20: ee8ff480 befe4a00 00001000 ee931f78 00000000 00000000 ee931f74 ee931f48
1f40: c017d1ec c017c2f8 c019c724 c019c684 ee8ff480 ee8ff480 00001000 befe4a00
1f60: 00000000 00000000 ee931fa4 ee931f78 c017d2a8 c017d160 00000000 00000000
1f80: 000a9f20 00001000 befe4a00 00000003 c000ffe4 ee930000 00000000 ee931fa8
1fa0: c000fe40 c017d264 000a9f20 00001000 00000003 befe4a00 00001000 00000000
Unable to handle kernel NULL pointer dereference at virtual address 0000000c
1fc0: 000a9f20 00001000 befe4a00 00000003 00000000 00000000 00000003 00000001
pgd = edfc4000
[0000000c] *pgd=bfcac835
1fe0: 00000000 befe49dc 000197f8 b6e35dfc 60070010 00000003 3065b49d 134ac2c9

[<c058f1bc>] (show_ignore_nice_load_gov_pol) from [<c058ae88>] (show+0x4c/0x60)
[<c058ae88>] (show) from [<c01fcb90>] (sysfs_kf_seq_show+0x90/0xfc)
[<c01fcb90>] (sysfs_kf_seq_show) from [<c01fb33c>] (kernfs_seq_show+0x34/0x38)
[<c01fb33c>] (kernfs_seq_show) from [<c01a5210>] (seq_read+0x1e4/0x4e4)
[<c01a5210>] (seq_read) from [<c01fbed8>] (kernfs_fop_read+0x120/0x1a0)
[<c01fbed8>] (kernfs_fop_read) from [<c017c328>] (__vfs_read+0x3c/0xe0)
[<c017c328>] (__vfs_read) from [<c017d1ec>] (vfs_read+0x98/0x104)
[<c017d1ec>] (vfs_read) from [<c017d2a8>] (SyS_read+0x50/0x90)
[<c017d2a8>] (SyS_read) from [<c000fe40>] (ret_fast_syscall+0x0/0x1c)
Code: e5903044 e1a00001 e3081df4 e34c1092 (e593300c)
---[ end trace 5994b9a5111f35ee ]---

Fix that by making sure, policy->governor_data is updated at the right
places only.

Cc: 4.2+ <stable@vger.kernel.org> # 4.2+
Reported-and-tested-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-01-27 23:13:53 +01:00
..
accessibility
acpi nfit: acpi_nfit_notify(): Do not leave device locked 2015-12-11 14:24:26 -08:00
amba
android
ata ata/sata_fsl.c: add ATA_FLAG_NO_LOG_PAGE to blacklist the controller for log page reads 2015-12-07 10:25:57 -05:00
atm
auxdisplay
base Merge branch 'pm-opp' into pm-cpufreq 2016-01-02 00:49:05 +01:00
bcma
block xen: bug fixes for 4.4-rc5 2015-12-18 12:24:52 -08:00
bluetooth Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-11-10 18:11:41 -08:00
bus Merge branch 'x15-audio-fixes' into omap-for-v4.4/fixes 2015-11-12 09:58:21 -08:00
cdrom
char ipmi: move timer init to before irq is setup 2015-12-09 13:13:06 -06:00
clk ARM: SoC fixes for 4.4-rc 2015-12-12 16:43:44 -08:00
clocksource clocksource: Mmio: remove artificial 32bit limitation 2015-12-10 19:37:18 +01:00
connector mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd 2015-11-06 17:50:42 -08:00
cpufreq cpufreq: Fix NULL reference crash while accessing policy->governor_data 2016-01-27 23:13:53 +01:00
cpuidle cpuidle: mvebu: disable the bind/unbind attributes and use builtin_platform_driver 2015-10-23 12:40:48 +02:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2015-12-05 10:46:44 -08:00
dca
devfreq
dio
dma dmaengine: at_xdmac: fix at_xdmac_prep_dma_memcpy() 2015-12-10 09:48:01 +05:30
dma-buf dma-buf/fence: add fence_wait_any_timeout function v2 2015-10-30 01:16:16 -04:00
edac asm-generic cleanups 2015-11-06 14:22:15 -08:00
eisa
extcon Merge branches 'ib-extcon-mfd-4.4', 'ib-mfd-i2c-v4.4', 'ib-mfd-power-4.4', 'ib-mfd-regmap-4.4' and 'ib-mfd-regulator-4.4' into ibs-for-mfd-merged 2015-10-26 14:48:22 +00:00
firewire IEEE 1394 subsystem patch: 2015-11-11 10:21:34 -08:00
firmware ARM: SoC driver updates for v4.4 2015-11-10 15:00:03 -08:00
fmc
fpga fpga manager: Fix firmware resource leak on error 2015-11-24 15:25:46 -08:00
gpio gpio: revert get() to non-errorprogating behaviour 2015-12-17 15:48:29 +01:00
gpu drm: Don't overwrite UNVERFIED mode status to OK 2015-12-15 11:00:10 +10:00
hid USB fixes for 4.4-rc5 2015-12-13 11:58:18 -08:00
hsi hsi: controllers:remove redundant code 2015-10-30 16:10:40 +01:00
hv drivers/hv: share Hyper-V SynIC constants with userspace 2015-11-04 16:24:33 +01:00
hwmon hwmon: (sht15) Select CONFIG_BITREVERSE 2015-12-18 08:19:52 -08:00
hwspinlock
hwtracing Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2015-11-13 20:04:17 -08:00
i2c i2c: rcar: disable runtime PM correctly in slave mode 2015-12-19 12:00:37 +01:00
ide mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM 2015-11-06 17:50:42 -08:00
idle
iio iio: adc: spmi-vadc: add missing of_node_put 2015-11-21 18:24:44 +00:00
infiniband IB/mlx5: Postpone remove_keys under knowledge of coming preemption 2015-12-08 16:55:31 -05:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2015-12-19 09:51:11 -08:00
iommu IOMMU Fixes for Linux v4.4-rc5 2015-12-18 12:38:35 -08:00
ipack
irqchip irqchip/versatile-fpga: Fix PCI IRQ mapping on Versatile PB 2015-12-01 22:50:16 +01:00
isdn ser_gigaset: remove unnecessary kfree() calls from release method 2015-12-15 13:24:21 -05:00
leds spi: Updates for v4.4 2015-11-05 13:15:12 -08:00
lguest
lightnvm lightnvm: do not compile in debugging by default 2015-12-07 09:14:20 -07:00
macintosh
mailbox mailbox: mailbox-test: avoid reading iomem twice 2015-11-04 14:03:04 +05:30
mcb mcb: Destroy IDA on module unload 2015-10-29 09:02:16 +09:00
md Fix remove_and_add_spares removes drive added as spare in slot_store 2015-12-18 15:19:16 +11:00
media media fixes for v4.4-rc6 2015-12-18 15:41:35 -08:00
memory ARM: SoC driver updates for v4.4 2015-11-10 15:00:03 -08:00
memstick
message SCSI queue for 4.4. 2015-11-12 07:06:18 -05:00
mfd asm-generic cleanups 2015-11-06 14:22:15 -08:00
misc cxl: Set endianess of kernel contexts 2015-12-08 16:57:01 +11:00
mmc mmc: remove bondage between REQ_META and reliable write 2015-11-09 14:04:52 +01:00
mtd doc: dt: mtd: partitions: add compatible property to "partitions" node 2015-12-08 17:10:20 -08:00
net xen: bug fixes for 4.4-rc5 2015-12-18 12:24:52 -08:00
nfc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-11-10 18:11:41 -08:00
ntb NTB: fix 32-bit compiler warning 2015-11-08 16:24:43 -05:00
nubus
nvdimm libnvdimm, pmem: fix size trim in pmem_direct_access() 2015-11-12 09:55:23 -08:00
nvme lightnvm: replace req queue with nvmdev for lld 2015-12-07 09:14:19 -07:00
nvmem
of of/irq: Export of_irq_find_parent again 2015-12-09 09:08:36 -06:00
oprofile
parisc parisc iommu: fix panic due to trying to allocate too large region 2015-12-12 16:07:25 +01:00
parport
pci PCI updates for v4.4: 2015-12-09 09:26:06 -08:00
pcmcia
perf arm64 updates for 4.4: 2015-11-04 14:47:13 -08:00
phy phy: core: Get a refcount to phy in devm_of_phy_get_by_index() 2015-12-07 18:44:02 +05:30
pinctrl pinctrl: bcm2835: Fix initial value for direction_output 2015-12-14 11:31:20 +01:00
platform platform/chrome: Branch for v4.4 2015-11-13 21:53:18 -08:00
pnp
power - New Device Support 2015-11-06 10:23:50 -08:00
powercap powercap / RAPL: fix BIOS lock check 2015-12-12 02:31:11 +01:00
pps
ps3
ptp
pwm pwm: Changes for v4.4-rc1 2015-11-11 09:16:10 -08:00
rapidio
ras
regulator spi: Updates for v4.4 2015-11-05 13:15:12 -08:00
remoteproc remoteproc: fix memory leak of remoteproc ida cache layers 2015-11-26 17:44:28 +02:00
reset
rpmsg
rtc rtc: da9063: fix access ordering error during RTC interrupt at system power on 2015-12-20 13:39:29 +01:00
s390 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2015-11-18 08:59:29 -08:00
sbus
scsi Merge remote-tracking branch 'mkp-scsi/4.4/scsi-fixes' into fixes 2015-12-17 07:32:08 -08:00
sfi
sh drivers: sh: Get rid of CONFIG_ARCH_SHMOBILE_MULTI 2015-11-17 02:12:46 +09:00
sn
soc Few Keystone fixes for 4.4-rcx 2015-11-25 23:48:12 +01:00
spi Merge remote-tracking branches 'spi/fix/dspi' and 'spi/fix/spidev' into spi-linus 2015-12-16 13:28:32 +00:00
spmi char/misc drivers for 4.4-rc1 2015-11-04 22:15:15 -08:00
ssb ssb: add Kconfig entry for compiling SoC related code 2015-10-28 21:05:21 +02:00
staging Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2015-12-17 11:20:13 -08:00
target target/stat: print full t10_wwn.model buffer 2015-11-28 21:23:13 -08:00
tc
thermal imx: thermal: use CPU temperature grade info for thresholds 2015-11-23 16:38:40 -08:00
thunderbolt
tty tty: Fix GPF in flush_to_ldisc() 2015-12-12 23:05:28 -08:00
uio
usb USB: fix invalid memory access in hub_activate() 2015-12-18 09:30:34 -08:00
uwb driver core update for 4.4-rc1 2015-11-04 21:50:37 -08:00
vfio Revert: "vfio: Include No-IOMMU mode" 2015-12-04 08:38:42 -07:00
vhost vhost: replace % with & on data path 2015-12-07 17:28:10 +02:00
video OMAPDSS: fix timings for VENC to match what omapdrm expects 2015-12-09 12:57:13 +02:00
virt
virtio virtio_ring: shadow available ring flags & index 2015-12-07 17:28:11 +02:00
vlynq
vme char/misc drivers for 4.4-rc1 2015-11-04 22:15:15 -08:00
w1 power supply and reset changes for the v4.4 series 2015-11-05 12:28:15 -08:00
watchdog watchdog: mtk_wdt: Use MODE_KEY when stopping the watchdog 2015-11-23 09:00:09 +01:00
xen xen: bug fixes for 4.4-rc5 2015-12-18 12:24:52 -08:00
zorro
Kconfig char/misc drivers for 4.4-rc1 2015-11-04 22:15:15 -08:00
Makefile null_blk: register as a LightNVM device 2015-11-16 15:22:28 -07:00