Measure latency does by itself contribute to an increased latency, thus we
should avoid it when it isn't needed.

By merging the latency measurements for the ->save_state() and the
->stop() callbacks, we get one measurement instead of two and we get one
value to store instead of two. Let's also apply the likewise change for
the ->start() and ->restore_state() callbacks.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Measure latency does by itself contribute to an increased latency, thus we
should avoid it when it isn't needed.

Genpd measures latencies in the system PM phase for the ->start|stop()
callbacks and is thus affecting the system PM suspend/resume time.
Moreover these latencies are validated only at runtime PM suspend/resume.

To this reasoning, let's decide to leave these measurements out of the
system PM phase. There should be plenty of occasions during runtime PM to
perform these measurements anyway.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit ba2bbfbf (PM / Domains: Remove intermediate states from the
power off sequence) changed the power off sequence in genpd. That also
required some updates regarding the validation of latency constraints in
the genpd governor. Unfortunate that wasn't covered, so let's fix this.

From a runtime PM and latency point of view, we need to consider the worst
case scenario while validating latency constraints. That's typically when
a call to pm_runtime_get_sync() needs to wait for a ongoing runtime
suspend operation to be carried out, as it then also needs to wait for the
device to be runtime resumed again.

The above mentioned commit made the genpd governor's ->stop_ok() callback
responsible of validating genpd's device's runtime suspend/resume latency.
In other words, the constraint needs to be validated towards the relevant
latencies present in genpd's ->runtime_suspend|resume() callbacks.

Earlier, that included latencies from the ->stop|start() callbacks, but as
->save|restore_state() are now also being invoked from genpd's
->runtime_suspend|resume() and to comply with the worst case scenario,
let's take also those latencies into account.

Fixes: ba2bbfbf (PM / Domains: Remove intermediate states from the power off sequence)
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This is another step to get consistent names of functions in genpd. Let's
rename the internal *pm_genpd_poweron|poweroff() into
*genpd_poweron|poweroff().
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Once genpd could be configured to be built with CONFIG_PM_RUNTIME unset
(nowadays CONFIG_PM), the pm_genpd_poweron() API served a purpose, since
it allowed users to power on a PM domain.

As such configuration no longer is supported, users shall solely rely on
using some of the runtime PM APIs to power on a PM domain.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

As the last user of the pm_genpd_poweroff_unused() API has moved into
relying on genpd to deal with this internally from a late_initcall, let's
remove the API.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Genpd tries from a late_initcall to disable unused PM domains, which makes
it unnecessary to also manage this from any earlier phase when for example
initializing a genpd.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit ba2bbfbf ("PM / Domains: Remove intermediate states..") changed
the power off sequence (pm_genpd_poweroff()), which from locking point of
view means the genpd mutex is held throughout the sequence.

The above change means the in_progress counter can't be updated while
pm_genpd_poweroff() is executing, which allows us to remove the counter.

Instead we inform pm_genpd_poweroff() via a bool parameter, to indicate
whether we call it from the scheduled work or from the ->runtime_suspend()
callback, since that all that matters.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull scheduler fix from Thomas Gleixner:
 "Fix a long standing state race in finish_task_switch()"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Fix TASK_DEAD race in finish_task_switch()

Pull perf fix from Thomas Glexiner:
 "Fix build breakage on powerpc in perf tools"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Fix build break on powerpc due to sample_reg_masks

Pull maintainer email update from Thomas Gleixner:
 "Change Matt Fleming's email address in the maintainers file"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Change Matt Fleming's email address

Pull irq fixes from Thomas Gleixner:
 "Three trivial commits:

   - Fix a kerneldoc regression

   - Export handle_bad_irq to unbreak a driver in next

   - Add an accessor for the of_node field so refactoring in next does
     not depend on merge ordering"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqdomain: Add an accessor for the of_node field
  genirq: Fix handle_bad_irq kerneldoc comment
  genirq: Export handle_bad_irq

Pull SCSI fixes from James Bottomley:
 "This is a set of three bug fixes, two of which are regressions from
  recent updates (the 3ware one from 4.1 and the device handler fixes
  from 4.2)"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  3w-9xxx: don't unmap bounce buffered commands
  scsi_dh: Use the correct module name when loading device handler
  libiscsi: Fix iscsi_check_transport_timeouts possible infinite loop

Pull md bugfix from Neil Brown:
 "One bug fix for raid1/raid10.

  Very careless bug earler in 4.3-rc, now fixed :-)"

* tag 'md/4.3-rc4-fix' of git://neil.brown.name/md:
  crash in md-raid1 and md-raid10 due to incorrect list manipulation

My Intel email address will soon expire. Replace it with my
personal address so people still know where to send patches.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1444494136-10333-1-git-send-email-matt@codeblueprint.co.ukSigned-off-by: Ingo Molnar <mingo@kernel.org>

Pull USB fixes from Greg KH:
 "Here are some small USB and PHY fixes and quirk updates for 4.3-rc5.

  Nothing major here, full details in the shortlog, and all of these
  have been in linux-next for a while"

* tag 'usb-4.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: Add device quirk for Logitech PTZ cameras
  USB: chaoskey read offset bug
  USB: Add reset-resume quirk for two Plantronics usb headphones.
  usb: renesas_usbhs: Add support for R-Car H3
  usb: renesas_usbhs: fix build warning if 64-bit architecture
  usb: gadget: bdc: fix memory leak
  phy: berlin-sata: Fix module autoload for OF platform driver
  phy: rockchip-usb: power down phy when rockchip phy probe
  phy: qcom-ufs: fix build error when the component is built as a module

Pull tty/serial driver fixes from Greg KH:
 "Here are a few bug fixes for the tty core that resolve reported
  issues, and some serial driver fixes as well (including the
  much-reported imx driver problem)

  All of these have been in linux-next with no reported problems"

* tag 'tty-4.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  drivers/tty: require read access for controlling terminal
  serial: 8250: add uart_config entry for PORT_RT2880
  tty: fix data race on tty_buffer.commit
  tty: fix data race in tty_buffer_flush
  tty: fix data race in flush_to_ldisc
  tty: fix stall caused by missing memory barrier in drivers/tty/n_tty.c
  serial: atmel: fix error path of probe function
  tty: don't leak cdev in tty_cdev_add()
  Revert "serial: imx: remove unbalanced clk_prepare"

Pull staging fixes from Greg KH:
 "Here are two tiny staging tree fixes for 4.3-rc5.

  One fixes the broken speakup subsystem as reported by a user, and the
  other removes an entry in the MAINTAINERS file for a developer that
  doesn't want to be listed anymore"

* tag 'staging-4.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: speakup: fix speakup-r regression
  MAINTAINERS: Remove myself as nvec co-maintainer

Pull char/misc driver fixes from Greg KH:
 "Here are some small fixes for some misc drivers that resolve some
  reported issues.  All of these have been linux-next for a while"

* tag 'char-misc-4.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  mcb: Fix error handling in mcb_pci_probe()
  mei: hbm: fix error in state check logic
  nvmem: sunxi: Check for memory allocation failure
  nvmem: core: Fix memory leak in nvmem_cell_write
  nvmem: core: Handle shift bits in-place if cell->nbits is non-zero
  nvmem: core: fix the out-of-range leak in read/write()

Pull MIPS fixes from Ralf Baechle:

 - MIPS didn't define the new ioremap_uc.  Defined it as an alias for
   ioremap_uncached.

 - Replace workaround for MIPS16 build issue with a correct one.

* git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Define ioremap_uc
  MIPS: UAPI: Ignore __arch_swab{16,32,64} when using MIPS16
  Revert "MIPS: UAPI: Fix unrecognized opcode WSBH/DSBH/DSHD when using MIPS16."

Pull swiotlb fixlet from Konrad Rzeszutek Wilk:
 "Enable the SWIOTLB under 32-bit PAE kernels.

  Nowadays most distros enable this due to CONFIG_HYPERVISOR|XEN=y which
  select SWIOTLB.  But for those that are not interested in
  virtualization and wanting to use 32-bit PAE kernels and wanting to
  have working DMA operations - this configures it for them"

* 'stable/for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
  swiotlb: Enable it under x86 PAE

Leandro Awa writes:
 "After switching to version 4.1.6, our parallelized and distributed
  workflows now fail consistently with errors of the form:

  T34: ./regex.c:39:22: error: config.h: No such file or directory

  From our 'git bisect' testing, the following commit appears to be the
  possible cause of the behavior we've been seeing: commit 766c4cbf"

Al Viro says:
 "What happens is that 766c4cbf got the things subtly wrong.

  We used to treat d_is_negative() after lookup_fast() as "fall with
  ENOENT".  That was wrong - checking ->d_flags outside of ->d_seq
  protection is unreliable and failing with hard error on what should've
  fallen back to non-RCU pathname resolution is a bug.

  Unfortunately, we'd pulled the test too far up and ran afoul of
  another kind of staleness.  The dentry might have been absolutely
  stable from the RCU point of view (and we might be on UP, etc), but
  stale from the remote fs point of view.  If ->d_revalidate() returns
  "it's actually stale", dentry gets thrown away and the original code
  wouldn't even have looked at its ->d_flags.

  What we need is to check ->d_flags where 766c4cbf does (prior to
  ->d_seq validation) but only use the result in cases where we do not
  discard this dentry outright"
Reported-by: Leandro Awa <lawa@nvidia.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=104911
Fixes: 766c4cbf ("namei: d_is_negative() should be checked...")
Tested-by: Leandro Awa <lawa@nvidia.com>
Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull power management and ACPI fixes from Rafael Wysocki:
 "These are four fixes for bugs in the devfreq and cpufreq subsystems,
  including two regression fixes (one for a recent regression and one
  for a problem introduced in 4.2).

  Specifics:

   - Two fixes for cpufreq regressions, an acpi-cpufreq driver one
     introduced during the 4.2 cycle when we started to preserve cpufreq
     directories for offline CPUs and a general one introduced recently
     (Srinivas Pandruvada).

   - Two devfreq fixes, one for a double kfree() in an error code path
     and one for a confusing sysfs-related failure (Geliang Tang, Tobias
     Jakobi)"

* tag 'pm+acpi-4.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: prevent lockup on reading scaling_available_frequencies
  cpufreq: acpi_cpufreq: prevent crash on reading freqdomain_cpus
  PM / devfreq: fix double kfree
  PM / devfreq: Fix governor_store()

Pull strscpy powerpc fix from Chris Metcalf.

Fix powerpc big-endian build.

* 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/powerpc: provide zero_bytemask() for big-endian

Pull sound fixes from Takashi Iwai:
 "We see various small fixes, but nothing looks too scary, all are small
  gentle bug fixes:

   - Most of changes are for ASoC codecs: Realtek, SGTL5000, TAS2552,
     TLV320, WM8962

   - A couple of dwc and imx-ssi fixes

   - Usual oneliner HD-audio quirks

   - An old emux synth code fix"

* tag 'sound-4.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  MAINTAINERS: Remove wm97xx entry
  ASoC: tas2552: fix dBscale-min declaration
  ALSA: synth: Fix conflicting OSS device registration on AWE32
  ALSA: hda - Disable power_save_node for IDT 92HD73xx chips
  ALSA: hda - Apply SPDIF pin ctl to MacBookPro 12,1
  ALSA: hda: Add dock support for ThinkPad T550
  ASoC: dwc: fix dma stop transferring issue
  ASoC: dwc: correct irq clear method
  ASoC: tlv320aic3x: Prevent writing reserved registers on tlv320aic3104 CODECs
  ASoC: rt5645: Correct the naming and setting of ADC Boost Volume Control
  ASoC: sgtl5000: fix wrong register MIC_BIAS_VOLTAGE setup on probe
  ASoC: wm8962: balance pm_runtime_enable
  ASoC: imx-ssi: Fix DAI hardware signal inversions
  ASoC: sgtl5000: fix error message output for MicBias voltage
  ASoC: db1200: Fix DAI link format for db1300 and db1550

Pull clk fixes from Stephen Boyd:
 "A Samsung driver fix and a handful of TI driver fixes"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: ti: dflt: fix enable_reg validity check
  clk: ti: fix dual-registration of uart4_ick
  clk: ti: clk-7xx: Remove hardwired ABE clock configuration
  clk: samsung: fix cpu clock's flags checking

Pull MMC fixes from Ulf Hansson:
 "MMC host:
   - omap_hsmmc: Fix boot regressions for omap4430
   - omap_hsmmc: Fix legacy boot regression for omap3
   - sdhci-pxav3: Fix some clock issues for Armada 38x
   - sdhci-pxav3: Fix error handling at probe
   - sdhci-of-at91: Fix clock stabilization problem"

* tag 'mmc-v4.3-rc4' of git://git.linaro.org/people/ulf.hansson/mmc:
  mmc: sdhci-of-at91: use SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST quirk
  mmc: sdhci: add quirk SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST
  mmc: sdhci-pxav3: fix error handling of armada_38x_quirks
  mmc: sdhci-pxav3: disable clock inversion for HS MMC cards
  mmc: sdhci-pxav3: remove broken clock base quirk for Armada 38x sdhci driver
  mmc: host: omap_hsmmc: Fix MMC for omap3 legacy booting
  Revert "mmc: host: omap_hsmmc: use regulator_is_enabled to find pbias status"

Pull dm fixes from Mike Snitzer:
 "Three stable fixes:

   - DM core AB-BA deadlock fix in the device destruction path (vs
     device creation's DM table swap).

   - DM raid fix to properly round up the region_size to the next
     power-of-2.

   - DM cache fix for a NULL pointer seen while switching from the
     "cleaner" cache policy.

  Two fixes for regressions introduced during the 4.3 merge:

   - request-based DM error propagation regressed due to incorrect
     changes introduced when adding the bi_error field to bio.

   - DM snapshot fix to only support snapshots that overflow if the
     client (e.g. lvm2) is prepared to deal with the associated
     snapshot status interface change"

* tag 'dm-4.3-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm snapshot: add new persistent store option to support overflow
  dm cache: fix NULL pointer when switching from cleaner policy
  dm: fix request-based dm error reporting
  dm raid: fix round up of default region size
  dm: fix AB-BA deadlock in __dm_destroy()

Pull btrfs fixes from Chris Mason:
 "These are small and assorted.  Neil's is the oldest, I dropped the
  ball thinking he was going to send it in"

* 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: support NFSv2 export
  Btrfs: open_ctree: Fix possible memory leak
  Btrfs: fix deadlock when finalizing block group creation
  Btrfs: update fix for read corruption of compressed and shared extents
  Btrfs: send, fix corner case for reference overwrite detection

Pull nfsd bugfix from Bruce Fields:
 "Just one RDMA bugfix"

* tag 'nfsd-4.3-1' of git://linux-nfs.org/~bfields/linux:
  svcrdma: handle rdma read with a non-zero initial page offset

Pull ARM SoC fixes from Arnd Bergmann:
 "The fixes for this week include one small patch that was years in the
  making and that finally fixes using all eight CPUs on exynos542x.

  The rest are lots of minor changes for sunxi, imx, exynos and shmobile

   - fixing the minimum voltage for Allwinner A20
   - thermal boot issue on SMDK5250.
   - invalid clock used for FIMD IOMMU.
   - audio on Renesas r8a7790/r8a7791
   - invalid clock used for FIMD IOMMU
   - LEDs on exynos5422-odroidxu3-common
   - usb pin control for imx-rex
   - imx53: fix PMIC interrupt level
   - a Makefile typo"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: dts: Fix wrong clock binding for sysmmu_fimd1_1 on exynos5420
  ARM: dts: Fix bootup thermal issue on smdk5250
  ARM: shmobile: r8a7791 dtsi: Add CPG/MSTP Clock Domain for sound
  ARM: shmobile: r8a7790 dtsi: Add CPG/MSTP Clock Domain for sound
  arm-cci500: Don't enable PMU driver by default
  ARM: dts: fix usb pin control for imx-rex dts
  ARM: imx53: qsrb: fix PMIC interrupt level
  ARM: imx53: include IRQ dt-bindings header
  ARM: dts: add suspend opp to exynos4412
  ARM: dts: Fix LEDs on exynos5422-odroidxu3
  ARM: EXYNOS: reset Little cores when cpu is up
  ARM: dts: Fix Makefile target for sun4i-a10-itead-iteaduino-plus
  ARM: dts: sunxi: Raise minimum CPU voltage for sun7i-a20 to meet SoC specifications

Commit 76c44f6d introduced the possibly for "Overflow" to be reported
by the snapshot device's status.  Older userspace (e.g. lvm2) does not
handle the "Overflow" status response.

Fix this incompatibility by requiring newer userspace code, that can
cope with "Overflow", request the persistent store with overflow support
by using "PO" (Persistent with Overflow) for the snapshot store type.
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Fixes: 76c44f6d ("dm snapshot: don't invalidate on-disk image on snapshot write overflow")
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

* pm-devfreq:
  PM / devfreq: fix double kfree
  PM / devfreq: Fix governor_store()

* pm-cpufreq:
  cpufreq: prevent lockup on reading scaling_available_frequencies
  cpufreq: acpi_cpufreq: prevent crash on reading freqdomain_cpus

As we're about to remove the of_node field from the irqdomain
structure, introduce an accessor for it. Subsequent patches
will take care of the actual repainting.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1444402211-1141-1-git-send-email-marc.zyngier@arm.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

A recent cleanup removed the 'irq' parameter from many functions, but
left the documentation for this in place for at least one function.

This removes it.

Fixes: bd0b9ac4 ("genirq: Remove irq argument from irq flow handlers")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: kbuild-all@01.org
Cc: Austin Schuh <austin@peloton-tech.com>
Cc: Santosh Shilimkar <ssantosh@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/5400000.cD19rmgWjV@wuerfelSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

A cleanup of the omap gpio driver introduced a use of the
handle_bad_irq() function in a device driver that can be
a loadable module.

This broke the ARM allmodconfig build:

ERROR: "handle_bad_irq" [drivers/gpio/gpio-omap.ko] undefined!

This patch exports the handle_bad_irq symbol in order to
allow the use in modules.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Santosh Shilimkar <ssantosh@kernel.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Austin Schuh <austin@peloton-tech.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/5847725.4IBopItaOr@wuerfelSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

The cleaner policy doesn't make use of the per cache block hint space in
the metadata (unlike the other policies).  When switching from the
cleaner policy to mq or smq a NULL pointer crash (in dm_tm_new_block)
was observed.  The crash was caused by bugs in dm-cache-metadata.c
when trying to skip creation of the hint btree.

The minimal fix is to change hint size for the cleaner policy to 4 bytes
(only hint size supported).
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

The commit 55ce74d4 (md/raid1: ensure
device failure recorded before write request returns) is causing crash in
the LVM2 testsuite test shell/lvchange-raid.sh. For me the crash is 100%
reproducible.

The reason for the crash is that the newly added code in raid1d moves the
list from conf->bio_end_io_list to tmp, then tests if tmp is non-empty and
then incorrectly pops the bio from conf->bio_end_io_list (which is empty
because the list was alrady moved).

Raid-10 has a similar bug.

Kernel Fault: Code=15 regs=000000006ccb8640 (Addr=0000000100000000)
CPU: 3 PID: 1930 Comm: mdX_raid1 Not tainted 4.2.0-rc5-bisect+ #35
task: 000000006cc1f258 ti: 000000006ccb8000 task.ti: 000000006ccb8000

     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
PSW: 00001000000001001111111000001111 Not tainted
r00-03  000000ff0804fe0f 000000001059d000 000000001059f818 000000007f16be38
r04-07  000000001059d000 000000007f16be08 0000000000200200 0000000000000001
r08-11  000000006ccb8260 000000007b7934d0 0000000000000001 0000000000000000
r12-15  000000004056f320 0000000000000000 0000000000013dd0 0000000000000000
r16-19  00000000f0d00ae0 0000000000000000 0000000000000000 0000000000000001
r20-23  000000000800000f 0000000042200390 0000000000000000 0000000000000000
r24-27  0000000000000001 000000000800000f 000000007f16be08 000000001059d000
r28-31  0000000100000000 000000006ccb8560 000000006ccb8640 0000000000000000
sr00-03  0000000000249800 0000000000000000 0000000000000000 0000000000249800
sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

IASQ: 0000000000000000 0000000000000000 IAOQ: 000000001059f61c 000000001059f620
 IIR: 0f8010c6    ISR: 0000000000000000  IOR: 0000000100000000
 CPU:        3   CR30: 000000006ccb8000 CR31: 0000000000000000
 ORIG_R28: 000000001059d000
 IAOQ[0]: call_bio_endio+0x34/0x1a8 [raid1]
 IAOQ[1]: call_bio_endio+0x38/0x1a8 [raid1]
 RP(r2): raid_end_bio_io+0x88/0x168 [raid1]
Backtrace:
 [<000000001059f818>] raid_end_bio_io+0x88/0x168 [raid1]
 [<00000000105a4f64>] raid1d+0x144/0x1640 [raid1]
 [<000000004017fd5c>] kthread+0x144/0x160
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 55ce74d4 ("md/raid1: ensure device failure recorded before write request returns.")
Fixes: 95af587e ("md/raid10: ensure device failure recorded before write request returns.")
Signed-off-by: NeilBrown <neilb@suse.com>