According to xHCI ch4.20 Scratchpad Buffers, the Scratchpad
Buffer needs to be zeroed.

	...
	The following operations take place to allocate
       	Scratchpad Buffers to the xHC:
	...
		b. Software clears the Scratchpad Buffer to '0'

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Intel Denverton microserver is Atom based and need the PME and CAS quirks
as well.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Don't access any members of a URB after giving it back.
URB might be freed by then already.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the new define for the maximum number of SuperSpeed ports instead of
a constant when allocating xHCI root hubs.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add define for the maximum number of ports on a SuperSpeed hub as per
USB 3.1 spec Table 10-5, and use it when verifying the retrieved hub
descriptor.

This specifically avoids benign attempts to update the DeviceRemovable
mask for non-existing ports (should we get that far).

Fixes: dbe79bbe ("USB 3.0 Hub Changes")
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add missing sanity check on the non-SuperSpeed hub-descriptor length in
order to avoid parsing and leaking two bytes of uninitialised slab data
through sysfs removable-attributes (or a compound-device debug
statement).

Note that we only make sure that the DeviceRemovable field is always
present (and specifically ignore the unused PortPwrCtrlMask field) in
order to continue support any hubs with non-compliant descriptors. As a
further safeguard, the descriptor buffer is also cleared.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>     # 2.6.12
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A SuperSpeed hub descriptor does not have any variable-length fields so
bail out when reading a short descriptor.

This avoids parsing and leaking two bytes of uninitialised slab data
through sysfs removable-attributes.

Fixes: dbe79bbe ("USB 3.0 Hub Changes")
Cc: stable <stable@vger.kernel.org>     # 2.6.39
Cc: John Youn <John.Youn@synopsys.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix up the root-hub descriptor to accommodate the variable-length
DeviceRemovable and PortPwrCtrlMask fields, while marking all ports as
removable (and leaving the reserved bit zero unset).

Also add a build-time constraint on VHCI_HC_PORTS which must never be
greater than USB_MAXCHILDREN (but this was only enforced through a
KConfig constant).

This specifically fixes the descriptor layout whenever VHCI_HC_PORTS is
greater than seven (default is 8).

Fixes: 04679b34 ("Staging: USB/IP: add client driver")
Cc: Takahiro Hirofuchi <hirofuchi@users.sourceforge.net>
Cc: Valentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Flag the first and only port as removable while also leaving the
remaining bits (including the reserved bit zero) unset in accordance
with the specifications:

	"Within a byte, if no port exists for a given location, the bit
	field representing the port characteristics shall be 0."

Also add a comment marking the legacy PortPwrCtrlMask field.

Fixes: 1cd8fd28 ("usb: gadget: dummy_hcd: add SuperSpeed support")
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Cc: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Even if this file is not yet included in any toctree, it is parsed by
Sphinx since it is named '.rst'. This patch fixes the following two
ERRORs from Sphinx build:

Documentation/usb/typec.rst:116: ERROR: Error in "kernel-doc" directive:
invalid option block.

.. kernel-doc:: drivers/usb/typec/typec.c
   :functions: typec_register_cable typec_unregister_cable typec_register_plug
   typec_unregister_plug

Documentation/usb/typec.rst:139: ERROR: Error in "kernel-doc" directive:
invalid option block.

.. kernel-doc:: drivers/usb/typec/typec.c
   :functions: typec_set_data_role typec_set_pwr_role typec_set_vconn_role
   typec_set_pwr_opmode
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Document that the new companion-device lookup helper takes a reference
to the companion device which needs to be dropped after use.
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure do drop the reference taken to the companion device during
resume.

Fixes: d4d75128 ("usb: host: ehci-platform: fix usb 1.1 device is not connected in system resume")
Cc: stable <stable@vger.kernel.org>     # 4.11
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

If multiple endpoints on a single device have pending IN URBs and one
endpoint times out due to NAKs (perfectly legal), select a different
endpoint URB to try.
The existing code only checked to see another device address has pending
URBs and ignores other IN endpoints on the current device address. This
leads to endpoints never getting serviced if one endpoint is using NAK as
a flow control method.

Fixes: 5d304358 ("usb: r8a66597-hcd: host controller driver for R8A6659")
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The timeout for BULK packets was 300ms which is a long time if other
endpoints or devices are waiting for their turn. Changing it to 50ms
greatly increased the overall performance for multi-endpoint devices.

Fixes: 5d304358 ("usb: r8a66597-hcd: host controller driver for R8A6659")
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Free memory allocated for address0_mutex if allocation of bandwidth_mutex
failed.

Fixes: feb26ac3 ("usb: core: hub: hub_port_init lock controller instead of bus")
Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Drop erroneous le16_to_cpu when returning the USB device speed which is
already in host byte order.

Found using sparse:

	warning: cast to restricted __le16

Fixes: 946b960d ("USB: add driver for iowarrior devices.")
Cc: stable <stable@vger.kernel.org>     # 2.6.21
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add missing endianness conversion when applying the Alea timeout quirk.

Found using sparse:

	warning: restricted __le16 degrades to integer

Fixes: e4a886e8 ("hwrng: chaoskey - Fix URB warning due to timeout on Alea")
Cc: stable <stable@vger.kernel.org>     # 4.8
Cc: Bob Ham <bob.ham@collabora.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

After commit d705ff38 (tty: vt, cleanup and document con_scroll), in
the coccinelle output, we can see:
drivers/usb/misc/sisusbvga/sisusb_con.c:852:8-9: WARNING: return of 0/1 in function 'sisusbcon_scroll_area' with return type bool

Return true instead of 1 in the function returning bool which was
intended to do in d705ff38 but omitted.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: d705ff38 (tty: vt, cleanup and document con_scroll)
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add missing endianness conversion when using the USB device-descriptor
idProduct field to apply a hardware quirk.

Fixes: 1ba47da5 ("uwb: add the i1480 DFU driver")
Cc: stable <stable@vger.kernel.org>     # 2.6.28
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

get_version_reply is not freed if function returns with success.

Fixes: 942a4873 ("usb: misc: legousbtower: Fix buffers on stack")
Reported-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Maksim Salau <maksim.salau@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Format specifier %p can leak kernel addresses while not valuing the
kptr_restrict system settings. When kptr_restrict is set to (1), kernel
pointers printed using the %pK format specifier will be replaced with
Zeros. Debugging Note : &pK prints only Zeros as address. If you need
actual address information, write 0 to kptr_restrict.

echo 0 > /proc/sys/kernel/kptr_restrict

[Found by poking around in a random vendor kernel tree, it would be nice
if someone would actually send these types of patches upstream - gkh]
Signed-off-by: Vamsi Krishna Samavedam <vskrishn@codeaurora.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The ene_usb6250 sub-driver in usb-storage does USB I/O to buffers on
the stack, which doesn't work with vmapped stacks.  This patch fixes
the problem by allocating a separate 512-byte buffer at probe time and
using it for all of the offending I/O operations.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Andreas Hartmann <andihartmann@01019freenet.de>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge tag 'fixes-for-v4.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-linus

Felipe writes:

usb: fixes for v4.12-rc2

- New device ID for Intel Canonlake CPUs
- fix for Isochronous performance regression on dwc3
- fix for out-of-bounds access on comp_desc on f_fs
- fix for lost events on dwc3 in case of spurious interrupts

Function devm_clk_get() returns an ERR_PTR when it fails. However, in
function kdwc3_probe(), its return value is not checked, which may
result in a bad memory access bug. This patch fixes the bug.
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

Companion descriptor is only used for SuperSpeed endpoints,
if the endpoints are HighSpeed or FullSpeed, the Companion
descriptor will not allocated, so we can only access it if
gadget is SuperSpeed.

I can reproduce this issue on Rockchip platform rk3368 SoC
which supports USB 2.0, and use functionfs for ADB. Kernel
build with CONFIG_KASAN=y and CONFIG_SLUB_DEBUG=y report
the following BUG:

==================================================================
BUG: KASAN: slab-out-of-bounds in ffs_func_set_alt+0x224/0x3a0 at addr ffffffc0601f6509
Read of size 1 by task swapper/0/0
============================================================================
BUG kmalloc-256 (Not tainted): kasan: bad access detected
----------------------------------------------------------------------------

Disabling lock debugging due to kernel taint
INFO: Allocated in ffs_func_bind+0x52c/0x99c age=1275 cpu=0 pid=1
alloc_debug_processing+0x128/0x17c
___slab_alloc.constprop.58+0x50c/0x610
__slab_alloc.isra.55.constprop.57+0x24/0x34
__kmalloc+0xe0/0x250
ffs_func_bind+0x52c/0x99c
usb_add_function+0xd8/0x1d4
configfs_composite_bind+0x48c/0x570
udc_bind_to_driver+0x6c/0x170
usb_udc_attach_driver+0xa4/0xd0
gadget_dev_desc_UDC_store+0xcc/0x118
configfs_write_file+0x1a0/0x1f8
__vfs_write+0x64/0x174
vfs_write+0xe4/0x200
SyS_write+0x68/0xc8
el0_svc_naked+0x24/0x28
INFO: Freed in inode_doinit_with_dentry+0x3f0/0x7c4 age=1275 cpu=7 pid=247
...
Call trace:
[<ffffff900808aab4>] dump_backtrace+0x0/0x230
[<ffffff900808acf8>] show_stack+0x14/0x1c
[<ffffff90084ad420>] dump_stack+0xa0/0xc8
[<ffffff90082157cc>] print_trailer+0x188/0x198
[<ffffff9008215948>] object_err+0x3c/0x4c
[<ffffff900821b5ac>] kasan_report+0x324/0x4dc
[<ffffff900821aa38>] __asan_load1+0x24/0x50
[<ffffff90089eb750>] ffs_func_set_alt+0x224/0x3a0
[<ffffff90089d3760>] composite_setup+0xdcc/0x1ac8
[<ffffff90089d7394>] android_setup+0x124/0x1a0
[<ffffff90089acd18>] _setup+0x54/0x74
[<ffffff90089b6b98>] handle_ep0+0x3288/0x4390
[<ffffff90089b9b44>] dwc_otg_pcd_handle_out_ep_intr+0x14dc/0x2ae4
[<ffffff90089be85c>] dwc_otg_pcd_handle_intr+0x1ec/0x298
[<ffffff90089ad680>] dwc_otg_pcd_irq+0x10/0x20
[<ffffff9008116328>] handle_irq_event_percpu+0x124/0x3ac
[<ffffff9008116610>] handle_irq_event+0x60/0xa0
[<ffffff900811af30>] handle_fasteoi_irq+0x10c/0x1d4
[<ffffff9008115568>] generic_handle_irq+0x30/0x40
[<ffffff90081159b4>] __handle_domain_irq+0xac/0xdc
[<ffffff9008080e9c>] gic_handle_irq+0x64/0xa4
...
Memory state around the buggy address:
  ffffffc0601f6400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffffffc0601f6480: 00 00 00 00 00 00 00 00 00 00 06 fc fc fc fc fc
 >ffffffc0601f6500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                       ^
  ffffffc0601f6580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffffffc0601f6600: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
==================================================================
Signed-off-by: William Wu <william.wu@rock-chips.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

Check for bad pointer that may result because of kthread_create failure.
This check is needed since the gserial setup callback function
(gs_console_setup()) is only freeing the info->con_buf in case of
kthread_create failure which will result into bad info->console_thread
pointer.
Without checking info->console_thread pointer validity in the
gserial_console_exit() function, before calling kthread_stop(), the
rmmod will generate Kernel Oops.
Signed-off-by: Bogdan Mirea <Bogdan-Stefan_mirea@mentor.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

The dwc3 driver can overwite its previous events if its top-half IRQ
handler (TH) gets invoked again before processing the events in the
cache. We see this as a hang in the file transfer and the host will
attempt to reset the device. TH gets the event count and deasserts the
interrupt line by writing DWC3_GEVNTSIZ_INTMASK to DWC3_GEVNTSIZ. If
there's a new event coming between reading the event count and interrupt
deassertion, dwc3 will lose previous pending events. More generally, we
will see 0 event count, which should not affect anything.

This shouldn't be possible in the current dwc3 implementation. However,
through testing and reading the PCIe trace, the TH occasionally still
gets invoked one more time after HW interrupt deassertion. (With PCIe
legacy interrupts, TH is called repeatedly as long as the interrupt line
is asserted). We suspect that there is a small detection delay in the
SW.

To avoid this issue, Check DWC3_EVENT_PENDING flag to determine if the
events are processed in the bottom-half IRQ handler. If not, return
IRQ_HANDLED and don't process new event.

Cc: stable@vger.kernel.org
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

Commit 08a36b54 ("usb: dwc3: gadget: simplify __dwc3_gadget_ep_queue()")
caused a small change in the way ISO transfer is handled in the case
when XferInProgress event happens on Isoc EP with an active transfer.
This caused a performance degradation of 50%. e.g. using g_webcam on DUT
and luvcview on host the video frame rate dropped from 16fps to 8fps
@high-speed.

Make the ISO transfer handling equivalent to that prior to that commit
to get back the original ISO performance numbers.

Fixes: 08a36b54 ("usb: dwc3: gadget: simplify __dwc3_gadget_ep_queue()")
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

Intel Cannonlake PCH has the same DWC3 than Intel
Sunrisepoint. Add the new IDs to the supported devices.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

Pull some more input subsystem updates from Dmitry Torokhov:
 "An updated xpad driver with a few more recognized device IDs, and a
  new psxpad-spi driver, allowing connecting Playstation 1 and 2 joypads
  via SPI bus"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: cros_ec_keyb - remove extraneous 'const'
  Input: add support for PlayStation 1/2 joypads connected via SPI
  Input: xpad - add USB IDs for Mad Catz Brawlstick and Razer Sabertooth
  Input: xpad - sync supported devices with xboxdrv
  Input: xpad - sort supported devices by USB ID

Pull UBI/UBIFS updates from Richard Weinberger:

 - new config option CONFIG_UBIFS_FS_SECURITY

 - minor improvements

 - random fixes

* tag 'upstream-4.12-rc1' of git://git.infradead.org/linux-ubifs:
  ubi: Add debugfs file for tracking PEB state
  ubifs: Fix a typo in comment of ioctl2ubifs & ubifs2ioctl
  ubifs: Remove unnecessary assignment
  ubifs: Fix cut and paste error on sb type comparisons
  ubi: fastmap: Fix slab corruption
  ubifs: Add CONFIG_UBIFS_FS_SECURITY to disable/enable security labels
  ubi: Make mtd parameter readable
  ubi: Fix section mismatch

Pull UML fixes from Richard Weinberger:
 "No new stuff, just fixes"

* 'for-linus-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Add missing NR_CPUS include
  um: Fix to call read_initrd after init_bootmem
  um: Include kbuild.h instead of duplicating its macros
  um: Fix PTRACE_POKEUSER on x86_64
  um: Set number of CPUs
  um: Fix _print_addr()

Merge misc fixes from Andrew Morton:
 "15 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm, docs: update memory.stat description with workingset* entries
  mm: vmscan: scan until it finds eligible pages
  mm, thp: copying user pages must schedule on collapse
  dax: fix PMD data corruption when fault races with write
  dax: fix data corruption when fault races with write
  ext4: return to starting transaction in ext4_dax_huge_fault()
  mm: fix data corruption due to stale mmap reads
  dax: prevent invalidation of mapped DAX entries
  Tigran has moved
  mm, vmalloc: fix vmalloc users tracking properly
  mm/khugepaged: add missed tracepoint for collapse_huge_page_swapin
  gcov: support GCC 7.1
  mm, vmstat: Remove spurious WARN() during zoneinfo print
  time: delete current_fs_time()
  hwpoison, memcg: forcibly uncharge LRU pages

Commit 4b4cea91691d ("mm: vmscan: fix IO/refault regression in cache
workingset transition") introduced three new entries in memory stat
file:

 - workingset_refault
 - workingset_activate
 - workingset_nodereclaim

This commit adds a corresponding description to the cgroup v2 docs.

Link: http://lkml.kernel.org/r/1494530293-31236-1-git-send-email-guro@fb.comSigned-off-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Although there are a ton of free swap and anonymous LRU page in elgible
zones, OOM happened.

  balloon invoked oom-killer: gfp_mask=0x17080c0(GFP_KERNEL_ACCOUNT|__GFP_ZERO|__GFP_NOTRACK), nodemask=(null),  order=0, oom_score_adj=0
  CPU: 7 PID: 1138 Comm: balloon Not tainted 4.11.0-rc6-mm1-zram-00289-ge228d67e9677-dirty #17
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
  Call Trace:
   oom_kill_process+0x21d/0x3f0
   out_of_memory+0xd8/0x390
   __alloc_pages_slowpath+0xbc1/0xc50
   __alloc_pages_nodemask+0x1a5/0x1c0
   pte_alloc_one+0x20/0x50
   __pte_alloc+0x1e/0x110
   __handle_mm_fault+0x919/0x960
   handle_mm_fault+0x77/0x120
   __do_page_fault+0x27a/0x550
   trace_do_page_fault+0x43/0x150
   do_async_page_fault+0x2c/0x90
   async_page_fault+0x28/0x30
  Mem-Info:
  active_anon:424716 inactive_anon:65314 isolated_anon:0
   active_file:52 inactive_file:46 isolated_file:0
   unevictable:0 dirty:27 writeback:0 unstable:0
   slab_reclaimable:3967 slab_unreclaimable:4125
   mapped:133 shmem:43 pagetables:1674 bounce:0
   free:4637 free_pcp:225 free_cma:0
  Node 0 active_anon:1698864kB inactive_anon:261256kB active_file:208kB inactive_file:184kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:532kB dirty:108kB writeback:0kB shmem:172kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
  DMA free:7316kB min:32kB low:44kB high:56kB active_anon:8064kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB slab_reclaimable:464kB slab_unreclaimable:40kB kernel_stack:0kB pagetables:24kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
  lowmem_reserve[]: 0 992 992 1952
  DMA32 free:9088kB min:2048kB low:3064kB high:4080kB active_anon:952176kB inactive_anon:0kB active_file:36kB inactive_file:0kB unevictable:0kB writepending:88kB present:1032192kB managed:1019388kB mlocked:0kB slab_reclaimable:13532kB slab_unreclaimable:16460kB kernel_stack:3552kB pagetables:6672kB bounce:0kB free_pcp:56kB local_pcp:24kB free_cma:0kB
  lowmem_reserve[]: 0 0 0 959
  Movable free:3644kB min:1980kB low:2960kB high:3940kB active_anon:738560kB inactive_anon:261340kB active_file:188kB inactive_file:640kB unevictable:0kB writepending:20kB present:1048444kB managed:1010816kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:832kB local_pcp:60kB free_cma:0kB
  lowmem_reserve[]: 0 0 0 0
  DMA: 1*4kB (E) 0*8kB 18*16kB (E) 10*32kB (E) 10*64kB (E) 9*128kB (ME) 8*256kB (E) 2*512kB (E) 2*1024kB (E) 0*2048kB 0*4096kB = 7524kB
  DMA32: 417*4kB (UMEH) 181*8kB (UMEH) 68*16kB (UMEH) 48*32kB (UMEH) 14*64kB (MH) 3*128kB (M) 1*256kB (H) 1*512kB (M) 2*1024kB (M) 0*2048kB 0*4096kB = 9836kB
  Movable: 1*4kB (M) 1*8kB (M) 1*16kB (M) 1*32kB (M) 0*64kB 1*128kB (M) 2*256kB (M) 4*512kB (M) 1*1024kB (M) 0*2048kB 0*4096kB = 3772kB
  378 total pagecache pages
  17 pages in swap cache
  Swap cache stats: add 17325, delete 17302, find 0/27
  Free swap  = 978940kB
  Total swap = 1048572kB
  524157 pages RAM
  0 pages HighMem/MovableOnly
  12629 pages reserved
  0 pages cma reserved
  0 pages hwpoisoned
  [ pid ]   uid  tgid total_vm      rss nr_ptes nr_pmds swapents oom_score_adj name
  [  433]     0   433     4904        5      14       3       82             0 upstart-udev-br
  [  438]     0   438    12371        5      27       3      191         -1000 systemd-udevd

With investigation, skipping page of isolate_lru_pages makes reclaim
void because it returns zero nr_taken easily so LRU shrinking is
effectively nothing and just increases priority aggressively.  Finally,
OOM happens.

The problem is that get_scan_count determines nr_to_scan with eligible
zones so although priority drops to zero, it couldn't reclaim any pages
if the LRU contains mostly ineligible pages.

get_scan_count:

        size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx);
	size = size >> sc->priority;

Assumes sc->priority is 0 and LRU list is as follows.

	N-N-N-N-H-H-H-H-H-H-H-H-H-H-H-H-H-H-H-H

(Ie, small eligible pages are in the head of LRU but others are
 almost ineligible pages)

In that case, size becomes 4 so VM want to scan 4 pages but 4 pages from
tail of the LRU are not eligible pages.  If get_scan_count counts
skipped pages, it doesn't reclaim any pages remained after scanning 4
pages so it ends up OOM happening.

This patch makes isolate_lru_pages try to scan pages until it encounters
eligible zones's pages.

[akpm@linux-foundation.org: clean up mind-bending `for' statement.  Tweak comment text]
Fixes: 3db65812 ("Revert "mm, vmscan: account for skipped pages as a partial scan"")
Link: http://lkml.kernel.org/r/1494457232-27401-1-git-send-email-minchan@kernel.orgSigned-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We have encountered need_resched warnings in __collapse_huge_page_copy()
while doing {clear,copy}_user_highpage() over HPAGE_PMD_NR source pages.

mm->mmap_sem is held for write, but the iteration is well bounded.

Reschedule as needed.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705101426380.109808@chino.kir.corp.google.comSigned-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is based on a patch from Jan Kara that fixed the equivalent race in
the DAX PTE fault path.

Currently DAX PMD read fault can race with write(2) in the following
way:

CPU1 - write(2)                 CPU2 - read fault
                                dax_iomap_pmd_fault()
                                  ->iomap_begin() - sees hole

dax_iomap_rw()
  iomap_apply()
    ->iomap_begin - allocates blocks
    dax_iomap_actor()
      invalidate_inode_pages2_range()
        - there's nothing to invalidate

                                  grab_mapping_entry()
				  - we add huge zero page to the radix tree
				    and map it to page tables

The result is that hole page is mapped into page tables (and thus zeros
are seen in mmap) while file has data written in that place.

Fix the problem by locking exception entry before mapping blocks for the
fault.  That way we are sure invalidate_inode_pages2_range() call for
racing write will either block on entry lock waiting for the fault to
finish (and unmap stale page tables after that) or read fault will see
already allocated blocks by write(2).

Fixes: 9f141d6e ("dax: Call ->iomap_begin without entry lock during dax fault")
Link: http://lkml.kernel.org/r/20170510172700.18991-1-ross.zwisler@linux.intel.comSigned-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently DAX read fault can race with write(2) in the following way:

CPU1 - write(2)			CPU2 - read fault
				dax_iomap_pte_fault()
				  ->iomap_begin() - sees hole
dax_iomap_rw()
  iomap_apply()
    ->iomap_begin - allocates blocks
    dax_iomap_actor()
      invalidate_inode_pages2_range()
        - there's nothing to invalidate
				  grab_mapping_entry()
				  - we add zero page in the radix tree
				    and map it to page tables

The result is that hole page is mapped into page tables (and thus zeros
are seen in mmap) while file has data written in that place.

Fix the problem by locking exception entry before mapping blocks for the
fault.  That way we are sure invalidate_inode_pages2_range() call for
racing write will either block on entry lock waiting for the fault to
finish (and unmap stale page tables after that) or read fault will see
already allocated blocks by write(2).

Fixes: 9f141d6e
Link: http://lkml.kernel.org/r/20170510085419.27601-5-jack@suse.czSigned-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

DAX will return to locking exceptional entry before mapping blocks for a
page fault to fix possible races with concurrent writes.  To avoid lock
inversion between exceptional entry lock and transaction start, start
the transaction already in ext4_dax_huge_fault().

Fixes: 9f141d6e
Link: http://lkml.kernel.org/r/20170510085419.27601-4-jack@suse.czSigned-off-by: Jan Kara <jack@suse.cz>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>