linux-toradex.git/Documentation, branch v4.4.93

iio: adc: hx711: Add DT binding for avia,hx711

2017-10-08T08:14:17+00:00

[ Upstream commit ff1293f67734da68e23fecb6ecdae7112b8c43f9 ]

Add DT bindings for avia,hx711
Add vendor avia to vendor list

Signed-off-by: Andreas Klinger 
Acked-by: Rob Herring 
Signed-off-by: Jonathan Cameron 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

drm: bridge: add DT bindings for TI ths8135

2017-10-08T08:14:16+00:00

[ Upstream commit 2e644be30fcc08c736f66b60f4898d274d4873ab ]

THS8135 is a configurable video DAC. Add DT bindings for this chip.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Laurent Pinchart 
Acked-by: Rob Herring 
Signed-off-by: Archit Taneja 
Link: http://patchwork.freedesktop.org/patch/msgid/1481623759-12786-3-git-send-email-bgolaszewski@baylibre.com
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sysctl: enable strict writes

2017-07-05T12:37:16+00:00

commit 41662f5cc55335807d39404371cfcbb1909304c4 upstream.

SYSCTL_WRITES_WARN was added in commit f4aacea2f5d1 ("sysctl: allow for
strict write position handling"), and released in v3.16 in August of
2014.  Since then I can find only 1 instance of non-zero offset
writing[1], and it was fixed immediately in CRIU[2].  As such, it
appears safe to flip this to the strict state now.

[1] https://www.google.com/search?q="when%20file%20position%20was%20not%200"
[2] http://lists.openvz.org/pipermail/criu/2015-April/019819.html

Signed-off-by: Kees Cook 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Cc: Sumit Semwal 
Signed-off-by: Greg Kroah-Hartman

mm: larger stack guard gap, between vmas

2017-06-26T05:13:11+00:00

commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.

Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov 
Original-patch-by: Michal Hocko 
Signed-off-by: Hugh Dickins 
Acked-by: Michal Hocko 
Tested-by: Helge Deller  # parisc
Signed-off-by: Linus Torvalds 
[wt: backport to 4.11: adjust context]
[wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide]
[wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes]
Signed-off-by: Willy Tarreau 
[gkh: minor build fixes for 4.4]
Signed-off-by: Greg Kroah-Hartman

arm64: documentation: document tagged pointer stack constraints

2017-05-25T12:30:15+00:00

commit f0e421b1bf7af97f026e1bb8bfe4c5a7a8c08f42 upstream.

Some kernel features don't currently work if a task puts a non-zero
address tag in its stack pointer, frame pointer, or frame record entries
(FP, LR).

For example, with a tagged stack pointer, the kernel can't deliver
signals to the process, and the task is killed instead. As another
example, with a tagged frame pointer or frame records, perf fails to
generate call graphs or resolve symbols.

For now, just document these limitations, instead of finding and fixing
everything that doesn't work, as it's not known if anyone needs to use
tags in these places anyway.

In addition, as requested by Dave Martin, generalize the limitations
into a general kernel address tag policy, and refactor
tagged-pointers.txt to include it.

Fixes: d50240a5f6ce ("arm64: mm: permit use of tagged pointers at EL0")
Reviewed-by: Dave Martin 
Acked-by: Will Deacon 
Signed-off-by: Kristina Martsenko 
Signed-off-by: Catalin Marinas 
Signed-off-by: Greg Kroah-Hartman

clk: sunxi: Add apb0 gates for H3

2017-05-03T04:19:47+00:00

commit 6e17b4181603d183d20c73f4535529ddf2a2a020 upstream.

This patch adds support for APB0 in H3. It seems to be compatible with
earlier SOCs. apb0 gates controls R_ block peripherals (R_PIO, R_IR,
etc).

Since this gates behave just like any Allwinner clock gate, add a generic
compatible that can be reused if we don't have any clock to protect.

Signed-off-by: Krzysztof Adamski 
[Maxime: Removed the H3 compatible from the simple-gates driver, reworked
         the commit log a bit]
Signed-off-by: Maxime Ripard 
Cc: Julia Lawall 
Signed-off-by: Greg Kroah-Hartman

mnt: Add a per mount namespace limit on the number of mounts

2017-04-30T03:49:28+00:00

commit d29216842a85c7970c536108e093963f02714498 upstream.

CAI Qian  pointed out that the semantics
of shared subtrees make it possible to create an exponentially
increasing number of mounts in a mount namespace.

    mkdir /tmp/1 /tmp/2
    mount --make-rshared /
    for i in $(seq 1 20) ; do mount --bind /tmp/1 /tmp/2 ; done

Will create create 2^20 or 1048576 mounts, which is a practical problem
as some people have managed to hit this by accident.

As such CVE-2016-6213 was assigned.

Ian Kent  described the situation for autofs users
as follows:

> The number of mounts for direct mount maps is usually not very large because of
> the way they are implemented, large direct mount maps can have performance
> problems. There can be anywhere from a few (likely case a few hundred) to less
> than 10000, plus mounts that have been triggered and not yet expired.
>
> Indirect mounts have one autofs mount at the root plus the number of mounts that
> have been triggered and not yet expired.
>
> The number of autofs indirect map entries can range from a few to the common
> case of several thousand and in rare cases up to between 30000 and 50000. I've
> not heard of people with maps larger than 50000 entries.
>
> The larger the number of map entries the greater the possibility for a large
> number of active mounts so it's not hard to expect cases of a 1000 or somewhat
> more active mounts.

So I am setting the default number of mounts allowed per mount
namespace at 100,000.  This is more than enough for any use case I
know of, but small enough to quickly stop an exponential increase
in mounts.  Which should be perfect to catch misconfigurations and
malfunctioning programs.

For anyone who needs a higher limit this can be changed by writing
to the new /proc/sys/fs/mount-max sysctl.

Tested-by: CAI Qian 
Signed-off-by: "Eric W. Biederman" 
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

netlink: remove mmapped netlink support

2017-03-22T11:04:13+00:00

commit d1b4c689d4130bcfd3532680b64db562300716b6 upstream.

mmapped netlink has a number of unresolved issues:

- TX zerocopy support had to be disabled more than a year ago via
  commit 4682a0358639b29cf ("netlink: Always copy on mmap TX.")
  because the content of the mmapped area can change after netlink
  attribute validation but before message processing.

- RX support was implemented mainly to speed up nfqueue dumping packet
  payload to userspace.  However, since commit ae08ce0021087a5d812d2
  ("netfilter: nfnetlink_queue: zero copy support") we avoid one copy
  with the socket-based interface too (via the skb_zerocopy helper).

The other problem is that skbs attached to mmaped netlink socket
behave different from normal skbs:

- they don't have a shinfo area, so all functions that use skb_shinfo()
(e.g. skb_clone) cannot be used.

- reserving headroom prevents userspace from seeing the content as
it expects message to start at skb->head.
See for instance
commit aa3a022094fa ("netlink: not trim skb for mmaped socket when dump").

- skbs handed e.g. to netlink_ack must have non-NULL skb->sk, else we
crash because it needs the sk to check if a tx ring is attached.

Also not obvious, leads to non-intuitive bug fixes such as 7c7bdf359
("netfilter: nfnetlink: use original skbuff when acking batches").

mmaped netlink also didn't play nicely with the skb_zerocopy helper
used by nfqueue and openvswitch.  Daniel Borkmann fixed this via
commit 6bb0fef489f6 ("netlink, mmap: fix edge-case leakages in nf queue
zero-copy")' but at the cost of also needing to provide remaining
length to the allocation function.

nfqueue also has problems when used with mmaped rx netlink:
- mmaped netlink doesn't allow use of nfqueue batch verdict messages.
  Problem is that in the mmap case, the allocation time also determines
  the ordering in which the frame will be seen by userspace (A
  allocating before B means that A is located in earlier ring slot,
  but this also means that B might get a lower sequence number then A
  since seqno is decided later.  To fix this we would need to extend the
  spinlocked region to also cover the allocation and message setup which
  isn't desirable.
- nfqueue can now be configured to queue large (GSO) skbs to userspace.
  Queing GSO packets is faster than having to force a software segmentation
  in the kernel, so this is a desirable option.  However, with a mmap based
  ring one has to use 64kb per ring slot element, else mmap has to fall back
  to the socket path (NL_MMAP_STATUS_COPY) for all large packets.

To use the mmap interface, userspace not only has to probe for mmap netlink
support, it also has to implement a recv/socket receive path in order to
handle messages that exceed the size of an rx ring element.

Cc: Daniel Borkmann 
Cc: Ken-ichirou MATSUZAWA 
Cc: Pablo Neira Ayuso 
Cc: Patrick McHardy 
Cc: Thomas Graf 
Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller 
Cc: Shi Yuejie 
Signed-off-by: Greg Kroah-Hartman

samples: move mic/mpssd example code from Documentation

2017-03-12T05:37:23+00:00

commit 6bee835dd54e279f3d3ae2eca92a9c394b4fd028 upstream.

Move mic/mpssd examples to samples and remove it from Documentation
Makefile. Create a new Makefile to build mic/mpssd. It can be built
from top level directory or from mic/mpssd directory:

Run make -C samples/mic/mpssd or cd samples/mic/mpssd; make

Acked-by: Jonathan Corbet 
Signed-off-by: Shuah Khan 
[backported to 4.4-stable as this code is broken on newer versions of
 gcc and we don't want to break the build for a Documentation sample.
 - gregkh]
Signed-off-by: Greg Kroah-Hartman

x86/platform/goldfish: Prevent unconditional loading

2017-02-26T10:07:51+00:00

commit 47512cfd0d7a8bd6ab71d01cd89fca19eb2093eb upstream.

The goldfish platform code registers the platform device unconditionally
which causes havoc in several ways if the goldfish_pdev_bus driver is
enabled:

 - Access to the hardcoded physical memory region, which is either not
   available or contains stuff which is completely unrelated.

 - Prevents that the interrupt of the serial port can be requested

 - In case of a spurious interrupt it goes into a infinite loop in the
   interrupt handler of the pdev_bus driver (which needs to be fixed
   seperately).

Add a 'goldfish' command line option to make the registration opt-in when
the platform is compiled in.

I'm seriously grumpy about this engineering trainwreck, which has seven
SOBs from Intel developers for 50 lines of code. And none of them figured
out that this is broken. Impressive fail!

Fixes: ddd70cf93d78 ("goldfish: platform device for x86")
Reported-by: Gabriel C 
Signed-off-by: Thomas Gleixner 
Acked-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman