linux-stable.git/Documentation, branch v3.18.52

netlink: remove mmapped netlink support

2017-04-18T05:55:51+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

2017-04-18T05:55:51+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 3.18-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

Documentation: Remove ZBOOT MMC/SDHI utility and docs

2017-02-08T08:43:05+00:00

commit c6535e1e0361157ea073b57b626d0611b7c4c7a0 upstream.

Remove ZBOOT MMC/SDHI Documentation for sh7372 together
wit the vrl4 utility. Without sh7372 and Mackerel support
these files are no longer useful.

Signed-off-by: Magnus Damm 
Acked-by: Laurent Pinchart 
Acked-by: Geert Uytterhoeven 
Signed-off-by: Simon Horman 
[removes a build warning in 3.18, and as this chip never was made, it is
 safe to remove the documentation here.  The code was removed in 4.1.
 - gregkh]
Signed-off-by: Greg Kroah-Hartman

MODULE_DEVICE_TABLE: fix some callsites

2017-02-08T08:43:03+00:00

commit 0f989f749b51ec1fd94bb5a42f8ad10c8b9f73cb upstream.

The patch "module: fix types of device tables aliases" newly requires that
invocations of

MODULE_DEVICE_TABLE(type, name);

come *after* the definition of `name'.  That is reasonable, but some
drivers weren't doing this.  Fix them.

Cc: James Bottomley 
Cc: Andrey Ryabinin 
Cc: David Miller 
Cc: Hans Verkuil 
Acked-by: Mauro Carvalho Chehab 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Save/restore XER in checkpointed register state

2017-01-15T14:49:49+00:00

[ Upstream commit 0d808df06a44200f52262b6eb72bcb6042f5a7c5 ]

When switching from/to a guest that has a transaction in progress,
we need to save/restore the checkpointed register state.  Although
XER is part of the CPU state that gets checkpointed, the code that
does this saving and restoring doesn't save/restore XER.

This fixes it by saving and restoring the XER.  To allow userspace
to read/write the checkpointed XER value, we also add a new ONE_REG
specifier.

The visible effect of this bug is that the guest may see its XER
value being corrupted when it uses transactions.

Fixes: e4e38121507a ("KVM: PPC: Book3S HV: Add transactional memory support")
Fixes: 0a8eccefcb34 ("KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Paul Mackerras 
Reviewed-by: Thomas Huth 
Signed-off-by: Paul Mackerras 
Signed-off-by: Sasha Levin

bus: arm-ccn: Provide required event arguments

2016-12-23T14:40:28+00:00

[ Upstream commit 8f06c51fac1ca4104b8b64872f310e28186aea42 ]

Since 688d4dfcdd624192cbf03c08402e444d1d11f294 "perf tools: Support
parsing parameterized events" the perf userspace tools understands
"argument=?" syntax in the events file, making sure that required
arguments are provided by the user and not defaulting to 0, causing
confusion.

This patch adds the required arguments lists for CCN events.

Signed-off-by: Pawel Moll 
Signed-off-by: Sasha Levin

Documentation/module-signing.txt: Note need for version info if reusing a key

2016-08-22T16:23:18+00:00

[ Upstream commit b8612e517c3c9809e1200b72c474dbfd969e5a83 ]

Signing a module should only make it trusted by the specific kernel it
was built for, not anything else.  If a module signing key is used for
multiple ABI-incompatible kernels, the modules need to include enough
version information to distinguish them.

Signed-off-by: Ben Hutchings 
Cc: stable@vger.kernel.org
Signed-off-by: Rusty Russell 
Signed-off-by: Sasha Levin

pipe: limit the per-user amount of pages allocated in pipes

2016-07-12T12:48:19+00:00

[ Upstream commit 759c01142a5d0f364a462346168a56de28a80f52 ]

On no-so-small systems, it is possible for a single process to cause an
OOM condition by filling large pipes with data that are never read. A
typical process filling 4000 pipes with 1 MB of data will use 4 GB of
memory. On small systems it may be tricky to set the pipe max size to
prevent this from happening.

This patch makes it possible to enforce a per-user soft limit above
which new pipes will be limited to a single page, effectively limiting
them to 4 kB each, as well as a hard limit above which no new pipes may
be created for this user. This has the effect of protecting the system
against memory abuse without hurting other users, and still allowing
pipes to work correctly though with less data at once.

The limit are controlled by two new sysctls : pipe-user-pages-soft, and
pipe-user-pages-hard. Both may be disabled by setting them to zero. The
default soft limit allows the default number of FDs per process (1024)
to create pipes of the default size (64kB), thus reaching a limit of 64MB
before starting to create only smaller pipes. With 256 processes limited
to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB =
1084 MB of memory allocated for a user. The hard limit is disabled by
default to avoid breaking existing applications that make intensive use
of pipes (eg: for splicing).

Reported-by: socketpair@gmail.com
Reported-by: Tetsuo Handa 
Mitigates: CVE-2013-4312 (Linux 2.0+)
Suggested-by: Linus Torvalds 
Signed-off-by: Willy Tarreau 
Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin

scsi: fix race between simultaneous decrements of ->host_failed

2016-07-11T15:10:54+00:00

[ Upstream commit 72d8c36ec364c82bf1bf0c64dfa1041cfaf139f7 ]

sas_ata_strategy_handler() adds the works of the ata error handler to
system_unbound_wq. This workqueue asynchronously runs work items, so the
ata error handler will be performed concurrently on different CPUs. In
this case, ->host_failed will be decreased simultaneously in
scsi_eh_finish_cmd() on different CPUs, and become abnormal.

It will lead to permanently inequality between ->host_failed and
->host_busy, and scsi error handler thread won't start running. IO
errors after that won't be handled.

Since all scmds must have been handled in the strategy handler, just
remove the decrement in scsi_eh_finish_cmd() and zero ->host_busy after
the strategy handler to fix this race.

Fixes: 50824d6c5657 ("[SCSI] libsas: async ata-eh")
Cc: stable@vger.kernel.org
Signed-off-by: Wei Fang 
Reviewed-by: James Bottomley 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin

crypto: s5p-sss - Remove useless hash interrupt handler

2016-06-03T15:30:28+00:00

[ Upstream commit 5512442553bbe8d4fcdba3e17b30f187706384a7 ]

Beside regular feed control interrupt, the driver requires also hash
interrupt for older SoCs (samsung,s5pv210-secss). However after
requesting it, the interrupt handler isn't doing anything with it, not
even clearing the hash interrupt bit.

Driver does not provide hash functions so it is safe to remove the hash
interrupt related code and to not require the interrupt in Device Tree.

Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Herbert Xu 
Signed-off-by: Sasha Levin