linux-toradex.git/mm/Makefile, branch v4.12

mm: add arch-independent testcases for RODATA

2017-02-28T02:43:48+00:00

This patch makes arch-independent testcases for RODATA.  Both x86 and
x86_64 already have testcases for RODATA, But they are arch-specific
because using inline assembly directly.

And cacheflush.h is not a suitable location for rodata-test related
things.  Since they were in cacheflush.h, If someone change the state of
CONFIG_DEBUG_RODATA_TEST, It cause overhead of kernel build.

To solve the above issues, write arch-independent testcases and move it
to shared location.

[jinb.park7@gmail.com: fix config dependency]
  Link: http://lkml.kernel.org/r/20170209131625.GA16954@pjb1027-Latitude-E5410
Link: http://lkml.kernel.org/r/20170129105436.GA9303@pjb1027-Latitude-E5410
Signed-off-by: Jinbum Park 
Acked-by: Kees Cook 
Cc: Ingo Molnar 
Cc: H. Peter Anvin 
Cc: Arjan van de Ven 
Cc: Laura Abbott 
Cc: Russell King 
Cc: Valentin Rothberg 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce page_vma_mapped_walk()

2017-02-25T01:46:55+00:00

Introduce a new interface to check if a page is mapped into a vma.  It
aims to address shortcomings of page_check_address{,_transhuge}.

Existing interface is not able to handle PTE-mapped THPs: it only finds
the first PTE.  The rest lefted unnoticed.

page_vma_mapped_walk() iterates over all possible mapping of the page in
the vma.

Link: http://lkml.kernel.org/r/20170129173858.45174-3-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov 
Cc: Andrea Arcangeli 
Cc: Hillf Danton 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Srikar Dronamraju 
Cc: Vladimir Davydov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/swap: add cache for swap slots allocation

2017-02-23T00:41:30+00:00

We add per cpu caches for swap slots that can be allocated and freed
quickly without the need to touch the swap info lock.

Two separate caches are maintained for swap slots allocated and swap
slots returned.  This is to allow the swap slots to be returned to the
global pool in a batch so they will have a chance to be coaelesced with
other slots in a cluster.  We do not reuse the slots that are returned
right away, as it may increase fragmentation of the slots.

The swap allocation cache is protected by a mutex as we may sleep when
searching for empty slots in cache.  The swap free cache is protected by
a spin lock as we cannot sleep in the free path.

We refill the swap slots cache when we run out of slots, and we disable
the swap slots cache and drain the slots if the global number of slots
fall below a low watermark threshold.  We re-enable the cache agian when
the slots available are above a high watermark.

[ying.huang@intel.com: use raw_cpu_ptr over this_cpu_ptr for swap slots access]
[tim.c.chen@linux.intel.com: add comments on locks in swap_slots.h]
  Link: http://lkml.kernel.org/r/20170118180327.GA24225@linux.intel.com
Link: http://lkml.kernel.org/r/35de301a4eaa8daa2977de6e987f2c154385eb66.1484082593.git.tim.c.chen@linux.intel.com
Signed-off-by: Tim Chen 
Signed-off-by: "Huang, Ying" 
Reviewed-by: Michal Hocko 
Cc: Aaron Lu 
Cc: Andi Kleen 
Cc: Andrea Arcangeli 
Cc: Christian Borntraeger 
Cc: Dave Hansen 
Cc: Hillf Danton 
Cc: Huang Ying 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Jonathan Corbet  escreveu:
Cc: Kirill A. Shutemov 
Cc: Minchan Kim 
Cc: Rik van Riel 
Cc: Shaohua Li 
Cc: Vladimir Davydov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Disable the __builtin_return_address() warning globally after all

2016-10-12T17:23:41+00:00

This affectively reverts commit 377ccbb48373 ("Makefile: Mute warning
for __builtin_return_address(>0) for tracing only") because it turns out
that it really isn't tracing only - it's all over the tree.

We already also had the warning disabled separately for mm/usercopy.c
(which this commit also removes), and it turns out that we will also
want to disable it for get_lock_parent_ip(), that is used for at least
TRACE_IRQFLAGS.  Which (when enabled) ends up being all over the tree.

Steven Rostedt had a patch that tried to limit it to just the config
options that actually triggered this, but quite frankly, the extra
complexity and abstraction just isn't worth it.  We have never actually
had a case where the warning is actually useful, so let's just disable
it globally and not worry about it.

Acked-by: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Andrew Morton 
Cc: Ingo Molnar 
Cc: Peter Anvin 
Signed-off-by: Linus Torvalds

Merge tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2016-08-08T21:48:14+00:00

Pull usercopy protection from Kees Cook:
 "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and
  copy_from_user bounds checking for most architectures on SLAB and
  SLUB"

* tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  mm: SLUB hardened usercopy support
  mm: SLAB hardened usercopy support
  s390/uaccess: Enable hardened usercopy
  sparc/uaccess: Enable hardened usercopy
  powerpc/uaccess: Enable hardened usercopy
  ia64/uaccess: Enable hardened usercopy
  arm64/uaccess: Enable hardened usercopy
  ARM: uaccess: Enable hardened usercopy
  x86/uaccess: Enable hardened usercopy
  mm: Hardened usercopy
  mm: Implement stack frame object validation
  mm: Add is_migrate_cma_page

thp: extract khugepaged from mm/huge_memory.c

2016-07-26T23:19:19+00:00

khugepaged implementation grew to the point when it deserve separate
file in source.

Let's move it to mm/khugepaged.c.

Link: http://lkml.kernel.org/r/1466021202-61880-32-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: Hardened usercopy

2016-07-26T21:41:47+00:00

This is the start of porting PAX_USERCOPY into the mainline kernel. This
is the first set of features, controlled by CONFIG_HARDENED_USERCOPY. The
work is based on code by PaX Team and Brad Spengler, and an earlier port
from Casey Schaufler. Additional non-slab page tests are from Rik van Riel.

This patch contains the logic for validating several conditions when
performing copy_to_user() and copy_from_user() on the kernel object
being copied to/from:
- address range doesn't wrap around
- address range isn't NULL or zero-allocated (with a non-zero copy size)
- if on the slab allocator:
  - object size must be less than or equal to copy size (when check is
    implemented in the allocator, which appear in subsequent patches)
- otherwise, object must not span page allocations (excepting Reserved
  and CMA ranges)
- if on the stack
  - object must not extend before/after the current process stack
  - object must be contained by a valid stack frame (when there is
    arch/build support for identifying stack frames)
- object must not overlap with kernel text

Signed-off-by: Kees Cook 
Tested-by: Valdis Kletnieks 
Tested-by: Michael Ellerman

z3fold: the 3-fold allocator for compressed pages

2016-05-21T00:58:30+00:00

This patch introduces z3fold, a special purpose allocator for storing
compressed pages.  It is designed to store up to three compressed pages
per physical page.  It is a ZBUD derivative which allows for higher
compression ratio keeping the simplicity and determinism of its
predecessor.

This patch comes as a follow-up to the discussions at the Embedded Linux
Conference in San-Diego related to the talk [1].  The outcome of these
discussions was that it would be good to have a compressed page
allocator as stable and deterministic as zbud with with higher
compression ratio.

To keep the determinism and simplicity, z3fold, just like zbud, always
stores an integral number of compressed pages per page, but it can store
up to 3 pages unlike zbud which can store at most 2.  Therefore the
compression ratio goes to around 2.6x while zbud's one is around 1.7x.

The patch is based on the latest linux.git tree.

This version has been updated after testing on various simulators (e.g.
ARM Versatile Express, MIPS Malta, x86_64/Haswell) and basing on
comments from Dan Streetman [3].

[1] https://openiotelc2016.sched.org/event/6DAC/swapping-and-embedded-compression-relieves-the-pressure-vitaly-wool-softprise-consulting-ou
[2] https://lkml.org/lkml/2016/4/21/799
[3] https://lkml.org/lkml/2016/5/4/852

Link: http://lkml.kernel.org/r/20160509151753.ec3f9fda3c9898d31ff52a32@gmail.com
Signed-off-by: Vitaly Wool 
Cc: Seth Jennings 
Cc: Dan Streetman 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, kasan: SLAB support

2016-03-25T23:37:42+00:00

Add KASAN hooks to SLAB allocator.

This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.

Signed-off-by: Alexander Potapenko 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Andrey Konovalov 
Cc: Dmitry Vyukov 
Cc: Andrey Ryabinin 
Cc: Steven Rostedt 
Cc: Konstantin Serebryany 
Cc: Dmitry Chernenkov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel: add kcov code coverage

2016-03-22T22:36:02+00:00

kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing).  Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system.  A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/).  However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.

kcov does not aim to collect as much coverage as possible.  It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g.  scheduler, locking).

Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes.  Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch).  I've
dropped the second mode for simplicity.

This patch adds the necessary support on kernel side.  The complimentary
compiler support was added in gcc revision 231296.

We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:

  https://github.com/google/syzkaller/wiki/Found-Bugs

We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation".  For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.

Why not gcov.  Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat.  A
typical coverage can be just a dozen of basic blocks (e.g.  an invalid
input).  In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M).  Cost of
kcov depends only on number of executed basic blocks/edges.  On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.

kcov exposes kernel PCs and control flow to user-space which is
insecure.  But debugfs should not be mapped as user accessible.

Based on a patch by Quentin Casasnovas.

[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: Dmitry Vyukov 
Reviewed-by: Kees Cook 
Cc: syzkaller 
Cc: Vegard Nossum 
Cc: Catalin Marinas 
Cc: Tavis Ormandy 
Cc: Will Deacon 
Cc: Quentin Casasnovas 
Cc: Kostya Serebryany 
Cc: Eric Dumazet 
Cc: Alexander Potapenko 
Cc: Kees Cook 
Cc: Bjorn Helgaas 
Cc: Sasha Levin 
Cc: David Drysdale 
Cc: Ard Biesheuvel 
Cc: Andrey Ryabinin 
Cc: Kirill A. Shutemov 
Cc: Jiri Slaby 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds