linux.git/lib/Kconfig.debug, branch v4.9-rc2

Merge tag 'linux-kselftest-4.9-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2016-10-14T22:17:12+00:00

Pull kselftest updates from Shuah Khan:
 "This update consists of:

   - Fixes and improvements to existing tests

   - Moving code from Documentation to selftests, samples, and tools:

     * Moves dnotify_test, prctl, ptp, vDSO, ia64, watchdog, and
       networking tests from Documentation to selftests.

     * Moves mic/mpssd, misc-devices/mei, timers, watchdog, auxdisplay,
       and blackfin examples from Documentation to samples.

     * Moves accounting, laptops/dslm, and pcmcia/crc32hash tools from
       Documentation to tools.

     * Deletes BUILD_DOCSRC and its dependencies"

* tag 'linux-kselftest-4.9-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (21 commits)
  selftests/futex: Check ANSI terminal color support
  Doc: update 00-INDEX files to reflect the runnable code move
  samples: move blackfin gptimers-example from Documentation
  tools: move pcmcia crc32hash tool from Documentation
  tools: move laptops dslm tool from Documentation
  tools: move accounting tool from Documentation
  samples: move auxdisplay example code from Documentation
  samples: move watchdog example code from Documentation
  samples: move timers example code from Documentation
  samples: move misc-devices/mei example code from Documentation
  samples: move mic/mpssd example code from Documentation
  selftests: Move networking/timestamping from Documentation
  selftests: move watchdog tests from Documentation/watchdog
  selftests: move ia64 tests from Documentation/ia64
  selftests: move vDSO tests from Documentation/vDSO
  selftests: move ptp tests from Documentation/ptp
  selftests: move prctl tests from Documentation/prctl
  selftests: move dnotify_test from Documentation/filesystems
  selftests/timers: Add missing error code assignment before test
  selftests/zram: replace ZRAM_LZ4_COMPRESS
  ...

samples: move blackfin gptimers-example from Documentation

2016-10-10T13:12:02+00:00

Move blackfin gptimers-example to samples and remove it from Documentation
Makefile. Update samples Kconfig and Makefile to build gptimers-example.

blackfin is the last CONFIG_BUILD_DOCSRC target in Documentation/Makefile.
Hence this patch also includes changes to remove CONFIG_BUILD_DOCSRC from
Makefile and lib/Kconfig.debug and updates VIDEO_PCI_SKELETON dependency
on BUILD_DOCSRC.

Documentation/Makefile is not deleted to avoid braking make htmldocs and
make distclean.

Acked-by: Michal Marek 
Acked-by: Jonathan Corbet 
Reviewed-by: Kees Cook 
Reported-by: Valentin Rothberg 
Reported-by: Paul Gortmaker 
Signed-off-by: Shuah Khan

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2016-10-07T19:24:08+00:00

Pull trivial updates from Jiri Kosina:
 "The usual rocket science from the trivial tree"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  tracing/syscalls: fix multiline in error message text
  lib/Kconfig.debug: fix DEBUG_SECTION_MISMATCH description
  doc: vfs: fix fadvise() sycall name
  x86/entry: spell EBX register correctly in documentation
  securityfs: fix securityfs_create_dir comment
  irq: Fix typo in tracepoint.xml

lib/Kconfig.debug: fix DEBUG_SECTION_MISMATCH description

2016-09-29T08:19:45+00:00

Signed-off-by: Uwe Kleine-König 
Signed-off-by: Jiri Kosina

locking/hung_task: Fix typo in CONFIG_DETECT_HUNG_TASK help text

2016-09-23T05:30:04+00:00

Fix the indefinitiley -> indefinitely typo in Kconfig.debug.

Signed-off-by: Vivien Didelot 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20160922205513.17821-1-vivien.didelot@savoirfairelinux.com
Signed-off-by: Ingo Molnar

mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS

2016-08-30T17:10:21+00:00

There are three usercopy warnings which are currently being silenced for
gcc 4.6 and newer:

1) "copy_from_user() buffer size is too small" compile warning/error

   This is a static warning which happens when object size and copy size
   are both const, and copy size > object size.  I didn't see any false
   positives for this one.  So the function warning attribute seems to
   be working fine here.

   Note this scenario is always a bug and so I think it should be
   changed to *always* be an error, regardless of
   CONFIG_DEBUG_STRICT_USER_COPY_CHECKS.

2) "copy_from_user() buffer size is not provably correct" compile warning

   This is another static warning which happens when I enable
   __compiletime_object_size() for new compilers (and
   CONFIG_DEBUG_STRICT_USER_COPY_CHECKS).  It happens when object size
   is const, but copy size is *not*.  In this case there's no way to
   compare the two at build time, so it gives the warning.  (Note the
   warning is a byproduct of the fact that gcc has no way of knowing
   whether the overflow function will be called, so the call isn't dead
   code and the warning attribute is activated.)

   So this warning seems to only indicate "this is an unusual pattern,
   maybe you should check it out" rather than "this is a bug".

   I get 102(!) of these warnings with allyesconfig and the
   __compiletime_object_size() gcc check removed.  I don't know if there
   are any real bugs hiding in there, but from looking at a small
   sample, I didn't see any.  According to Kees, it does sometimes find
   real bugs.  But the false positive rate seems high.

3) "Buffer overflow detected" runtime warning

   This is a runtime warning where object size is const, and copy size >
   object size.

All three warnings (both static and runtime) were completely disabled
for gcc 4.6 with the following commit:

  2fb0815c9ee6 ("gcc4: disable __compiletime_object_size for GCC 4.6+")

That commit mistakenly assumed that the false positives were caused by a
gcc bug in __compiletime_object_size().  But in fact,
__compiletime_object_size() seems to be working fine.  The false
positives were instead triggered by #2 above.  (Though I don't have an
explanation for why the warnings supposedly only started showing up in
gcc 4.6.)

So remove warning #2 to get rid of all the false positives, and re-enable
warnings #1 and #3 by reverting the above commit.

Furthermore, since #1 is a real bug which is detected at compile time,
upgrade it to always be an error.

Having done all that, CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is no longer
needed.

Signed-off-by: Josh Poimboeuf 
Cc: Kees Cook 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H . Peter Anvin" 
Cc: Andy Lutomirski 
Cc: Steven Rostedt 
Cc: Brian Gerst 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Cc: Byungchul Park 
Cc: Nilay Vaish 
Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2016-08-03T01:08:07+00:00

Merge yet more updates from Andrew Morton:

 - the rest of ocfs2

 - various hotfixes, mainly MM

 - quite a bit of misc stuff - drivers, fork, exec, signals, etc.

 - printk updates

 - firmware

 - checkpatch

 - nilfs2

 - more kexec stuff than usual

 - rapidio updates

 - w1 things

* emailed patches from Andrew Morton : (111 commits)
  ipc: delete "nr_ipc_ns"
  kcov: allow more fine-grained coverage instrumentation
  init/Kconfig: add clarification for out-of-tree modules
  config: add android config fragments
  init/Kconfig: ban CONFIG_LOCALVERSION_AUTO with allmodconfig
  relay: add global mode support for buffer-only channels
  init: allow blacklisting of module_init functions
  w1:omap_hdq: fix regression
  w1: add helper macro module_w1_family
  w1: remove need for ida and use PLATFORM_DEVID_AUTO
  rapidio/switches: add driver for IDT gen3 switches
  powerpc/fsl_rio: apply changes for RIO spec rev 3
  rapidio: modify for rev.3 specification changes
  rapidio: change inbound window size type to u64
  rapidio/idt_gen2: fix locking warning
  rapidio: fix error handling in mbox request/release functions
  rapidio/tsi721_dma: advance queue processing from transfer submit call
  rapidio/tsi721: add messaging mbox selector parameter
  rapidio/tsi721: add PCIe MRRS override parameter
  rapidio/tsi721_dma: add channel mask and queue size parameters
  ...

kcov: allow more fine-grained coverage instrumentation

2016-08-02T23:35:43+00:00

For more targeted fuzzing, it's better to disable kernel-wide
instrumentation and instead enable it on a per-subsystem basis.  This
follows the pattern of UBSAN and allows you to compile in the kcov
driver without instrumenting the whole kernel.

To instrument a part of the kernel, you can use either

    # for a single file in the current directory
    KCOV_INSTRUMENT_filename.o := y

or

    # for all the files in the current directory (excluding subdirectories)
    KCOV_INSTRUMENT := y

or

    # (same as above)
    ccflags-y += $(CFLAGS_KCOV)

or

    # for all the files in the current directory (including subdirectories)
    subdir-ccflags-y += $(CFLAGS_KCOV)

Link: http://lkml.kernel.org/r/1464008380-11405-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum 
Cc: Dmitry Vyukov 
Cc: Quentin Casasnovas 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

2016-08-02T20:37:12+00:00

Pull kbuild updates from Michal Marek:

 - GCC plugin support by Emese Revfy from grsecurity, with a fixup from
   Kees Cook.  The plugins are meant to be used for static analysis of
   the kernel code.  Two plugins are provided already.

 - reduction of the gcc commandline by Arnd Bergmann.

 - IS_ENABLED / IS_REACHABLE macro enhancements by Masahiro Yamada

 - bin2c fix by Michael Tautschnig

 - setlocalversion fix by Wolfram Sang

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  gcc-plugins: disable under COMPILE_TEST
  kbuild: Abort build on bad stack protector flag
  scripts: Fix size mismatch of kexec_purgatory_size
  kbuild: make samples depend on headers_install
  Kbuild: don't add obj tree in additional includes
  Kbuild: arch: look for generated headers in obtree
  Kbuild: always prefix objtree in LINUXINCLUDE
  Kbuild: avoid duplicate include path
  Kbuild: don't add ../../ to include path
  vmlinux.lds.h: replace config_enabled() with IS_ENABLED()
  kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion
  kconfig.h: use already defined macros for IS_REACHABLE() define
  export.h: use __is_defined() to check if __KSYM_* is defined
  kconfig.h: use __is_defined() to check if MODULE is defined
  kbuild: setlocalversion: print error to STDERR
  Add sancov plugin
  Add Cyclomatic complexity GCC plugin
  GCC plugin infrastructure
  Shared library support

mm/page_owner: use stackdepot to store stacktrace

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

Currently, we store each page's allocation stacktrace on corresponding
page_ext structure and it requires a lot of memory.  This causes the
problem that memory tight system doesn't work well if page_owner is
enabled.  Moreover, even with this large memory consumption, we cannot
get full stacktrace because we allocate memory at boot time and just
maintain 8 stacktrace slots to balance memory consumption.  We could
increase it to more but it would make system unusable or change system
behaviour.

To solve the problem, this patch uses stackdepot to store stacktrace.
It obviously provides memory saving but there is a drawback that
stackdepot could fail.

stackdepot allocates memory at runtime so it could fail if system has
not enough memory.  But, most of allocation stack are generated at very
early time and there are much memory at this time.  So, failure would
not happen easily.  And, one failure means that we miss just one page's
allocation stacktrace so it would not be a big problem.  In this patch,
when memory allocation failure happens, we store special stracktrace
handle to the page that is failed to save stacktrace.  With it, user can
guess memory usage properly even if failure happens.

Memory saving looks as following.  (4GB memory system with page_owner)
(before the patch -> after the patch)

static allocation:
92274688 bytes -> 25165824 bytes

dynamic allocation after boot + kernel build:
0 bytes -> 327680 bytes

total:
92274688 bytes -> 25493504 bytes

72% reduction in total.

Note that implementation looks complex than someone would imagine
because there is recursion issue.  stackdepot uses page allocator and
page_owner is called at page allocation.  Using stackdepot in page_owner
could re-call page allcator and then page_owner.  That is a recursion.
To detect and avoid it, whenever we obtain stacktrace, recursion is
checked and page_owner is set to dummy information if found.  Dummy
information means that this page is allocated for page_owner feature
itself (such as stackdepot) and it's understandable behavior for user.

[iamjoonsoo.kim@lge.com: mm-page_owner-use-stackdepot-to-store-stacktrace-v3]
  Link: http://lkml.kernel.org/r/1464230275-25791-6-git-send-email-iamjoonsoo.kim@lge.com
  Link: http://lkml.kernel.org/r/1466150259-27727-7-git-send-email-iamjoonsoo.kim@lge.com
Link: http://lkml.kernel.org/r/1464230275-25791-6-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim 
Acked-by: Vlastimil Babka 
Acked-by: Michal Hocko 
Cc: Mel Gorman 
Cc: Minchan Kim 
Cc: Alexander Potapenko 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds