Commit Graph

601 Commits

Author SHA1 Message Date
Linus Torvalds 9a61df9e5f Kbuild updates for v4.16 (2nd)
Makefile changes:
 - enable unused-variable warning that was wrongly disabled for clang
 
 Kconfig changes:
 - warn blank 'help' and fix existing instances
 - fix 'choice' behavior to not write out invisible symbols
 - fix misc weirdness
 
 Coccinell changes:
 - fix false positive of free after managed memory alloc detection
 - improve performance of NULL dereference detection
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Merge tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:
 "Makefile changes:
   - enable unused-variable warning that was wrongly disabled for clang

  Kconfig changes:
   - warn about blank 'help' and fix existing instances
   - fix 'choice' behavior to not write out invisible symbols
   - fix misc weirdness

  Coccinell changes:
   - fix false positive of free after managed memory alloc detection
   - improve performance of NULL dereference detection"

* tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits)
  kconfig: remove const qualifier from sym_expand_string_value()
  kconfig: add xrealloc() helper
  kconfig: send error messages to stderr
  kconfig: echo stdin to stdout if either is redirected
  kconfig: remove check_stdin()
  kconfig: remove 'config*' pattern from .gitignnore
  kconfig: show '?' prompt even if no help text is available
  kconfig: do not write choice values when their dependency becomes n
  coccinelle: deref_null: avoid useless computation
  coccinelle: devm_free: reduce false positives
  kbuild: clang: disable unused variable warnings only when constant
  kconfig: Warn if help text is blank
  nios2: kconfig: Remove blank help text
  arm: vt8500: kconfig: Remove blank help text
  MIPS: kconfig: Remove blank help text
  MIPS: BCM63XX: kconfig: Remove blank help text
  lib/Kconfig.debug: Remove blank help text
  Staging: rtl8192e: kconfig: Remove blank help text
  Staging: rtl8192u: kconfig: Remove blank help text
  mmc: kconfig: Remove blank help text
  ...
2018-02-09 19:32:41 -08:00
Arnd Bergmann e7c52b84fb kasan: rework Kconfig settings
We get a lot of very large stack frames using gcc-7.0.1 with the default
-fsanitize-address-use-after-scope --param asan-stack=1 options, which can
easily cause an overflow of the kernel stack, e.g.

  drivers/gpu/drm/i915/gvt/handlers.c:2434:1: warning: the frame size of 46176 bytes is larger than 3072 bytes
  drivers/net/wireless/ralink/rt2x00/rt2800lib.c:5650:1: warning: the frame size of 23632 bytes is larger than 3072 bytes
  lib/atomic64_test.c:250:1: warning: the frame size of 11200 bytes is larger than 3072 bytes
  drivers/gpu/drm/i915/gvt/handlers.c:2621:1: warning: the frame size of 9208 bytes is larger than 3072 bytes
  drivers/media/dvb-frontends/stv090x.c:3431:1: warning: the frame size of 6816 bytes is larger than 3072 bytes
  fs/fscache/stats.c:287:1: warning: the frame size of 6536 bytes is larger than 3072 bytes

To reduce this risk, -fsanitize-address-use-after-scope is now split out
into a separate CONFIG_KASAN_EXTRA Kconfig option, leading to stack
frames that are smaller than 2 kilobytes most of the time on x86_64.  An
earlier version of this patch also prevented combining KASAN_EXTRA with
KASAN_INLINE, but that is no longer necessary with gcc-7.0.1.

All patches to get the frame size below 2048 bytes with CONFIG_KASAN=y
and CONFIG_KASAN_EXTRA=n have been merged by maintainers now, so we can
bring back that default now.  KASAN_EXTRA=y still causes lots of
warnings but now defaults to !COMPILE_TEST to disable it in
allmodconfig, and it remains disabled in all other defconfigs since it
is a new option.  I arbitrarily raise the warning limit for KASAN_EXTRA
to 3072 to reduce the noise, but an allmodconfig kernel still has around
50 warnings on gcc-7.

I experimented a bit more with smaller stack frames and have another
follow-up series that reduces the warning limit for 64-bit architectures
to 1280 bytes (without CONFIG_KASAN).

With earlier versions of this patch series, I also had patches to address
the warnings we get with KASAN and/or KASAN_EXTRA, using a
"noinline_if_stackbloat" annotation.

That annotation now got replaced with a gcc-8 bugfix (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715) and a workaround for
older compilers, which means that KASAN_EXTRA is now just as bad as
before and will lead to an instant stack overflow in a few extreme
cases.

This reverts parts of commit 3f181b4d86 ("lib/Kconfig.debug: disable
-Wframe-larger-than warnings with KASAN=y").  Two patches in linux-next
should be merged first to avoid introducing warnings in an allmodconfig
build:
  3cd890dbe2 ("media: dvb-frontends: fix i2c access helpers for KASAN")
  16c3ada89c ("media: r820t: fix r820t_write_reg for KASAN")

Do we really need to backport this?

I think we do: without this patch, enabling KASAN will lead to
unavoidable kernel stack overflow in certain device drivers when built
with gcc-7 or higher on linux-4.10+ or any version that contains a
backport of commit c5caf21ab0.  Most people are probably still on
older compilers, but it will get worse over time as they upgrade their
distros.

The warnings we get on kernels older than this should all be for code
that uses dangerously large stack frames, though most of them do not
cause an actual stack overflow by themselves.The asan-stack option was
added in linux-4.0, and commit 3f181b4d86 ("lib/Kconfig.debug:
disable -Wframe-larger-than warnings with KASAN=y") effectively turned
off the warning for allmodconfig kernels, so I would like to see this
fix backported to any kernels later than 4.0.

I have done dozens of fixes for individual functions with stack frames
larger than 2048 bytes with asan-stack, and I plan to make sure that
all those fixes make it into the stable kernels as well (most are
already there).

Part of the complication here is that asan-stack (from 4.0) was
originally assumed to always require much larger stacks, but that
turned out to be a combination of multiple gcc bugs that we have now
worked around and fixed, but sanitize-address-use-after-scope (from
v4.10) has a much higher inherent stack usage and also suffers from at
least three other problems that we have analyzed but not yet fixed
upstream, each of them makes the stack usage more severe than it should
be.

Link: http://lkml.kernel.org/r/20171221134744.2295529-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06 18:32:47 -08:00
Vincent Legoll d3deafaa8b lib/: make RUNTIME_TESTS a menuconfig to ease disabling it all
No need to get into the submenu to disable all related config entries.

This makes it easier to disable all RUNTIME_TESTS config options without
entering the submenu.  It will also enable one to see that en/dis-abled
state from the outside menu.

This is only intended to change menuconfig UI, not change the config
dependencies.

Link: http://lkml.kernel.org/r/20171209162742.7363-1-vincent.legoll@gmail.com
Signed-off-by: Vincent Legoll <vincent.legoll@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06 18:32:44 -08:00
Yury Norov dceeb3e7fd lib/test_find_bit.c: rename to find_bit_benchmark.c
As suggested in review comments, rename test_find_bit.c to
find_bit_benchmark.c.

Link: http://lkml.kernel.org/r/20171124143040.a44jvhmnaiyedg2i@yury-thinkpad
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Clement Courbet <courbet@google.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06 18:32:44 -08:00
Ulf Magnusson e0371b8be7 lib/Kconfig.debug: Remove blank help text
Blank help texts are probably either a typo, a Kconfig misunderstanding,
or some kind of half-committing to adding a help text (in which case a
TODO comment would be clearer, if the help text really can't be added
right away).

Best to remove them, IMO.

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-02-02 23:53:10 +09:00
Linus Torvalds b2fe5fa686 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:

 1) Significantly shrink the core networking routing structures. Result
    of http://vger.kernel.org/~davem/seoul2017_netdev_keynote.pdf

 2) Add netdevsim driver for testing various offloads, from Jakub
    Kicinski.

 3) Support cross-chip FDB operations in DSA, from Vivien Didelot.

 4) Add a 2nd listener hash table for TCP, similar to what was done for
    UDP. From Martin KaFai Lau.

 5) Add eBPF based queue selection to tun, from Jason Wang.

 6) Lockless qdisc support, from John Fastabend.

 7) SCTP stream interleave support, from Xin Long.

 8) Smoother TCP receive autotuning, from Eric Dumazet.

 9) Lots of erspan tunneling enhancements, from William Tu.

10) Add true function call support to BPF, from Alexei Starovoitov.

11) Add explicit support for GRO HW offloading, from Michael Chan.

12) Support extack generation in more netlink subsystems. From Alexander
    Aring, Quentin Monnet, and Jakub Kicinski.

13) Add 1000BaseX, flow control, and EEE support to mvneta driver. From
    Russell King.

14) Add flow table abstraction to netfilter, from Pablo Neira Ayuso.

15) Many improvements and simplifications to the NFP driver bpf JIT,
    from Jakub Kicinski.

16) Support for ipv6 non-equal cost multipath routing, from Ido
    Schimmel.

17) Add resource abstration to devlink, from Arkadi Sharshevsky.

18) Packet scheduler classifier shared filter block support, from Jiri
    Pirko.

19) Avoid locking in act_csum, from Davide Caratti.

20) devinet_ioctl() simplifications from Al viro.

21) More TCP bpf improvements from Lawrence Brakmo.

22) Add support for onlink ipv6 route flag, similar to ipv4, from David
    Ahern.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1925 commits)
  tls: Add support for encryption using async offload accelerator
  ip6mr: fix stale iterator
  net/sched: kconfig: Remove blank help texts
  openvswitch: meter: Use 64-bit arithmetic instead of 32-bit
  tcp_nv: fix potential integer overflow in tcpnv_acked
  r8169: fix RTL8168EP take too long to complete driver initialization.
  qmi_wwan: Add support for Quectel EP06
  rtnetlink: enable IFLA_IF_NETNSID for RTM_NEWLINK
  ipmr: Fix ptrdiff_t print formatting
  ibmvnic: Wait for device response when changing MAC
  qlcnic: fix deadlock bug
  tcp: release sk_frag.page in tcp_disconnect
  ipv4: Get the address of interface correctly.
  net_sched: gen_estimator: fix lockdep splat
  net: macb: Handle HRESP error
  net/mlx5e: IPoIB, Fix copy-paste bug in flow steering refactoring
  ipv6: addrconf: break critical section in addrconf_verify_rtnl()
  ipv6: change route cache aging logic
  i40e/i40evf: Update DESC_NEEDED value to reflect larger value
  bnxt_en: cleanup DIM work on device shutdown
  ...
2018-01-31 14:31:10 -08:00
Linus Torvalds c1488798ad Merge branch 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull STRICT_DEVMEM default from Ingo Molnar:
 "Make CONFIG_STRICT_DEVMEM default-y on x86 and arm64 as well, to
  follow the distro status quo"

* 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Kconfig: Make STRICT_DEVMEM default-y on x86 and arm64
2018-01-30 10:11:26 -08:00
Masami Hiramatsu 4b1a29a7f5 error-injection: Support fault injection framework
Support in-kernel fault-injection framework via debugfs.
This allows you to inject a conditional error to specified
function using debugfs interfaces.

Here is the result of test script described in
Documentation/fault-injection/fault-injection.txt

  ===========
  # ./test_fail_function.sh
  1+0 records in
  1+0 records out
  1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.0227404 s, 46.1 MB/s
  btrfs-progs v4.4
  See http://btrfs.wiki.kernel.org for more information.

  Label:              (null)
  UUID:               bfa96010-12e9-4360-aed0-42eec7af5798
  Node size:          16384
  Sector size:        4096
  Filesystem size:    1001.00MiB
  Block group profiles:
    Data:             single            8.00MiB
    Metadata:         DUP              58.00MiB
    System:           DUP              12.00MiB
  SSD detected:       no
  Incompat features:  extref, skinny-metadata
  Number of devices:  1
  Devices:
     ID        SIZE  PATH
      1  1001.00MiB  /dev/loop2

  mount: mount /dev/loop2 on /opt/tmpmnt failed: Cannot allocate memory
  SUCCESS!
  ===========

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-12 17:33:38 -08:00
Masami Hiramatsu 540adea380 error-injection: Separate error-injection from kprobe
Since error-injection framework is not limited to be used
by kprobes, nor bpf. Other kernel subsystems can use it
freely for checking safeness of error-injection, e.g.
livepatch, ftrace etc.
So this separate error-injection framework from kprobes.

Some differences has been made:

- "kprobe" word is removed from any APIs/structures.
- BPF_ALLOW_ERROR_INJECTION() is renamed to
  ALLOW_ERROR_INJECTION() since it is not limited for BPF too.
- CONFIG_FUNCTION_ERROR_INJECTION is the config item of this
  feature. It is automatically enabled if the arch supports
  error injection feature for kprobe or ftrace etc.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-12 17:33:38 -08:00
Ingo Molnar e966eaeeb6 locking/lockdep: Remove the cross-release locking checks
This code (CONFIG_LOCKDEP_CROSSRELEASE=y and CONFIG_LOCKDEP_COMPLETIONS=y),
while it found a number of old bugs initially, was also causing too many
false positives that caused people to disable lockdep - which is arguably
a worse overall outcome.

If we disable cross-release by default but keep the code upstream then
in practice the most likely outcome is that we'll allow the situation
to degrade gradually, by allowing entropy to introduce more and more
false positives, until it overwhelms maintenance capacity.

Another bad side effect was that people were trying to work around
the false positives by uglifying/complicating unrelated code. There's
a marked difference between annotating locking operations and
uglifying good code just due to bad lock debugging code ...

This gradual decrease in quality happened to a number of debugging
facilities in the kernel, and lockdep is pretty complex already,
so we cannot risk this outcome.

Either cross-release checking can be done right with no false positives,
or it should not be included in the upstream kernel.

( Note that it might make sense to maintain it out of tree and go through
  the false positives every now and then and see whether new bugs were
  introduced. )

Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-12-12 12:38:51 +01:00
Kees Cook 0f7cda2b82 Kconfig: Make STRICT_DEVMEM default-y on x86 and arm64
Distros have been shipping with CONFIG_STRICT_DEVMEM=y for years now. It
is probably time to flip this default for x86 and arm64.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: kernel-hardening@lists.openwall.com
Link: http://lkml.kernel.org/r/20171201201000.GA44539@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-12-11 18:41:26 +01:00
Victor Chibotaru d677a4d601 Makefile: support flag -fsanitizer-coverage=trace-cmp
The flag enables Clang instrumentation of comparison operations
(currently not supported by GCC).  This instrumentation is needed by the
new KCOV device to collect comparison operands.

Link: http://lkml.kernel.org/r/20171011095459.70721-2-glider@google.com
Signed-off-by: Victor Chibotaru <tchibo@google.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: <syzkaller@googlegroups.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17 16:10:04 -08:00
Yury Norov 4441fca0a2 lib: test module for find_*_bit() functions
find_bit functions are widely used in the kernel, including hot paths.
This module tests performance of those functions in 2 typical scenarios:
randomly filled bitmap with relatively equal distribution of set and
cleared bits, and sparse bitmap which has 1 set bit for 500 cleared
bits.

On ThunderX machine:

	 Start testing find_bit() with random-filled bitmap
	find_next_bit:          240043 cycles,  164062 iterations
	find_next_zero_bit:     312848 cycles,  163619 iterations
	find_last_bit:          193748 cycles,  164062 iterations
	find_first_bit:      177720874 cycles,  164062 iterations

	 Start testing find_bit() with sparse bitmap
	find_next_bit:            3633 cycles,     656 iterations
	find_next_zero_bit:     620399 cycles,  327025 iterations
	find_last_bit:            3038 cycles,     656 iterations
	find_first_bit:         691407 cycles,     656 iterations

[arnd@arndb.de: use correct format string for find-bit tests]
  Link: http://lkml.kernel.org/r/20171113135605.3166307-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20171109140714.13168-1-ynorov@caviumnetworks.com
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Clement Courbet <courbet@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17 16:10:02 -08:00
Linus Torvalds b9743042b3 Driver core patches for 4.15-rc1
Here is the set of driver core / debugfs patches for 4.15-rc1.
 
 Not many here, mostly all are debugfs fixes to resolve some
 long-reported problems with files going away with references to them in
 userspace.  There's also some SPDX cleanups for the debugfs code, as
 well as a few other minor driver core changes for issues reported by
 people.
 
 All of these have been in linux-next for a week or more with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the set of driver core / debugfs patches for 4.15-rc1.

  Not many here, mostly all are debugfs fixes to resolve some
  long-reported problems with files going away with references to them
  in userspace. There's also some SPDX cleanups for the debugfs code, as
  well as a few other minor driver core changes for issues reported by
  people.

  All of these have been in linux-next for a week or more with no
  reported issues"

* tag 'driver-core-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  driver core: Fix device link deferred probe
  debugfs: Remove redundant license text
  debugfs: add SPDX identifiers to all debugfs files
  debugfs: defer debugfs_fsdata allocation to first usage
  debugfs: call debugfs_real_fops() only after debugfs_file_get()
  debugfs: purge obsolete SRCU based removal protection
  IB/hfi1: convert to debugfs_file_get() and -put()
  debugfs: convert to debugfs_file_get() and -put()
  debugfs: debugfs_real_fops(): drop __must_hold sparse annotation
  debugfs: implement per-file removal protection
  debugfs: add support for more elaborate ->d_fsdata
  driver core: Move device_links_purge() after bus_remove_device()
  arch_topology: Fix section miss match warning due to free_raw_capacity()
  driver-core: pr_err() strings should end with newlines
2017-11-16 08:55:30 -08:00
Levin, Alexander (Sasha Levin) 4675ff05de kmemcheck: rip it out
Fix up makefiles, remove references, and git rm kmemcheck.

Link: http://lkml.kernel.org/r/20171007030159.22241-4-alexander.levin@verizon.com
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Tim Hansen <devtimhansen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:05 -08:00
Linus Torvalds d6ec9d9a4d Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Ingo Molnar:
 "Note that in this cycle most of the x86 topics interacted at a level
  that caused them to be merged into tip:x86/asm - but this should be a
  temporary phenomenon, hopefully we'll back to the usual patterns in
  the next merge window.

  The main changes in this cycle were:

  Hardware enablement:

   - Add support for the Intel UMIP (User Mode Instruction Prevention)
     CPU feature. This is a security feature that disables certain
     instructions such as SGDT, SLDT, SIDT, SMSW and STR. (Ricardo Neri)

     [ Note that this is disabled by default for now, there are some
       smaller enhancements in the pipeline that I'll follow up with in
       the next 1-2 days, which allows this to be enabled by default.]

   - Add support for the AMD SEV (Secure Encrypted Virtualization) CPU
     feature, on top of SME (Secure Memory Encryption) support that was
     added in v4.14. (Tom Lendacky, Brijesh Singh)

   - Enable new SSE/AVX/AVX512 CPU features: AVX512_VBMI2, GFNI, VAES,
     VPCLMULQDQ, AVX512_VNNI, AVX512_BITALG. (Gayatri Kammela)

  Other changes:

   - A big series of entry code simplifications and enhancements (Andy
     Lutomirski)

   - Make the ORC unwinder default on x86 and various objtool
     enhancements. (Josh Poimboeuf)

   - 5-level paging enhancements (Kirill A. Shutemov)

   - Micro-optimize the entry code a bit (Borislav Petkov)

   - Improve the handling of interdependent CPU features in the early
     FPU init code (Andi Kleen)

   - Build system enhancements (Changbin Du, Masahiro Yamada)

   - ... plus misc enhancements, fixes and cleanups"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (118 commits)
  x86/build: Make the boot image generation less verbose
  selftests/x86: Add tests for the STR and SLDT instructions
  selftests/x86: Add tests for User-Mode Instruction Prevention
  x86/traps: Fix up general protection faults caused by UMIP
  x86/umip: Enable User-Mode Instruction Prevention at runtime
  x86/umip: Force a page fault when unable to copy emulated result to user
  x86/umip: Add emulation code for UMIP instructions
  x86/cpufeature: Add User-Mode Instruction Prevention definitions
  x86/insn-eval: Add support to resolve 16-bit address encodings
  x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode
  x86/insn-eval: Add wrapper function for 32 and 64-bit addresses
  x86/insn-eval: Add support to resolve 32-bit address encodings
  x86/insn-eval: Compute linear address in several utility functions
  resource: Fix resource_size.cocci warnings
  X86/KVM: Clear encryption attribute when SEV is active
  X86/KVM: Decrypt shared per-cpu variables when SEV is active
  percpu: Introduce DEFINE_PER_CPU_DECRYPTED
  x86: Add support for changing memory encryption attribute in early boot
  x86/io: Unroll string I/O when SEV is active
  x86/boot: Add early boot support when running with SEV active
  ...
2017-11-13 14:13:48 -08:00
Nicolai Stange c9afbec270 debugfs: purge obsolete SRCU based removal protection
Purge the SRCU based file removal race protection in favour of the new,
refcount based debugfs_file_get()/debugfs_file_put() API.

Fixes: 49d200deaa ("debugfs: prevent access to removed files' private data")
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-07 20:25:02 +01:00
Byungchul Park e121d64e16 locking/lockdep: Introduce CONFIG_BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK=y
Add a Kconfig knob that enables the lockdep "crossrelease_fullstack" boot parameter.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: amir73il@gmail.com
Cc: axboe@kernel.dk
Cc: darrick.wong@oracle.com
Cc: david@fromorbit.com
Cc: hch@infradead.org
Cc: idryomov@gmail.com
Cc: johan@kernel.org
Cc: johannes.berg@intel.com
Cc: kernel-team@lge.com
Cc: linux-block@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: oleg@redhat.com
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/1508921765-15396-7-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 12:19:02 +02:00
Byungchul Park 2dcd5adfb7 locking/lockdep: Remove the BROKEN flag from CONFIG_LOCKDEP_CROSSRELEASE and CONFIG_LOCKDEP_COMPLETIONS
Now that the performance regression is fixed, re-enable
CONFIG_LOCKDEP_CROSSRELEASE=y and CONFIG_LOCKDEP_COMPLETIONS=y.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: amir73il@gmail.com
Cc: axboe@kernel.dk
Cc: darrick.wong@oracle.com
Cc: david@fromorbit.com
Cc: hch@infradead.org
Cc: idryomov@gmail.com
Cc: johan@kernel.org
Cc: johannes.berg@intel.com
Cc: kernel-team@lge.com
Cc: linux-block@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: oleg@redhat.com
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/1508921765-15396-6-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 12:19:01 +02:00
Ingo Molnar f95b23a112 Merge branch 'x86/urgent' into x86/asm, to pick up dependent fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-23 13:30:47 +02:00
Linus Torvalds 60a6ca6c94 Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
 "Two lockdep fixes for bugs introduced by the cross-release dependency
  tracking feature - plus a commit that disables it because performance
  regressed in an absymal fashion on some systems"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Disable cross-release features for now
  locking/selftest: Avoid false BUG report
  locking/lockdep: Fix stacktrace mess
2017-10-14 15:14:20 -04:00
Ingo Molnar b483cf3bc2 locking/lockdep: Disable cross-release features for now
Johan Hovold reported a big lockdep slowdown on his system, caused by lockdep:

> I had noticed that the BeagleBone Black boot time appeared to have
> increased significantly with 4.14 and yesterday I finally had time to
> investigate it.
>
> Boot time (from "Linux version" to login prompt) had in fact doubled
> since 4.13 where it took 17 seconds (with my current config) compared to
> the 35 seconds I now see with 4.14-rc4.
>
> I quick bisect pointed to lockdep and specifically the following commit:
>
>	28a903f63e ("locking/lockdep: Handle non(or multi)-acquisition of a crosslock")

Because the final v4.14 release is close, disable the cross-release lockdep
features for now.

Bisected-by: Johan Hovold <johan@kernel.org>
Debugged-by: Johan Hovold <johan@kernel.org>
Reported-by: Johan Hovold <johan@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: kernel-team@lge.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mm@kvack.org
Cc: linux-omap@vger.kernel.org
Link: http://lkml.kernel.org/r/20171014072659.f2yr6mhm5ha3eou7@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-14 12:50:26 +02:00
Josh Poimboeuf 11af847446 x86/unwind: Rename unwinder config options to 'CONFIG_UNWINDER_*'
Rename the unwinder config options from:

  CONFIG_ORC_UNWINDER
  CONFIG_FRAME_POINTER_UNWINDER
  CONFIG_GUESS_UNWINDER

to:

  CONFIG_UNWINDER_ORC
  CONFIG_UNWINDER_FRAME_POINTER
  CONFIG_UNWINDER_GUESS

... in order to give them a more logical config namespace.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/73972fc7e2762e91912c6b9584582703d6f1b8cc.1507924831.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-14 10:12:12 +02:00
Randy Dunlap cc3fa84045 lib/Kconfig.debug: kernel hacking menu: runtime testing: keep tests together
Expand the "Runtime testing" menu by including more entries inside it
instead of after it.  This is just Kconfig symbol movement.

This causes the (arch-independent) Runtime tests to be presented
(listed) all in one place instead of in multiple places.

Link: http://lkml.kernel.org/r/c194e5c4-2042-bf94-a2d8-7aa13756e257@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Helge Deller 432654df90 parisc: Fix too large frame size warnings
The parisc architecture has larger stack frames than most other
architectures on 32-bit kernels.

Increase the maximum allowed stack frame to 1280 bytes for parisc to
avoid warnings in the do_sys_poll() and pat_memconfig() functions.

Signed-off-by: Helge Deller <deller@gmx.de>
2017-09-22 19:46:07 +02:00
Florian Fainelli e4dace3615 lib: add test module for CONFIG_DEBUG_VIRTUAL
Add a test module that allows testing that CONFIG_DEBUG_VIRTUAL works
correctly, at least that it can catch invalid calls to virt_to_phys()
against the non-linear kernel virtual address map.

Link: http://lkml.kernel.org/r/20170808164035.26725-1-f.fainelli@gmail.com
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:49 -07:00
Linus Torvalds 5f82e71a00 Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:

 - Add 'cross-release' support to lockdep, which allows APIs like
   completions, where it's not the 'owner' who releases the lock, to be
   tracked. It's all activated automatically under
   CONFIG_PROVE_LOCKING=y.

 - Clean up (restructure) the x86 atomics op implementation to be more
   readable, in preparation of KASAN annotations. (Dmitry Vyukov)

 - Fix static keys (Paolo Bonzini)

 - Add killable versions of down_read() et al (Kirill Tkhai)

 - Rework and fix jump_label locking (Marc Zyngier, Paolo Bonzini)

 - Rework (and fix) tlb_flush_pending() barriers (Peter Zijlstra)

 - Remove smp_mb__before_spinlock() and convert its usages, introduce
   smp_mb__after_spinlock() (Peter Zijlstra)

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (56 commits)
  locking/lockdep/selftests: Fix mixed read-write ABBA tests
  sched/completion: Avoid unnecessary stack allocation for COMPLETION_INITIALIZER_ONSTACK()
  acpi/nfit: Fix COMPLETION_INITIALIZER_ONSTACK() abuse
  locking/pvqspinlock: Relax cmpxchg's to improve performance on some architectures
  smp: Avoid using two cache lines for struct call_single_data
  locking/lockdep: Untangle xhlock history save/restore from task independence
  locking/refcounts, x86/asm: Disable CONFIG_ARCH_HAS_REFCOUNT for the time being
  futex: Remove duplicated code and fix undefined behaviour
  Documentation/locking/atomic: Finish the document...
  locking/lockdep: Fix workqueue crossrelease annotation
  workqueue/lockdep: 'Fix' flush_work() annotation
  locking/lockdep/selftests: Add mixed read-write ABBA tests
  mm, locking/barriers: Clarify tlb_flush_pending() barriers
  locking/lockdep: Make CONFIG_LOCKDEP_CROSSRELEASE and CONFIG_LOCKDEP_COMPLETIONS truly non-interactive
  locking/lockdep: Explicitly initialize wq_barrier::done::map
  locking/lockdep: Rename CONFIG_LOCKDEP_COMPLETE to CONFIG_LOCKDEP_COMPLETIONS
  locking/lockdep: Reword title of LOCKDEP_CROSSRELEASE config
  locking/lockdep: Make CONFIG_LOCKDEP_CROSSRELEASE part of CONFIG_PROVE_LOCKING
  locking/refcounts, x86/asm: Implement fast refcount overflow protection
  locking/lockdep: Fix the rollback and overwrite detection logic in crossrelease
  ...
2017-09-04 11:52:29 -07:00
Linus Torvalds b0c79f49c3 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:

 - Introduce the ORC unwinder, which can be enabled via
   CONFIG_ORC_UNWINDER=y.

   The ORC unwinder is a lightweight, Linux kernel specific debuginfo
   implementation, which aims to be DWARF done right for unwinding.
   Objtool is used to generate the ORC unwinder tables during build, so
   the data format is flexible and kernel internal: there's no
   dependency on debuginfo created by an external toolchain.

   The ORC unwinder is almost two orders of magnitude faster than the
   (out of tree) DWARF unwinder - which is important for perf call graph
   profiling. It is also significantly simpler and is coded defensively:
   there has not been a single ORC related kernel crash so far, even
   with early versions. (knock on wood!)

   But the main advantage is that enabling the ORC unwinder allows
   CONFIG_FRAME_POINTERS to be turned off - which speeds up the kernel
   measurably:

   With frame pointers disabled, GCC does not have to add frame pointer
   instrumentation code to every function in the kernel. The kernel's
   .text size decreases by about 3.2%, resulting in better cache
   utilization and fewer instructions executed, resulting in a broad
   kernel-wide speedup. Average speedup of system calls should be
   roughly in the 1-3% range - measurements by Mel Gorman [1] have shown
   a speedup of 5-10% for some function execution intense workloads.

   The main cost of the unwinder is that the unwinder data has to be
   stored in RAM: the memory cost is 2-4MB of RAM, depending on kernel
   config - which is a modest cost on modern x86 systems.

   Given how young the ORC unwinder code is it's not enabled by default
   - but given the performance advantages the plan is to eventually make
   it the default unwinder on x86.

   See Documentation/x86/orc-unwinder.txt for more details.

 - Remove lguest support: its intended role was that of a temporary
   proof of concept for virtualization, plus its removal will enable the
   reduction (removal) of the paravirt API as well, so Rusty agreed to
   its removal. (Juergen Gross)

 - Clean up and fix FSGS related functionality (Andy Lutomirski)

 - Clean up IO access APIs (Andy Shevchenko)

 - Enhance the symbol namespace (Jiri Slaby)

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
  objtool: Handle GCC stack pointer adjustment bug
  x86/entry/64: Use ENTRY() instead of ALIGN+GLOBAL for stub32_clone()
  x86/fpu/math-emu: Add ENDPROC to functions
  x86/boot/64: Extract efi_pe_entry() from startup_64()
  x86/boot/32: Extract efi_pe_entry() from startup_32()
  x86/lguest: Remove lguest support
  x86/paravirt/xen: Remove xen_patch()
  objtool: Fix objtool fallthrough detection with function padding
  x86/xen/64: Fix the reported SS and CS in SYSCALL
  objtool: Track DRAP separately from callee-saved registers
  objtool: Fix validate_branch() return codes
  x86: Clarify/fix no-op barriers for text_poke_bp()
  x86/switch_to/64: Rewrite FS/GS switching yet again to fix AMD CPUs
  selftests/x86/fsgsbase: Test selectors 1, 2, and 3
  x86/fsgsbase/64: Report FSBASE and GSBASE correctly in core dumps
  x86/fsgsbase/64: Fully initialize FS and GS state in start_thread_common
  x86/asm: Fix UNWIND_HINT_REGS macro for older binutils
  x86/asm/32: Fix regs_get_register() on segment registers
  x86/xen/64: Rearrange the SYSCALL entries
  x86/asm/32: Remove a bunch of '& 0xffff' from pt_regs segment reads
  ...
2017-09-04 09:52:57 -07:00
Ingo Molnar 10c9850cb2 Merge branch 'linus' into locking/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-25 11:04:51 +02:00
Thomas Gleixner 7edaeb6841 kernel/watchdog: Prevent false positives with turbo modes
The hardlockup detector on x86 uses a performance counter based on unhalted
CPU cycles and a periodic hrtimer. The hrtimer period is about 2/5 of the
performance counter period, so the hrtimer should fire 2-3 times before the
performance counter NMI fires. The NMI code checks whether the hrtimer
fired since the last invocation. If not, it assumess a hard lockup.

The calculation of those periods is based on the nominal CPU
frequency. Turbo modes increase the CPU clock frequency and therefore
shorten the period of the perf/NMI watchdog. With extreme Turbo-modes (3x
nominal frequency) the perf/NMI period is shorter than the hrtimer period
which leads to false positives.

A simple fix would be to shorten the hrtimer period, but that comes with
the side effect of more frequent hrtimer and softlockup thread wakeups,
which is not desired.

Implement a low pass filter, which checks the perf/NMI period against
kernel time. If the perf/NMI fires before 4/5 of the watchdog period has
elapsed then the event is ignored and postponed to the next perf/NMI.

That solves the problem and avoids the overhead of shorter hrtimer periods
and more frequent softlockup thread wakeups.

Fixes: 58687acba5 ("lockup_detector: Combine nmi_watchdog and softlockup detector")
Reported-and-tested-by: Kan Liang <Kan.liang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: dzickus@redhat.com
Cc: prarit@redhat.com
Cc: ak@linux.intel.com
Cc: babu.moger@oracle.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: acme@redhat.com
Cc: stable@vger.kernel.org
Cc: atomlin@redhat.com
Cc: akpm@linux-foundation.org
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708150931310.1886@nanos
2017-08-18 12:35:02 +02:00
Ingo Molnar e26f34a407 locking/lockdep: Make CONFIG_LOCKDEP_CROSSRELEASE and CONFIG_LOCKDEP_COMPLETIONS truly non-interactive
The syntax to turn Kconfig options into non-interactive ones is to not offer
interactive prompt help texts. Remove them.

Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17 12:49:40 +02:00
Byungchul Park ea3f2c0fdf locking/lockdep: Rename CONFIG_LOCKDEP_COMPLETE to CONFIG_LOCKDEP_COMPLETIONS
'complete' is an adjective and LOCKDEP_COMPLETE sounds like 'lockdep is complete',
so pick a better name that uses a noun.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/1502960261-16206-3-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17 11:38:55 +02:00
Byungchul Park 0f0a22260d locking/lockdep: Reword title of LOCKDEP_CROSSRELEASE config
Lockdep doesn't have to be made to work with crossrelease and just works
with them. Reword the title so that what the option does is clear.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/1502960261-16206-2-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17 11:38:55 +02:00
Byungchul Park d0541b0fa6 locking/lockdep: Make CONFIG_LOCKDEP_CROSSRELEASE part of CONFIG_PROVE_LOCKING
Crossrelease support added the CONFIG_LOCKDEP_CROSSRELEASE and CONFIG_LOCKDEP_COMPLETE
options. It makes little sense to enable them when PROVE_LOCKING is disabled.

Make them non-interative options and part of PROVE_LOCKING to simplify the UI.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/1502960261-16206-1-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17 11:38:54 +02:00
Byungchul Park cd8084f91c locking/lockdep: Apply crossrelease to completions
Although wait_for_completion() and its family can cause deadlock, the
lock correctness validator could not be applied to them until now,
because things like complete() are usually called in a different context
from the waiting context, which violates lockdep's assumption.

Thanks to CONFIG_LOCKDEP_CROSSRELEASE, we can now apply the lockdep
detector to those completion operations. Applied it.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: boqun.feng@gmail.com
Cc: kernel-team@lge.com
Cc: kirill@shutemov.name
Cc: npiggin@gmail.com
Cc: walken@google.com
Cc: willy@infradead.org
Link: http://lkml.kernel.org/r/1502089981-21272-10-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-10 12:29:10 +02:00
Byungchul Park b09be676e0 locking/lockdep: Implement the 'crossrelease' feature
Lockdep is a runtime locking correctness validator that detects and
reports a deadlock or its possibility by checking dependencies between
locks. It's useful since it does not report just an actual deadlock but
also the possibility of a deadlock that has not actually happened yet.
That enables problems to be fixed before they affect real systems.

However, this facility is only applicable to typical locks, such as
spinlocks and mutexes, which are normally released within the context in
which they were acquired. However, synchronization primitives like page
locks or completions, which are allowed to be released in any context,
also create dependencies and can cause a deadlock.

So lockdep should track these locks to do a better job. The 'crossrelease'
implementation makes these primitives also be tracked.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: boqun.feng@gmail.com
Cc: kernel-team@lge.com
Cc: kirill@shutemov.name
Cc: npiggin@gmail.com
Cc: walken@google.com
Cc: willy@infradead.org
Link: http://lkml.kernel.org/r/1502089981-21272-6-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-10 12:29:07 +02:00
Josh Poimboeuf a34a766ff9 x86/kconfig: Make it easier to switch to the new ORC unwinder
A couple of Kconfig changes which make it much easier to switch to the
new CONFIG_ORC_UNWINDER:

1) Remove x86 dependencies on CONFIG_FRAME_POINTER for lockdep,
   latencytop, and fault injection.  x86 has a 'guess' unwinder which
   just scans the stack for kernel text addresses.  It's not 100%
   accurate but in many cases it's good enough.  This allows those users
   who don't want the text overhead of the frame pointer or ORC
   unwinders to still use these features.  More importantly, this also
   makes it much more straightforward to disable frame pointers.

2) Make CONFIG_ORC_UNWINDER depend on !CONFIG_FRAME_POINTER.  While it
   would be possible to have both enabled, it doesn't really make sense
   to do so.  So enforce a sane configuration to prevent the user from
   making a dumb mistake.

With these changes, when you disable CONFIG_FRAME_POINTER, "make
oldconfig" will ask if you want to enable CONFIG_ORC_UNWINDER.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/9985fb91ce5005fe33ea5cc2a20f14bd33c61d03.1500938583.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-26 13:18:20 +02:00
Josh Poimboeuf ee9f8fce99 x86/unwind: Add the ORC unwinder
Add the new ORC unwinder which is enabled by CONFIG_ORC_UNWINDER=y.
It plugs into the existing x86 unwinder framework.

It relies on objtool to generate the needed .orc_unwind and
.orc_unwind_ip sections.

For more details on why ORC is used instead of DWARF, see
Documentation/x86/orc-unwinder.txt - but the short version is
that it's a simplified, fundamentally more robust debugninfo
data structure, which also allows up to two orders of magnitude
faster lookups than the DWARF unwinder - which matters to
profiling workloads like perf.

Thanks to Andy Lutomirski for the performance improvement ideas:
splitting the ORC unwind table into two parallel arrays and creating a
fast lookup table to search a subset of the unwind table.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/0a6cbfb40f8da99b7a45a1a8302dc6aef16ec812.1500938583.git.jpoimboe@redhat.com
[ Extended the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-26 13:18:20 +02:00
Linus Torvalds 52f6c588c7 Add wait_for_random_bytes() and get_random_*_wait() functions so that
callers can more safely get random bytes if they can block until the
 CRNG is initialized.
 
 Also print a warning if get_random_*() is called before the CRNG is
 initialized.  By default, only one single-line warning will be printed
 per boot.  If CONFIG_WARN_ALL_UNSEEDED_RANDOM is defined, then a
 warning will be printed for each function which tries to get random
 bytes before the CRNG is initialized.  This can get spammy for certain
 architecture types, so it is not enabled by default.
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Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

Pull random updates from Ted Ts'o:
 "Add wait_for_random_bytes() and get_random_*_wait() functions so that
  callers can more safely get random bytes if they can block until the
  CRNG is initialized.

  Also print a warning if get_random_*() is called before the CRNG is
  initialized. By default, only one single-line warning will be printed
  per boot. If CONFIG_WARN_ALL_UNSEEDED_RANDOM is defined, then a
  warning will be printed for each function which tries to get random
  bytes before the CRNG is initialized. This can get spammy for certain
  architecture types, so it is not enabled by default"

* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  random: reorder READ_ONCE() in get_random_uXX
  random: suppress spammy warnings about unseeded randomness
  random: warn when kernel uses unseeded randomness
  net/route: use get_random_int for random counter
  net/neighbor: use get_random_u32 for 32-bit hash random
  rhashtable: use get_random_u32 for hash_rnd
  ceph: ensure RNG is seeded before using
  iscsi: ensure RNG is seeded before use
  cifs: use get_random_u32 for 32-bit lock random
  random: add get_random_{bytes,u32,u64,int,long,once}_wait family
  random: add wait_for_random_bytes() API
2017-07-15 12:44:02 -07:00
Theodore Ts'o eecabf5674 random: suppress spammy warnings about unseeded randomness
Unfortunately, on some models of some architectures getting a fully
seeded CRNG is extremely difficult, and so this can result in dmesg
getting spammed for a surprisingly long time.  This is really bad from
a security perspective, and so architecture maintainers really need to
do what they can to get the CRNG seeded sooner after the system is
booted.  However, users can't do anything actionble to address this,
and spamming the kernel messages log will only just annoy people.

For developers who want to work on improving this situation,
CONFIG_WARN_UNSEEDED_RANDOM has been renamed to
CONFIG_WARN_ALL_UNSEEDED_RANDOM.  By default the kernel will always
print the first use of unseeded randomness.  This way, hopefully the
security obsessed will be happy that there is _some_ indication when
the kernel boots there may be a potential issue with that architecture
or subarchitecture.  To see all uses of unseeded randomness,
developers can enable CONFIG_WARN_ALL_UNSEEDED_RANDOM.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-07-15 12:19:28 -04:00
Luis R. Rodriguez d9c6a72d6f kmod: add test driver to stress test the module loader
This adds a new stress test driver for kmod: the kernel module loader.
The new stress test driver, test_kmod, is only enabled as a module right
now.  It should be possible to load this as built-in and load tests
early (refer to the force_init_test module parameter), however since a
lot of test can get a system out of memory fast we leave this disabled
for now.

Using a system with 1024 MiB of RAM can *easily* get your kernel OOM
fast with this test driver.

The test_kmod driver exposes API knobs for us to fine tune simple
request_module() and get_fs_type() calls.  Since these API calls only
allow each one parameter a test driver for these is rather simple.
Other factors that can help out test driver though are the number of
calls we issue and knowing current limitations of each.  This exposes
configuration as much as possible through userspace to be able to build
tests directly from userspace.

Since it allows multiple misc devices its will eventually (once we add a
knob to let us create new devices at will) also be possible to perform
more tests in parallel, provided you have enough memory.

We only enable tests we know work as of right now.

Demo screenshots:

 # tools/testing/selftests/kmod/kmod.sh
kmod_test_0001_driver: OK! - loading kmod test
kmod_test_0001_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0001_fs: OK! - loading kmod test
kmod_test_0001_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
kmod_test_0002_driver: OK! - loading kmod test
kmod_test_0002_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0002_fs: OK! - loading kmod test
kmod_test_0002_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
kmod_test_0003: OK! - loading kmod test
kmod_test_0003: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0004: OK! - loading kmod test
kmod_test_0004: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0005: OK! - loading kmod test
kmod_test_0005: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0006: OK! - loading kmod test
kmod_test_0006: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0005: OK! - loading kmod test
kmod_test_0005: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0006: OK! - loading kmod test
kmod_test_0006: OK! - Return value: 0 (SUCCESS), expected SUCCESS
XXX: add test restult for 0007
Test completed

You can also request for specific tests:

 # tools/testing/selftests/kmod/kmod.sh -t 0001
kmod_test_0001_driver: OK! - loading kmod test
kmod_test_0001_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0001_fs: OK! - loading kmod test
kmod_test_0001_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
Test completed

Lastly, the current available number of tests:

 # tools/testing/selftests/kmod/kmod.sh --help
Usage: tools/testing/selftests/kmod/kmod.sh [ -t <4-number-digit> ]
Valid tests: 0001-0009

0001 - Simple test - 1 thread  for empty string
0002 - Simple test - 1 thread  for modules/filesystems that do not exist
0003 - Simple test - 1 thread  for get_fs_type() only
0004 - Simple test - 2 threads for get_fs_type() only
0005 - multithreaded tests with default setup - request_module() only
0006 - multithreaded tests with default setup - get_fs_type() only
0007 - multithreaded tests with default setup test request_module() and get_fs_type()
0008 - multithreaded - push kmod_concurrent over max_modprobes for request_module()
0009 - multithreaded - push kmod_concurrent over max_modprobes for get_fs_type()

The following test cases currently fail, as such they are not currently
enabled by default:

 # tools/testing/selftests/kmod/kmod.sh -t 0008
 # tools/testing/selftests/kmod/kmod.sh -t 0009

To be sure to run them as intended please unload both of the modules:

  o test_module
  o xfs

And ensure they are not loaded on your system prior to testing them.  If
you use these paritions for your rootfs you can change the default test
driver used for get_fs_type() by exporting it into your environment.  For
example of other test defaults you can override refer to kmod.sh
allow_user_defaults().

Behind the scenes this is how we fine tune at a test case prior to
hitting a trigger to run it:

cat /sys/devices/virtual/misc/test_kmod0/config
echo -n "2" > /sys/devices/virtual/misc/test_kmod0/config_test_case
echo -n "ext4" > /sys/devices/virtual/misc/test_kmod0/config_test_fs
echo -n "80" > /sys/devices/virtual/misc/test_kmod0/config_num_threads
cat /sys/devices/virtual/misc/test_kmod0/config
echo -n "1" > /sys/devices/virtual/misc/test_kmod0/config_num_threads

Finally to trigger:

echo -n "1" > /sys/devices/virtual/misc/test_kmod0/trigger_config

The kmod.sh script uses the above constructs to build different test cases.

A bit of interpretation of the current failures follows, first two
premises:

a) When request_module() is used userspace figures out an optimized
   version of module order for us.  Once it finds the modules it needs, as
   per depmod symbol dep map, it will finit_module() the respective
   modules which are needed for the original request_module() request.

b) We have an optimization in place whereby if a kernel uses
   request_module() on a module already loaded we never bother userspace
   as the module already is loaded.  This is all handled by kernel/kmod.c.

A few things to consider to help identify root causes of issues:

0) kmod 19 has a broken heuristic for modules being assumed to be
   built-in to your kernel and will return 0 even though request_module()
   failed.  Upgrade to a newer version of kmod.

1) A get_fs_type() call for "xfs" will request_module() for "fs-xfs",
   not for "xfs".  The optimization in kernel described in b) fails to
   catch if we have a lot of consecutive get_fs_type() calls.  The reason
   is the optimization in place does not look for aliases.  This means two
   consecutive get_fs_type() calls will bump kmod_concurrent, whereas
   request_module() will not.

This one explanation why test case 0009 fails at least once for
get_fs_type().

2) If a module fails to load --- for whatever reason (kmod_concurrent
   limit reached, file not yet present due to rootfs switch, out of
   memory) we have a period of time during which module request for the
   same name either with request_module() or get_fs_type() will *also*
   fail to load even if the file for the module is ready.

This explains why *multiple* NULLs are possible on test 0009.

3) finit_module() consumes quite a bit of memory.

4) Filesystems typically also have more dependent modules than other
   modules, its important to note though that even though a get_fs_type()
   call does not incur additional kmod_concurrent bumps, since userspace
   loads dependencies it finds it needs via finit_module_fd(), it *will*
   take much more memory to load a module with a lot of dependencies.

Because of 3) and 4) we will easily run into out of memory failures with
certain tests.  For instance test 0006 fails on qemu with 1024 MiB of RAM.
It panics a box after reaping all userspace processes and still not
having enough memory to reap.

[arnd@arndb.de: add dependencies for test module]
  Link: http://lkml.kernel.org/r/20170630154834.3689272-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170628223155.26472-3-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-14 15:05:13 -07:00
Nicholas Piggin 05a4a95279 kernel/watchdog: split up config options
Split SOFTLOCKUP_DETECTOR from LOCKUP_DETECTOR, and split
HARDLOCKUP_DETECTOR_PERF from HARDLOCKUP_DETECTOR.

LOCKUP_DETECTOR implies the general boot, sysctl, and programming
interfaces for the lockup detectors.

An architecture that wants to use a hard lockup detector must define
HAVE_HARDLOCKUP_DETECTOR_PERF or HAVE_HARDLOCKUP_DETECTOR_ARCH.

Alternatively an arch can define HAVE_NMI_WATCHDOG, which provides the
minimum arch_touch_nmi_watchdog, and it otherwise does its own thing and
does not implement the LOCKUP_DETECTOR interfaces.

sparc is unusual in that it has started to implement some of the
interfaces, but not fully yet.  It should probably be converted to a full
HAVE_HARDLOCKUP_DETECTOR_ARCH.

[npiggin@gmail.com: fix]
  Link: http://lkml.kernel.org/r/20170617223522.66c0ad88@roar.ozlabs.ibm.com
Link: http://lkml.kernel.org/r/20170616065715.18390-4-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com>	[sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:02 -07:00
Luis R. Rodriguez 9308f2f9e7 test_sysctl: add dedicated proc sysctl test driver
The existing tools/testing/selftests/sysctl/ tests include two test
cases, but these use existing production kernel sysctl interfaces.  We
want to expand test coverage but we can't just be looking for random
safe production values to poke at, that's just insane!

Instead just dedicate a test driver for debugging purposes and port the
existing scripts to use it.  This will make it easier for further tests
to be added.

Subsequent patches will extend our test coverage for sysctl.

The stress test driver uses a new license (GPL on Linux, copyleft-next
outside of Linux).  Linus was fine with this [0] and later due to Ted's
and Alans's request ironed out an "or" language clause to use [1] which
is already present upstream.

[0] https://lkml.kernel.org/r/CA+55aFyhxcvD+q7tp+-yrSFDKfR0mOHgyEAe=f_94aKLsOu0Og@mail.gmail.com
[1] https://lkml.kernel.org/r/1495234558.7848.122.camel@linux.intel.com

Link: http://lkml.kernel.org/r/20170630224431.17374-2-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:00 -07:00
Davidlohr Bueso 0f789b6764 lib/interval_tree_test.c: allow the module to be compiled-in
Patch series "lib/interval_tree_test: some debugging improvements".

Here are some patches that update the interval_tree_test module allowing
users to pass finer grained options to run the actual test.

This patch (of 4):

It is a tristate after all, and also serves well for quick debugging.

Link: http://lkml.kernel.org/r/20170518174936.20265-2-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:35 -07:00
Linus Torvalds 650fc870a2 There has been a fair amount of activity in the docs tree this time
around.  Highlights include:
 
  - Conversion of a bunch of security documentation into RST
 
  - The conversion of the remaining DocBook templates by The Amazing
    Mauro Machine.  We can now drop the entire DocBook build chain.
 
  - The usual collection of fixes and minor updates.
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Merge tag 'docs-4.13' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "There has been a fair amount of activity in the docs tree this time
  around. Highlights include:

   - Conversion of a bunch of security documentation into RST

   - The conversion of the remaining DocBook templates by The Amazing
     Mauro Machine. We can now drop the entire DocBook build chain.

   - The usual collection of fixes and minor updates"

* tag 'docs-4.13' of git://git.lwn.net/linux: (90 commits)
  scripts/kernel-doc: handle DECLARE_HASHTABLE
  Documentation: atomic_ops.txt is core-api/atomic_ops.rst
  Docs: clean up some DocBook loose ends
  Make the main documentation title less Geocities
  Docs: Use kernel-figure in vidioc-g-selection.rst
  Docs: fix table problems in ras.rst
  Docs: Fix breakage with Sphinx 1.5 and upper
  Docs: Include the Latex "ifthen" package
  doc/kokr/howto: Only send regression fixes after -rc1
  docs-rst: fix broken links to dynamic-debug-howto in kernel-parameters
  doc: Document suitability of IBM Verse for kernel development
  Doc: fix a markup error in coding-style.rst
  docs: driver-api: i2c: remove some outdated information
  Documentation: DMA API: fix a typo in a function name
  Docs: Insert missing space to separate link from text
  doc/ko_KR/memory-barriers: Update control-dependencies example
  Documentation, kbuild: fix typo "minimun" -> "minimum"
  docs: Fix some formatting issues in request-key.rst
  doc: ReSTify keys-trusted-encrypted.txt
  doc: ReSTify keys-request-key.txt
  ...
2017-07-03 21:13:25 -07:00
Linus Torvalds 892ad5acca Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Add CONFIG_REFCOUNT_FULL=y to allow the disabling of the 'full'
     (robustness checked) refcount_t implementation with slightly lower
     runtime overhead. (Kees Cook)

     The lighter weight variant is the default. The two variants use the
     same API. Having this variant was a precondition by some
     maintainers to merge refcount_t cleanups.

   - Add lockdep support for rtmutexes (Peter Zijlstra)

   - liblockdep fixes and improvements (Sasha Levin, Ben Hutchings)

   - ... misc fixes and improvements"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits)
  locking/refcount: Remove the half-implemented refcount_sub() API
  locking/refcount: Create unchecked atomic_t implementation
  locking/rtmutex: Don't initialize lockdep when not required
  locking/selftest: Add RT-mutex support
  locking/selftest: Remove the bad unlock ordering test
  rt_mutex: Add lockdep annotations
  MAINTAINERS: Claim atomic*_t maintainership
  locking/x86: Remove the unused atomic_inc_short() methd
  tools/lib/lockdep: Remove private kernel headers
  tools/lib/lockdep: Hide liblockdep output from test results
  tools/lib/lockdep: Add dummy current_gfp_context()
  tools/include: Add IS_ERR_OR_NULL to err.h
  tools/lib/lockdep: Add empty __is_[module,kernel]_percpu_address
  tools/lib/lockdep: Include err.h
  tools/include: Add (mostly) empty include/linux/sched/mm.h
  tools/lib/lockdep: Use LDFLAGS
  tools/lib/lockdep: Remove double-quotes from soname
  tools/lib/lockdep: Fix object file paths used in an out-of-tree build
  tools/lib/lockdep: Fix compilation for 4.11
  tools/lib/lockdep: Don't mix fd-based and stream IO
  ...
2017-07-03 12:14:18 -07:00
Jason A. Donenfeld d06bfd1989 random: warn when kernel uses unseeded randomness
This enables an important dmesg notification about when drivers have
used the crng without it being seeded first. Prior, these errors would
occur silently, and so there hasn't been a great way of diagnosing these
types of bugs for obscure setups. By adding this as a config option, we
can leave it on by default, so that we learn where these issues happen,
in the field, will still allowing some people to turn it off, if they
really know what they're doing and do not want the log entries.

However, we don't leave it _completely_ by default. An earlier version
of this patch simply had `default y`. I'd really love that, but it turns
out, this problem with unseeded randomness being used is really quite
present and is going to take a long time to fix. Thus, as a compromise
between log-messages-for-all and nobody-knows, this is `default y`,
except it is also `depends on DEBUG_KERNEL`. This will ensure that the
curious see the messages while others don't have to.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-06-19 22:06:28 -04:00
Paul E. McKenney 43a0a2a7d7 rcu: Move RCU debug Kconfig options to kernel/rcu
RCU's debugging Kconfig options are in the unintuitive location
lib/Kconfig.debug, and there are enough of them that it would be good for
them to be more centralized.  This commit therefore extracts RCU's Kconfig
options from init/Kconfig into a new kernel/rcu/Kconfig.debug file.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-06-08 18:52:44 -07:00
Paul E. McKenney ae91aa0adb rcu: Remove debugfs tracing
RCU's debugfs tracing used to be the only reasonable low-level debug
information available, but ftrace and event tracing has since surpassed
the RCU debugfs level of usefulness.  This commit therefore removes
RCU's debugfs tracing.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-06-08 18:52:43 -07:00
Paul E. McKenney 41a2901e7d rcu: Remove SPARSE_RCU_POINTER Kconfig option
The sparse-based checking for non-RCU accesses to RCU-protected pointers
has been around for a very long time, and it is now the only type of
sparse-based checking that is optional.  This commit therefore makes
it unconditional.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
2017-06-08 18:52:41 -07:00