It adds support for new Mellanox system types of basic class msn274x,
containing system MSN2740 (32x100GbE Ethernet switch with cost reduction)
and its derivatives. These are the Top of the Rack system, equipped with
Mellanox Small Form Factor carrier board and switch board with Mellanox
Spectrum device, which supports Ethernet switching with 32X100G ports line
rate of up to EDR speed.
Signed-off-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

Add dedicated structure with power cable setting for Mellanox msn21xx
family. These systems do not have a physical device for the power unit
controller. When the power cable is inserted or removed, the relevant
interrupt signal is handled, the status is updated, but no device is
associated with the signal.

Add definition for interrupt low aggregation signal. On system from
msn21xx family, low aggregation mask should be removed in order to allow
signal to hit CPU.

Fixes: 6613d18e ("platform/x86: mlx-platform: Move module from arch/x86")
Signed-off-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

Add define for the negative bus ID in order to use it in case no hotplug
device is associated with the hotplug interrupt signal. In this case,
the signal will be handled by the mlxreg-hotplug driver, but no device
will be associated with the signal.
Signed-off-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

Add defines for the bus IDs, used for hotplug device topology to improve
code readability. Defines added for FAN and power units.
Signed-off-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

With gcc-4.1.2:

    drivers/platform/mellanox/mlxreg-hotplug.c: In function ‘mlxreg_hotplug_health_work_helper’:
    drivers/platform/mellanox/mlxreg-hotplug.c:347: warning: ‘ret’ is used uninitialized in this function

Indeed, if mlxreg_core_item.count is zero, ret is used uninitialized.

While this is unlikely to happen (it is set to ARRAY_SIZE(...) in x86
board files), this is done in another source file, so fix this by
preinitializing ret to zero.

Fixes: c6acad68 ("platform/mellanox: mlxreg-hotplug: Modify to use a regmap interface")
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

...instead of open coding file operations followed by custom ->open()
callbacks per each attribute.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>

...instead of open coding file operations followed by custom ->open()
callbacks per each attribute.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>

...instead of open coding file operations followed by custom ->open()
callbacks per each attribute.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>

The DEFINE_SHOW_ATTRIBUTE() helper macro would be useful for current
users, which are many of them, and for new comers to decrease code
duplication.
Acked-by: NLee Jones <lee.jones@linaro.org>
Acked-by: NDarren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>

Merge misc updates from Andrew Morton:

 - kasan updates

 - procfs

 - lib/bitmap updates

 - other lib/ updates

 - checkpatch tweaks

 - rapidio

 - ubsan

 - pipe fixes and cleanups

 - lots of other misc bits

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (114 commits)
  Documentation/sysctl/user.txt: fix typo
  MAINTAINERS: update ARM/QUALCOMM SUPPORT patterns
  MAINTAINERS: update various PALM patterns
  MAINTAINERS: update "ARM/OXNAS platform support" patterns
  MAINTAINERS: update Cortina/Gemini patterns
  MAINTAINERS: remove ARM/CLKDEV SUPPORT file pattern
  MAINTAINERS: remove ANDROID ION pattern
  mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors
  mm: docs: fix parameter names mismatch
  mm: docs: fixup punctuation
  pipe: read buffer limits atomically
  pipe: simplify round_pipe_size()
  pipe: reject F_SETPIPE_SZ with size over UINT_MAX
  pipe: fix off-by-one error when checking buffer limits
  pipe: actually allow root to exceed the pipe buffer limits
  pipe, sysctl: remove pipe_proc_fn()
  pipe, sysctl: drop 'min' parameter from pipe-max-size converter
  kasan: rework Kconfig settings
  crash_dump: is_kdump_kernel can be boolean
  kernel/mutex: mutex_is_locked can be boolean
  ...

Pull scheduler updates from Ingo Molnar:

 - membarrier updates (Mathieu Desnoyers)

 - SMP balancing optimizations (Mel Gorman)

 - stats update optimizations (Peter Zijlstra)

 - RT scheduler race fixes (Steven Rostedt)

 - misc fixes and updates

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Use a recently used CPU as an idle candidate and the basis for SIS
  sched/fair: Do not migrate if the prev_cpu is idle
  sched/fair: Restructure wake_affine*() to return a CPU id
  sched/fair: Remove unnecessary parameters from wake_affine_idle()
  sched/rt: Make update_curr_rt() more accurate
  sched/rt: Up the root domain ref count when passing it around via IPIs
  sched/rt: Use container_of() to get root domain in rto_push_irq_work_func()
  sched/core: Optimize update_stats_*()
  sched/core: Optimize ttwu_stat()
  membarrier/selftest: Test private expedited sync core command
  membarrier/arm64: Provide core serializing command
  membarrier/x86: Provide core serializing command
  membarrier: Provide core serializing command, *_SYNC_CORE
  lockin/x86: Implement sync_core_before_usermode()
  locking: Introduce sync_core_before_usermode()
  membarrier/selftest: Test global expedited command
  membarrier: Provide GLOBAL_EXPEDITED command
  membarrier: Document scheduler barrier requirements
  powerpc, membarrier: Skip memory barrier in switch_mm()
  membarrier/selftest: Test private expedited command

Pull perf fixes from Ingo Molnar:
 "Tooling fixes, plus add missing interval sampling to certain x86 PEBS
  events"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Add trace/beauty/generated/ into .gitignore
  perf trace: Fix call-graph output
  x86/events/intel/ds: Add PERF_SAMPLE_PERIOD into PEBS_FREERUNNING_FLAGS
  perf record: Fix period option handling
  perf evsel: Fix period/freq terms setup
  tools headers: Synchoronize x86 features UAPI headers
  tools headers: Synchronize uapi/linux/sched.h
  tools headers: Sync {tools/,}arch/powerpc/include/uapi/asm/kvm.h
  tooling headers: Synchronize updated s390 kvm UAPI headers
  tools headers: Synchronize sound/asound.h

Pull locking fixlets from Ingo Molnar:
 "An endianness fix and a jump labels branch hint update"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/qrwlock: include asm/byteorder.h as needed
  jump_label: Add branch hints to static_branch_{un,}likely()

Pull networking fixes from David Miller:

 1) Fix error path in netdevsim, from Jakub Kicinski.

 2) Default values listed in tcp_wmem and tcp_rmem documentation were
    inaccurate, from Tonghao Zhang.

 3) Fix route leaks in SCTP, both for ipv4 and ipv6. From Alexey Kodanev
    and Tommi Rantala.

 4) Fix "MASK < Y" meant to be "MASK << Y" in xgbe driver, from Wolfram
    Sang.

 5) Use after free in u32_destroy_key(), from Paolo Abeni.

 6) Fix two TX issues in be2net driver, from Suredh Reddy.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (25 commits)
  be2net: Handle transmit completion errors in Lancer
  be2net: Fix HW stall issue in Lancer
  RDS: IB: Fix null pointer issue
  nfp: fix kdoc warnings on nested structures
  sample/bpf: fix erspan metadata
  net: erspan: fix erspan config overwrite
  net: erspan: fix metadata extraction
  cls_u32: fix use after free in u32_destroy_key()
  net: amd-xgbe: fix comparison to bitshift when dealing with a mask
  net: phy: Handle not having GPIO enabled in the kernel
  ibmvnic: fix empty firmware version and errors cleanup
  sctp: fix dst refcnt leak in sctp_v4_get_dst
  sctp: fix dst refcnt leak in sctp_v6_get_dst()
  dwc-xlgmac: remove Jie Deng as co-maintainer
  doc: Change the min default value of tcp_wmem/tcp_rmem.
  samples/bpf: use bpf_set_link_xdp_fd
  libbpf: add missing SPDX-License-Identifier
  libbpf: add error reporting in XDP
  libbpf: add function to setup XDP
  tools: add netlink.h and if_link.h in tools uapi
  ...

Fix 'documetation' to 'documentation'

Link: http://lkml.kernel.org/r/CAKW4uUxRPZz59aWAX8ytaCB5=Qh6d_CvAnO7rYq-6NRAnQJbDA@mail.gmail.comSigned-off-by: NKangmin Park <l4stpr0gr4m@gmail.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Jiri Kosina <trivial@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 32173741 ("tty: serial: msm: Move header file into driver")
removed the .h file, update the patterns.

Link: http://lkml.kernel.org/r/2b7478bc4c35ab3ac6b06b4edd3b645a8c34a4a2.1517147485.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 4c25c5d2 ("ARM: pxa: make more mach/*.h files local") moved
the files around, update the patterns.

Link: http://lkml.kernel.org/r/a291f6f61e378a1f35e266fe4c5f646b9feeaa6a.1517147485.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Tomas Cech <sleep_walker@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 9e6c62b0 ("ARM: dts: rename oxnas dts files") renamed the
files, update the patterns.

[akpm@linux-foundation.org: crunch into a single globbed term, per Arnd]
Link: http://lkml.kernel.org/r/b39d779e143b3c0a4e7dff827346e509447e3e8e.1517147485.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Daniel Golle <daniel@makrotopia.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 4d5ae32f ("net: ethernet: Add a driver for Gemini gigabit
ethernet") added invalid patterns.  Fix it.

Link: http://lkml.kernel.org/r/65b104609e0071d0fbe0dcce3a8e6138a4cf8c25.1517147485.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 34d2f4d3 ("ARM: Use generic clkdev.h header") removed the
file, remove the pattern.

Link: http://lkml.kernel.org/r/41bfff9449a5894b94f583983b6c6cb46f4cd821.1517147485.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The file drivers/staging/android/uapi/ion_test.h was removed by commit
9828282e ("staging: android: ion: Remove old platform support")

Remove the pattern.

Link: http://lkml.kernel.org/r/182debec22002c9a1de44e79a7441288942b205c.1517147485.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Acked-by: NLaura Abbott <labbott@redhat.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Link: http://lkml.kernel.org/r/1516700871-22279-4-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are several places where parameter descriptions do no match the
actual code.  Fix it.

Link: http://lkml.kernel.org/r/1516700871-22279-3-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

so that kernel-doc will properly recognize the parameter and function
descriptions.

Link: http://lkml.kernel.org/r/1516700871-22279-2-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The pipe buffer limits are accessed without any locking, and may be
changed at any time by the sysctl handlers.  In theory this could cause
problems for expressions like the following:

    pipe_user_pages_hard && user_bufs > pipe_user_pages_hard

...  since the assembly code might reference the 'pipe_user_pages_hard'
memory location multiple times, and if the admin removes the limit by
setting it to 0, there is a very brief window where processes could
incorrectly observe the limit to be exceeded.

Fix this by loading the limits with READ_ONCE() prior to use.

Link: http://lkml.kernel.org/r/20180111052902.14409-8-ebiggers3@gmail.comSigned-off-by: NEric Biggers <ebiggers@google.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NJoe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

round_pipe_size() calculates the number of pages the requested size
corresponds to, then rounds the page count up to the next power of 2.

However, it also rounds everything < PAGE_SIZE up to PAGE_SIZE.
Therefore, there's no need to actually translate the size into a page
count; we just need to round the size up to the next power of 2.

We do need to verify the size isn't greater than (1 << 31), since on
32-bit systems roundup_pow_of_two() would be undefined in that case.  But
that can just be combined with the UINT_MAX check which we need anyway
now.

Finally, update pipe_set_size() to not redundantly check the return value
of round_pipe_size() for the "invalid size" case twice.

Link: http://lkml.kernel.org/r/20180111052902.14409-7-ebiggers3@gmail.comSigned-off-by: NEric Biggers <ebiggers@google.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NJoe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A pipe's size is represented as an 'unsigned int'.  As expected, writing a
value greater than UINT_MAX to /proc/sys/fs/pipe-max-size fails with
EINVAL.  However, the F_SETPIPE_SZ fcntl silently truncates such values to
32 bits, rather than failing with EINVAL as expected.  (It *does* fail
with EINVAL for values above (1 << 31) but <= UINT_MAX.)

Fix this by moving the check against UINT_MAX into round_pipe_size() which
is called in both cases.

Link: http://lkml.kernel.org/r/20180111052902.14409-6-ebiggers3@gmail.comSigned-off-by: NEric Biggers <ebiggers@google.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NJoe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With pipe-user-pages-hard set to 'N', users were actually only allowed up
to 'N - 1' buffers; and likewise for pipe-user-pages-soft.

Fix this to allow up to 'N' buffers, as would be expected.

Link: http://lkml.kernel.org/r/20180111052902.14409-5-ebiggers3@gmail.com
Fixes: b0b91d18 ("pipe: fix limit checking in pipe_set_size()")
Signed-off-by: NEric Biggers <ebiggers@google.com>
Acked-by: NWilly Tarreau <w@1wt.eu>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NJoe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

pipe-user-pages-hard and pipe-user-pages-soft are only supposed to apply
to unprivileged users, as documented in both Documentation/sysctl/fs.txt
and the pipe(7) man page.

However, the capabilities are actually only checked when increasing a
pipe's size using F_SETPIPE_SZ, not when creating a new pipe.  Therefore,
if pipe-user-pages-hard has been set, the root user can run into it and be
unable to create pipes.  Similarly, if pipe-user-pages-soft has been set,
the root user can run into it and have their pipes limited to 1 page each.

Fix this by allowing the privileged override in both cases.

Link: http://lkml.kernel.org/r/20180111052902.14409-4-ebiggers3@gmail.com
Fixes: 759c0114 ("pipe: limit the per-user amount of pages allocated in pipes")
Signed-off-by: NEric Biggers <ebiggers@google.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NJoe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

pipe_proc_fn() is no longer needed, as it only calls through to
proc_dopipe_max_size().  Just put proc_dopipe_max_size() in the ctl_table
entry directly, and remove the unneeded EXPORT_SYMBOL() and the ENOSYS
stub for it.

(The reason the ENOSYS stub isn't needed is that the pipe-max-size
ctl_table entry is located directly in 'kern_table' rather than being
registered separately.  Therefore, the entry is already only defined when
the kernel is built with sysctl support.)

Link: http://lkml.kernel.org/r/20180111052902.14409-3-ebiggers3@gmail.comSigned-off-by: NEric Biggers <ebiggers@google.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NJoe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "pipe: buffer limits fixes and cleanups", v2.

This series simplifies the sysctl handler for pipe-max-size and fixes
another set of bugs related to the pipe buffer limits:

- The root user wasn't allowed to exceed the limits when creating new
  pipes.

- There was an off-by-one error when checking the limits, so a limit of
  N was actually treated as N - 1.

- F_SETPIPE_SZ accepted values over UINT_MAX.

- Reading the pipe buffer limits could be racy.

This patch (of 7):

Before validating the given value against pipe_min_size,
do_proc_dopipe_max_size_conv() calls round_pipe_size(), which rounds the
value up to pipe_min_size.  Therefore, the second check against
pipe_min_size is redundant.  Remove it.

Link: http://lkml.kernel.org/r/20180111052902.14409-2-ebiggers3@gmail.comSigned-off-by: NEric Biggers <ebiggers@google.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NJoe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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 3f181b4d ("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:
  3cd890db ("media: dvb-frontends: fix i2c access helpers for KASAN")
  16c3ada8 ("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 c5caf21a.  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 3f181b4d ("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.deSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NAndrey 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make is_kdump_kernel return bool due to this particular function only
using either one or zero as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1513308799-19232-8-git-send-email-baiyaowei@cmss.chinamobile.comSigned-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make mutex_is_locked return bool due to this particular function only
using either one or zero as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1513266622-15860-7-git-send-email-baiyaowei@cmss.chinamobile.comSigned-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make module_is_live return bool due to this particular function only using
either one or zero as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1513266622-15860-6-git-send-email-baiyaowei@cmss.chinamobile.comSigned-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make iomem_is_exclusive return bool due to this particular function only
using either one or zero as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1513266622-15860-5-git-send-email-baiyaowei@cmss.chinamobile.comSigned-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make current_cpuset_is_being_rebound return bool due to this particular
function only using either one or zero as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1513266622-15860-4-git-send-email-baiyaowei@cmss.chinamobile.comSigned-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make __lockref_is_dead return bool due to this function only using either
true or false as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1513266622-15860-3-git-send-email-baiyaowei@cmss.chinamobile.comSigned-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make memblock_is_map/region_memory return bool due to these two
functions only using either true or false as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1513266622-15860-2-git-send-email-baiyaowei@cmss.chinamobile.comSigned-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The file was converted from print_symbol() to %pf some time ago in
commit ef26f20c ("genirq: Print threaded handler in spurious debug
output").  kallsyms does not seem to be needed anymore.

Link: http://lkml.kernel.org/r/20171208025616.16267-10-sergey.senozhatsky@gmail.comSigned-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>