Pull powerpc fixes from Michael Ellerman:
 "Fixes marked for stable:
   - Convert cmp to cmpd in idle enter sequence (Segher Boessenkool)
   - cxl: Fix leaking pid refs in some error paths (Vaibhav Jain)
   - Re-fix race condition between going idle and entering guest (Paul Mackerras)
   - Fix race condition in setting lock bit in idle/wakeup code (Paul Mackerras)
   - radix: Use tlbiel only if we ever ran on the current cpu (Aneesh Kumar K.V)
   - relocation, register save fixes for system reset interrupt (Nicholas Piggin)

  Fixes for code merged this cycle:
   - Fix CONFIG_ALIVEC typo in restore_tm_state() (Valentin Rothberg)
   - KVM: PPC: Book3S HV: Fix build error when SMP=n (Michael Ellerman)"

* tag 'powerpc-4.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s: relocation, register save fixes for system reset interrupt
  powerpc/mm/radix: Use tlbiel only if we ever ran on the current cpu
  powerpc/process: Fix CONFIG_ALIVEC typo in restore_tm_state()
  powerpc/64: Fix race condition in setting lock bit in idle/wakeup code
  powerpc/64: Re-fix race condition between going idle and entering guest
  cxl: Fix leaking pid refs in some error paths
  powerpc: Convert cmp to cmpd in idle enter sequence
  KVM: PPC: Book3S HV: Fix build error when SMP=n

Pull perf fixes from Ingo Molnar:
 "Misc kernel fixes: a virtualization environment related fix, an uncore
  PMU driver removal handling fix, a PowerPC fix and new events for
  Knights Landing"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Honour the CPUID for number of fixed counters in hypervisors
  perf/powerpc: Don't call perf_event_disable() from atomic context
  perf/core: Protect PMU device removal with a 'pmu_bus_running' check, to fix CONFIG_DEBUG_TEST_DRIVER_REMOVE=y kernel panic
  perf/x86/intel/cstate: Add C-state residency events for Knights Landing

Pull libnvdimm fixes from Dan Williams:
 "A build fix, a NULL de-reference found by static analysis, a misuse of
  the percpu_ref_exit() (tagged for -stable), and notification of failed
  attempts to clear media errors.

  These patches have received a build success notification from the
  0day- kbuild-robot and appeared in next-20161028"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  device-dax: fix percpu_ref_exit ordering
  nvdimm: make CONFIG_NVDIMM_DAX 'bool'
  pmem: report error on clear poison failure
  libnvdimm, namespace: potential NULL deref on allocation error

Pull arm64 fixes from Will Deacon:
 "Three arm64 fixes for -rc3.  They're all pretty straightforward: a
  couple of NUMA issues from the Huawei folks and a thinko in
  __page_to_voff that seems to be benign, but is certainly better off
  fixed.

  Summary:
   - couple of NUMA fixes
   - thinko in __page_to_voff"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: mm: fix __page_to_voff definition
  arm64/numa: fix incorrect log for memory-less node
  arm64/numa: fix pcpu_cpu_distance() to get correct CPU proximity

Pull x86 fixes from Ingo Molnar:
 "Misc fixes: three build fixes, an unwinder fix and a microcode loader
  fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode/AMD: Fix more fallout from CONFIG_RANDOMIZE_MEMORY=y
  x86: Fix export for mcount and __fentry__
  x86/quirks: Hide maybe-uninitialized warning
  x86/build: Fix build with older GCC versions
  x86/unwind: Fix empty stack dereference in guess unwinder

Pull timer fixes from Ingo Molnar:
 "Fix four timer locking races: two were noticed by Linus while
  reviewing the code while chasing for a corruption bug, and two
  from fixing spurious USB timeouts"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers: Prevent base clock corruption when forwarding
  timers: Prevent base clock rewind when forwarding clock
  timers: Lock base for same bucket optimization
  timers: Plug locking race vs. timer migration

Merge branches 'core-urgent-for-linus', 'irq-urgent-for-linus' and 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool, irq and scheduler fixes from Ingo Molnar:
 "One more objtool fixlet for GCC6 code generation patterns, an irq
  DocBook fix and an unused variable warning fix in the scheduler"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix rare switch jump table pattern detection

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  doc: Add missing parameter for msi_setup

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Remove unused but set variable 'rq'

Pull btrfs fixes from Chris Mason:
 "My patch fixes the btrfs list_head abuse that we tracked down during
  Dave Jones' memory corruption investigation. With both Jens and my
  patches in place, I'm no longer able to trigger problems.

  Filipe is fixing a difficult old bug between snapshots, balance and
  send. Dave is cooking a few more for the next rc, but these are tested
  and ready"

* 'for-linus-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: fix races on root_log_ctx lists
  btrfs: fix incremental send failure caused by balance

Pull sound fixes from Takashi Iwai:
 "This contains the usual stuff -- the fixups and quirks for HD-audio
  and USB-audio, in addition to a bad regression fix in ALSA sequencer
  timer since 4.8, and a trivial fix for asihpi PCI driver"

* tag 'sound-4.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Add quirk for Syntek STK1160
  ALSA: seq: Fix time account regression
  ALSA: hda - Fix surround output pins for ASRock B150M mobo
  ALSA: hda - Fix headset mic detection problem for two Dell laptops
  ALSA: asihpi: fix kernel memory disclosure
  ALSA: hda - Adding a new group of pin cfg into ALC295 pin quirk table
  ALSA: hda - allow 40 bit DMA mask for NVidia devices

Pull drm x86/pat regression fixes from Dave Airlie:
 "This is a standalone pull request for the fix for a regression
  introduced in -rc1 by a change to vm_insert_mixed to start using the
  PAT range tracking to validate page protections. With this fix in
  place, all the VRAM mappings for GPU drivers ended up at UC instead of
  WC.

  There are probably better ways to fix this long term, but nothing I'd
  considered for -fixes that wouldn't need more settling in time. So
  I've just created a new arch API that the drivers can reserve all
  their VRAM aperture ranges as WC"

* tag 'drm-x86-pat-regression-fix' of git://people.freedesktop.org/~airlied/linux:
  drm/drivers: add support for using the arch wc mapping API.
  x86/io: add interface to reserve io memtype for a resource range. (v1.1)

Pull device mapper fixes from Mike Snitzer:

 - a couple DM raid and DM mirror fixes

 - a couple .request_fn request-based DM NULL pointer fixes

 - a fix for a DM target reference count leak, on target load error,
   that prevented associated DM target kernel module(s) from being
   removed

* tag 'dm-4.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm table: fix missing dm_put_target_type() in dm_table_add_target()
  dm rq: clear kworker_task if kthread_run() returned an error
  dm: free io_barrier after blk_cleanup_queue call
  dm raid: fix activation of existing raid4/10 devices
  dm mirror: use all available legs on multiple failures
  dm mirror: fix read error on recovery after default leg failure
  dm raid: fix compat_features validation

Pull key fixes from James Morris:

 - fix a buffer overflow when displaying /proc/keys [CVE-2016-7042].

 - fix broken initialisation in the big_key implementation that can
   result in an oops.

 - make big_key depend on having a random number generator available in
   Kconfig.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  security/keys: make BIG_KEYS dependent on stdrng.
  KEYS: Sort out big_key initialisation
  KEYS: Fix short sprintf buffer in /proc/keys show function

perf doesn't seem to honour the number of fixed counters specified by CPUID
leaf 0xa. It always assumes that Intel CPUs have at least 3 fixed counters.

So if some of the fixed counters are masked out by the hypervisor, it still
tries to check/set them.

This patch makes perf behave nicer when the kernel is running under a
hypervisor that doesn't expose all the counters.

This patch contains some ideas from Matt Wilson.
Signed-off-by: Imre Palik <imrep@amazon.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Alexander Kozyrev <alexander.kozyrev@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Artyom Kuanbekov <artyom.kuanbekov@intel.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Wilson <msw@amazon.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1477037939-15605-1-git-send-email-imrep.amz@gmail.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

The trinity syscall fuzzer triggered following WARN() on powerpc:

  WARNING: CPU: 9 PID: 2998 at arch/powerpc/kernel/hw_breakpoint.c:278
  ...
  NIP [c00000000093aedc] .hw_breakpoint_handler+0x28c/0x2b0
  LR [c00000000093aed8] .hw_breakpoint_handler+0x288/0x2b0
  Call Trace:
  [c0000002f7933580] [c00000000093aed8] .hw_breakpoint_handler+0x288/0x2b0 (unreliable)
  [c0000002f7933630] [c0000000000f671c] .notifier_call_chain+0x7c/0xf0
  [c0000002f79336d0] [c0000000000f6abc] .__atomic_notifier_call_chain+0xbc/0x1c0
  [c0000002f7933780] [c0000000000f6c40] .notify_die+0x70/0xd0
  [c0000002f7933820] [c00000000001a74c] .do_break+0x4c/0x100
  [c0000002f7933920] [c0000000000089fc] handle_dabr_fault+0x14/0x48

Followed by a lockdep warning:

  ===============================
  [ INFO: suspicious RCU usage. ]
  4.8.0-rc5+ #7 Tainted: G        W
  -------------------------------
  ./include/linux/rcupdate.h:556 Illegal context switch in RCU read-side critical section!

  other info that might help us debug this:

  rcu_scheduler_active = 1, debug_locks = 0
  2 locks held by ls/2998:
   #0:  (rcu_read_lock){......}, at: [<c0000000000f6a00>] .__atomic_notifier_call_chain+0x0/0x1c0
   #1:  (rcu_read_lock){......}, at: [<c00000000093ac50>] .hw_breakpoint_handler+0x0/0x2b0

  stack backtrace:
  CPU: 9 PID: 2998 Comm: ls Tainted: G        W       4.8.0-rc5+ #7
  Call Trace:
  [c0000002f7933150] [c00000000094b1f8] .dump_stack+0xe0/0x14c (unreliable)
  [c0000002f79331e0] [c00000000013c468] .lockdep_rcu_suspicious+0x138/0x180
  [c0000002f7933270] [c0000000001005d8] .___might_sleep+0x278/0x2e0
  [c0000002f7933300] [c000000000935584] .mutex_lock_nested+0x64/0x5a0
  [c0000002f7933410] [c00000000023084c] .perf_event_ctx_lock_nested+0x16c/0x380
  [c0000002f7933500] [c000000000230a80] .perf_event_disable+0x20/0x60
  [c0000002f7933580] [c00000000093aeec] .hw_breakpoint_handler+0x29c/0x2b0
  [c0000002f7933630] [c0000000000f671c] .notifier_call_chain+0x7c/0xf0
  [c0000002f79336d0] [c0000000000f6abc] .__atomic_notifier_call_chain+0xbc/0x1c0
  [c0000002f7933780] [c0000000000f6c40] .notify_die+0x70/0xd0
  [c0000002f7933820] [c00000000001a74c] .do_break+0x4c/0x100
  [c0000002f7933920] [c0000000000089fc] handle_dabr_fault+0x14/0x48

While it looks like the first WARN() is probably valid, the other one is
triggered by disabling event via perf_event_disable() from atomic context.

The event is disabled here in case we were not able to emulate
the instruction that hit the breakpoint. By disabling the event
we unschedule the event and make sure it's not scheduled back.

But we can't call perf_event_disable() from atomic context, instead
we need to use the event's pending_disable irq_work method to disable it.
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161026094824.GA21397@kravaSigned-off-by: Ingo Molnar <mingo@kernel.org>

perf/core: Protect PMU device removal with a 'pmu_bus_running' check, to fix CONFIG_DEBUG_TEST_DRIVER_REMOVE=y kernel panic

CAI Qian reported a crash in the PMU uncore device removal code,
enabled by the CONFIG_DEBUG_TEST_DRIVER_REMOVE=y option:

  https://marc.info/?l=linux-kernel&m=147688837328451

The reason for the crash is that perf_pmu_unregister() tries to remove
a PMU device which is not added at this point. We add PMU devices
only after pmu_bus is registered, which happens in the
perf_event_sysfs_init() call and sets the 'pmu_bus_running' flag.

The fix is to get the 'pmu_bus_running' flag state at the point
the PMU is taken out of the PMU list and remove the device
later only if it's set.
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161020111011.GA13361@kravaSigned-off-by: Ingo Molnar <mingo@kernel.org>

We needed the physical address of the container in order to compute the
offset within the relocated ramdisk. And we did this by doing __pa() on
the virtual address.

However, __pa() does checks whether the physical address is within
PAGE_OFFSET and __START_KERNEL_map - see __phys_addr() - which fail
if we have CONFIG_RANDOMIZE_MEMORY enabled: we feed a virtual address
which *doesn't* have the randomization offset into a function which uses
PAGE_OFFSET which *does* have that offset.

This makes this check fire:

	VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x));
			^^^^^^

due to the randomization offset.

The fix is as simple as using __pa_nodebug() because we do that
randomization offset accounting later in that function ourselves.
Reported-by: Bob Peterson <rpeterso@redhat.com>
Tested-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm <linux-mm@kvack.org>
Cc: stable@vger.kernel.org # 4.9
Link: http://lkml.kernel.org/r/20161027123623.j2jri5bandimboff@pd.tnicSigned-off-by: Ingo Molnar <mingo@kernel.org>

Merge misc fixes from Andrew Morton:
 "20 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  drivers/misc/sgi-gru/grumain.c: remove bogus 0x prefix from printk
  cris/arch-v32: cryptocop: print a hex number after a 0x prefix
  ipack: print a hex number after a 0x prefix
  block: DAC960: print a hex number after a 0x prefix
  fs: exofs: print a hex number after a 0x prefix
  lib/genalloc.c: start search from start of chunk
  mm: memcontrol: do not recurse in direct reclaim
  CREDITS: update credit information for Martin Kepplinger
  proc: fix NULL dereference when reading /proc/<pid>/auxv
  mm: kmemleak: ensure that the task stack is not freed during scanning
  lib/stackdepot.c: bump stackdepot capacity from 16MB to 128MB
  latent_entropy: raise CONFIG_FRAME_WARN by default
  kconfig.h: remove config_enabled() macro
  ipc: account for kmem usage on mqueue and msg
  mm/slab: improve performance of gathering slabinfo stats
  mm: page_alloc: use KERN_CONT where appropriate
  mm/list_lru.c: avoid error-path NULL pointer deref
  h8300: fix syscall restarting
  kcov: properly check if we are in an interrupt
  mm/slab: fix kmemcg cache creation delayed issue

Would like to have this be a decimal number.

Link: http://lkml.kernel.org/r/20161026134746.GA30169@sgi.comSigned-off-by: Dimitri Sivanich <sivanich@sgi.com>
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It makes the result hard to interpret correctly if a base 10 number is
prefixed by 0x.  So change to a hex number.

Link: http://lkml.kernel.org/r/20161026125658.25728-6-u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It makes the result hard to interpret correctly if a base 10 number is
prefixed by 0x.  So change to a hex number.

Link: http://lkml.kernel.org/r/20161026125658.25728-4-u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Cc: Jens Taprogge <jens.taprogge@taprogge.org>
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>

It makes the message hard to interpret correctly if a base 10 number is
prefixed by 0x.  So change to a hex number.

Link: http://lkml.kernel.org/r/20161026125658.25728-3-u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It makes the message hard to interpret correctly if a base 10 number is
prefixed by 0x.  So change to a hex number.

Link: http://lkml.kernel.org/r/20161026125658.25728-2-u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Boaz Harrosh <ooo@electrozaur.com>
Cc: Benny Halevy <bhalevy@primarydata.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

gen_pool_alloc_algo() iterates over the chunks of a pool trying to find
a contiguous block of memory that satisfies the allocation request.

The shortcut

	if (size > atomic_read(&chunk->avail))
		continue;

makes the loop skip over chunks that do not have enough bytes left to
fulfill the request.  There are two situations, though, where an
allocation might still fail:

(1) The available memory is not contiguous, i.e.  the request cannot
    be fulfilled due to external fragmentation.

(2) A race condition.  Another thread runs the same code concurrently
    and is quicker to grab the available memory.

In those situations, the loop calls pool->algo() to search the entire
chunk, and pool->algo() returns some value that is >= end_bit to
indicate that the search failed.  This return value is then assigned to
start_bit.  The variables start_bit and end_bit describe the range that
should be searched, and this range should be reset for every chunk that
is searched.  Today, the code fails to reset start_bit to 0.  As a
result, prefixes of subsequent chunks are ignored.  Memory allocations
might fail even though there is plenty of room left in these prefixes of
those other chunks.

Fixes: 7f184275 ("lib, Make gen_pool memory allocator lockless")
Link: http://lkml.kernel.org/r/1477420604-28918-1-git-send-email-danielmentz@google.comSigned-off-by: Daniel Mentz <danielmentz@google.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On 4.0, we saw a stack corruption from a page fault entering direct
memory cgroup reclaim, calling into btrfs_releasepage(), which then
tried to allocate an extent and recursed back into a kmem charge ad
nauseam:

  [...]
  btrfs_releasepage+0x2c/0x30
  try_to_release_page+0x32/0x50
  shrink_page_list+0x6da/0x7a0
  shrink_inactive_list+0x1e5/0x510
  shrink_lruvec+0x605/0x7f0
  shrink_zone+0xee/0x320
  do_try_to_free_pages+0x174/0x440
  try_to_free_mem_cgroup_pages+0xa7/0x130
  try_charge+0x17b/0x830
  memcg_charge_kmem+0x40/0x80
  new_slab+0x2d9/0x5a0
  __slab_alloc+0x2fd/0x44f
  kmem_cache_alloc+0x193/0x1e0
  alloc_extent_state+0x21/0xc0
  __clear_extent_bit+0x2b5/0x400
  try_release_extent_mapping+0x1a3/0x220
  __btrfs_releasepage+0x31/0x70
  btrfs_releasepage+0x2c/0x30
  try_to_release_page+0x32/0x50
  shrink_page_list+0x6da/0x7a0
  shrink_inactive_list+0x1e5/0x510
  shrink_lruvec+0x605/0x7f0
  shrink_zone+0xee/0x320
  do_try_to_free_pages+0x174/0x440
  try_to_free_mem_cgroup_pages+0xa7/0x130
  try_charge+0x17b/0x830
  mem_cgroup_try_charge+0x65/0x1c0
  handle_mm_fault+0x117f/0x1510
  __do_page_fault+0x177/0x420
  do_page_fault+0xc/0x10
  page_fault+0x22/0x30

On later kernels, kmem charging is opt-in rather than opt-out, and that
particular kmem allocation in btrfs_releasepage() is no longer being
charged and won't recurse and overrun the stack anymore.

But it's not impossible for an accounted allocation to happen from the
memcg direct reclaim context, and we needed to reproduce this crash many
times before we even got a useful stack trace out of it.

Like other direct reclaimers, mark tasks in memcg reclaim PF_MEMALLOC to
avoid recursing into any other form of direct reclaim.  Then let
recursive charges from PF_MEMALLOC contexts bypass the cgroup limit.

Link: http://lkml.kernel.org/r/20161025141050.GA13019@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Content and employer changed.

Link: http://lkml.kernel.org/r/1477304102-28830-1-git-send-email-martin.kepplinger@ginzinger.comSigned-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Reading auxv of any kernel thread results in NULL pointer dereferencing
in auxv_read() where mm can be NULL.  Fix that by checking for NULL mm
and bailing out early.  This is also the original behavior changed by
recent commit c5317167 ("proc: switch auxv to use of __mem_open()").

  # cat /proc/2/auxv
  Unable to handle kernel NULL pointer dereference at virtual address 000000a8
  Internal error: Oops: 17 [#1] PREEMPT SMP ARM
  CPU: 3 PID: 113 Comm: cat Not tainted 4.9.0-rc1-ARCH+ #1
  Hardware name: BCM2709
  task: ea3b0b00 task.stack: e99b2000
  PC is at auxv_read+0x24/0x4c
  LR is at do_readv_writev+0x2fc/0x37c
  Process cat (pid: 113, stack limit = 0xe99b2210)
  Call chain:
    auxv_read
    do_readv_writev
    vfs_readv
    default_file_splice_read
    splice_direct_to_actor
    do_splice_direct
    do_sendfile
    SyS_sendfile64
    ret_fast_syscall

Fixes: c5317167 ("proc: switch auxv to use of __mem_open()")
Link: http://lkml.kernel.org/r/1476966200-14457-1-git-send-email-chianglungyu@gmail.comSigned-off-by: Leon Yu <chianglungyu@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Janis Danisevskis <jdanis@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 68f24b08 ("sched/core: Free the stack early if
CONFIG_THREAD_INFO_IN_TASK") may cause the task->stack to be freed
during kmemleak_scan() execution, leading to either a NULL pointer fault
(if task->stack is NULL) or kmemleak accessing already freed memory.

This patch uses the new try_get_task_stack() API to ensure that the task
stack is not freed during kmemleak stack scanning.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=173901.

Fixes: 68f24b08 ("sched/core: Free the stack early if CONFIG_THREAD_INFO_IN_TASK")
Link: http://lkml.kernel.org/r/1476266223-14325-1-git-send-email-catalin.marinas@arm.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: CAI Qian <caiqian@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KASAN uses stackdepot to memorize stacks for all kmalloc/kfree calls.
Current stackdepot capacity is 16MB (1024 top level entries x 4 pages on
second level).  Size of each stack is (num_frames + 3) * sizeof(long).
Which gives us ~84K stacks.  This capacity was chosen empirically and it
is enough to run kernel normally.

However, when lots of configs are enabled and a fuzzer tries to maximize
code coverage, it easily hits the limit within tens of minutes.  I've
tested for long a time with number of top level entries bumped 4x
(4096).  And I think I've seen overflow only once.  But I don't have all
configs enabled and code coverage has not reached maximum yet.  So bump
it 8x to 8192.

Since we have two-level table, memory cost of this is very moderate --
currently the top-level table is 8KB, with this patch it is 64KB, which
is negligible under KASAN.

Here is some approx math.

128MB allows us to memorize ~670K stacks (assuming stack is ~200b).
I've grepped kernel for kmalloc|kfree|kmem_cache_alloc|kmem_cache_free|
kzalloc|kstrdup|kstrndup|kmemdup and it gives ~60K matches.  Most of
alloc/free call sites are reachable with only one stack.  But some
utility functions can have large fanout.  Assuming average fanout is 5x,
total number of alloc/free stacks is ~300K.

Link: http://lkml.kernel.org/r/1476458416-122131-1-git-send-email-dvyukov@google.comSigned-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When building with the latent_entropy plugin, set the default
CONFIG_FRAME_WARN to 2048, since some __init functions have many basic
blocks that, when instrumented by the latent_entropy plugin, grow beyond
1024 byte stack size on 32-bit builds.

Link: http://lkml.kernel.org/r/20161018211216.GA39687@beastSigned-off-by: Kees Cook <keescook@chromium.org>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Cc: Dmitry Vyukov <dvyukov@google.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>

The use of config_enabled() is ambiguous.  For config options,
IS_ENABLED(), IS_REACHABLE(), etc.  will make intention clearer.
Sometimes config_enabled() has been used for non-config options because
it is useful to check whether the given symbol is defined or not.

I have been tackling on deprecating config_enabled(), and now is the
time to finish this work.

Some new users have appeared for v4.9-rc1, but it is trivial to replace
them:

 - arch/x86/mm/kaslr.c
  replace config_enabled() with IS_ENABLED() because
  CONFIG_X86_ESPFIX64 and CONFIG_EFI are boolean.

 - include/asm-generic/export.h
  replace config_enabled() with __is_defined().

Then, config_enabled() can be removed now.

Going forward, please use IS_ENABLED(), IS_REACHABLE(), etc. for config
options, and __is_defined() for non-config symbols.

Link: http://lkml.kernel.org/r/1476616078-32252-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When kmem accounting switched from account by default to only account if
flagged by __GFP_ACCOUNT, IPC mqueue and messages was left out.

The production use case at hand is that mqueues should be customizable
via sysctls in Docker containers in a Kubernetes cluster.  This can only
be safely allowed to the users of the cluster (without the risk that
they can cause resource shortage on a node, influencing other users'
containers) if all resources they control are bounded, i.e.  accounted
for.

Link: http://lkml.kernel.org/r/1476806075-1210-1-git-send-email-arozansk@redhat.comSigned-off-by: Aristeu Rozanski <arozansk@redhat.com>
Reported-by: Stefan Schimanski <sttts@redhat.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Stefan Schimanski <sttts@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On large systems, when some slab caches grow to millions of objects (and
many gigabytes), running 'cat /proc/slabinfo' can take up to 1-2
seconds.  During this time, interrupts are disabled while walking the
slab lists (slabs_full, slabs_partial, and slabs_free) for each node,
and this sometimes causes timeouts in other drivers (for instance,
Infiniband).

This patch optimizes 'cat /proc/slabinfo' by maintaining a counter for
total number of allocated slabs per node, per cache.  This counter is
updated when a slab is created or destroyed.  This enables us to skip
traversing the slabs_full list while gathering slabinfo statistics, and
since slabs_full tends to be the biggest list when the cache is large,
it results in a dramatic performance improvement.  Getting slabinfo
statistics now only requires walking the slabs_free and slabs_partial
lists, and those lists are usually much smaller than slabs_full.

We tested this after growing the dentry cache to 70GB, and the
performance improved from 2s to 5ms.

Link: http://lkml.kernel.org/r/1472517876-26814-1-git-send-email-aruna.ramakrishna@oracle.comSigned-off-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Recent changes to printk require KERN_CONT uses to continue logging
messages.  So add KERN_CONT where necessary.

[akpm@linux-foundation.org: coding-style fixes]
Fixes: 4bcc595c ("printk: reinstate KERN_CONT for printing continuation lines")
Link: http://lkml.kernel.org/r/c7df37c8665134654a17aaeb8b9f6ace1d6db58b.1476239034.git.joe@perches.comReported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

As described in https://bugzilla.kernel.org/show_bug.cgi?id=177821:

After some analysis it seems to be that the problem is in alloc_super().
In case list_lru_init_memcg() fails it goes into destroy_super(), which
calls list_lru_destroy().

And in list_lru_init() we see that in case memcg_init_list_lru() fails,
lru->node is freed, but not set NULL, which then leads list_lru_destroy()
to believe it is initialized and call memcg_destroy_list_lru().
memcg_destroy_list_lru() in turn can access lru->node[i].memcg_lrus,
which is NULL.

[akpm@linux-foundation.org: add comment]
Signed-off-by: Alexander Polakov <apolyakov@beget.ru>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Back in commit f56141e3 ("all arches, signal: move restart_block to
struct task_struct"), all architectures and core code were changed to
use task_struct::restart_block.  However, when h8300 support was
subsequently restored in v4.2, it was not updated to account for this,
and maintains thread_info::restart_block, which is not kept in sync.

This patch drops the redundant restart_block from thread_info, and moves
h8300 to the common one in task_struct, ensuring that syscall restarting
always works as expected.

Fixes: f56141e3 ("all arches, signal: move restart_block to struct task_struct")
Link: http://lkml.kernel.org/r/1476714934-11635-1-git-send-email-mark.rutland@arm.comSigned-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
Cc: <stable@vger.kernel.org>	[4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

in_interrupt() returns a nonzero value when we are either in an
interrupt or have bh disabled via local_bh_disable().  Since we are
interested in only ignoring coverage from actual interrupts, do a proper
check instead of just calling in_interrupt().

As a result of this change, kcov will start to collect coverage from
within local_bh_disable()/local_bh_enable() sections.

Link: http://lkml.kernel.org/r/1476115803-20712-1-git-send-email-andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Nicolai Stange <nicstange@gmail.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: James Morse <james.morse@arm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is a bug report that SLAB makes extreme load average due to over
2000 kworker thread.

  https://bugzilla.kernel.org/show_bug.cgi?id=172981

This issue is caused by kmemcg feature that try to create new set of
kmem_caches for each memcg.  Recently, kmem_cache creation is slowed by
synchronize_sched() and futher kmem_cache creation is also delayed since
kmem_cache creation is synchronized by a global slab_mutex lock.  So,
the number of kworker that try to create kmem_cache increases quietly.

synchronize_sched() is for lockless access to node's shared array but
it's not needed when a new kmem_cache is created.  So, this patch rules
out that case.

Fixes: 801faf0d ("mm/slab: lockless decision to grow cache")
Link: http://lkml.kernel.org/r/1475734855-4837-1-git-send-email-iamjoonsoo.kim@lge.comReported-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@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>

We need to wait until the percpu_ref is released before exit. Otherwise,
we sometimes lose the race and trigger this new warning that was added
in v4.9 (commit a67823c1 "percpu-refcount: init ->confirm_switch
member properly"):

 WARNING: CPU: 0 PID: 3629 at lib/percpu-refcount.c:107 percpu_ref_exit+0x51/0x60
 [..]
 Call Trace:
  [<ffffffff814bf093>] dump_stack+0x85/0xc2
  [<ffffffff810b15db>] __warn+0xcb/0xf0
  [<ffffffff810b170d>] warn_slowpath_null+0x1d/0x20
  [<ffffffff814d70c1>] percpu_ref_exit+0x51/0x60
  [<ffffffffa005706a>] dax_pmem_percpu_exit+0x1a/0x50 [dax_pmem]
  [<ffffffff81615f1f>] devm_action_release+0xf/0x20

Cc: <stable@vger.kernel.org>
Fixes: ab68f262 ("/dev/dax, pmem: direct access to persistent memory")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

No, KASAN may not be able to co-exist with HOTPLUG_MEMORY at runtime,
but for build testing there is no reason not to allow them together.

This hopefully means better build coverage and fewer embarrasing silly
problems like the one fixed by commit 9db4f36e ("mm: remove unused
variable in memory hotplug") in the future.

Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

A bugfix just tried to address a randconfig build problem and introduced
a variant of the same problem: with CONFIG_LIBNVDIMM=y and
CONFIG_NVDIMM_DAX=m, the nvdimm module now fails to link:

drivers/nvdimm/built-in.o: In function `to_nd_device_type':
bus.c:(.text+0x1b5d): undefined reference to `is_nd_dax'
drivers/nvdimm/built-in.o: In function `nd_region_notify_driver_action.constprop.2':
region_devs.c:(.text+0x6b6c): undefined reference to `is_nd_dax'
region_devs.c:(.text+0x6b8c): undefined reference to `to_nd_dax'
drivers/nvdimm/built-in.o: In function `nd_region_probe':
region.c:(.text+0x70f3): undefined reference to `nd_dax_create'
drivers/nvdimm/built-in.o: In function `mode_show':
namespace_devs.c:(.text+0xa196): undefined reference to `is_nd_dax'
drivers/nvdimm/built-in.o: In function `nvdimm_namespace_common_probe':
(.text+0xa55f): undefined reference to `is_nd_dax'
drivers/nvdimm/built-in.o: In function `nvdimm_namespace_common_probe':
(.text+0xa56e): undefined reference to `to_nd_dax'

This reverts the earlier fix, making NVDIMM_DAX a 'bool' option again
as it should be (it gets linked into the libnvdimm module). To fix
the original problem, I'm adding a dependency on LIBNVDIMM to
DEV_DAX_PMEM, which ensures we can't have that one built-in if the
rest is a module.

Fixes: 4e65e938 ("/dev/dax: fix Kconfig dependency build breakage")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>