The introduction of switch_mm_irqs_off() brought back an old bug
regarding the use of preempt_enable_no_resched:

As part of:

  62b94a08 ("sched/preempt: Take away preempt_enable_no_resched() from modules")

the definition of preempt_enable_no_resched() is only available in
built-in code, not in loadable modules, so we can't generally use
it from header files.

However, the ARM version of finish_arch_post_lock_switch()
calls preempt_enable_no_resched() and is defined as a static
inline function in asm/mmu_context.h. This in turn means we cannot
include asm/mmu_context.h from modules.

With today's tip tree, asm/mmu_context.h gets included from
linux/mmu_context.h, which is normally the exact pattern one would
expect, but unfortunately, linux/mmu_context.h can be included from
the vhost driver that is a loadable module, now causing this compile
time error with modular configs:

  In file included from ../include/linux/mmu_context.h:4:0,
                   from ../drivers/vhost/vhost.c:18:
  ../arch/arm/include/asm/mmu_context.h: In function 'finish_arch_post_lock_switch':
  ../arch/arm/include/asm/mmu_context.h:88:3: error: implicit declaration of function 'preempt_enable_no_resched' [-Werror=implicit-function-declaration]
     preempt_enable_no_resched();

Andy already tried to fix the bug by including linux/preempt.h
from asm/mmu_context.h, but that didn't help. Arnd suggested reordering
the header files, which wasn't popular, so let's use this
workaround instead:

The finish_arch_post_lock_switch() definition is now also hidden
inside of #ifdef MODULE, so we don't see anything referencing
preempt_enable_no_resched() from a header file. I've built a
few hundred randconfig kernels with this, and did not see any
new problems.
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-arm-kernel@lists.infradead.org
Fixes: f98db601 ("sched/core: Add switch_mm_irqs_off() and use it in the scheduler")
Link: http://lkml.kernel.org/r/1463146234-161304-1-git-send-email-arnd@arndb.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

tsk_nr_cpus_allowed() is an accessor for task->nr_cpus_allowed which allows
us to change the representation of ->nr_cpus_allowed if required.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1462969411-17735-2-git-send-email-bigeasy@linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Use the future-safe accessor for struct task_struct's.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1462969411-17735-1-git-send-email-bigeasy@linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Systems show a minimal load average of 0.00, 0.01, 0.05 even when they
have no load at all.

Uptime and /proc/loadavg on all systems with kernels released during the
last five years up until kernel version 4.6-rc5, show a 5- and 15-minute
minimum loadavg of 0.01 and 0.05 respectively. This should be 0.00 on
idle systems, but the way the kernel calculates this value prevents it
from getting lower than the mentioned values.

Likewise but not as obviously noticeable, a fully loaded system with no
processes waiting, shows a maximum 1/5/15 loadavg of 1.00, 0.99, 0.95
(multiplied by number of cores).

Once the (old) load becomes 93 or higher, it mathematically can never
get lower than 93, even when the active (load) remains 0 forever.
This results in the strange 0.00, 0.01, 0.05 uptime values on idle
systems.  Note: 93/2048 = 0.0454..., which rounds up to 0.05.

It is not correct to add a 0.5 rounding (=1024/2048) here, since the
result from this function is fed back into the next iteration again,
so the result of that +0.5 rounding value then gets multiplied by
(2048-2037), and then rounded again, so there is a virtual "ghost"
load created, next to the old and active load terms.

By changing the way the internally kept value is rounded, that internal
value equivalent now can reach 0.00 on idle, and 1.00 on full load. Upon
increasing load, the internally kept load value is rounded up, when the
load is decreasing, the load value is rounded down.

The modified code was tested on nohz=off and nohz kernels. It was tested
on vanilla kernel 4.6-rc5 and on centos 7.1 kernel 3.10.0-327. It was
tested on single, dual, and octal cores system. It was tested on virtual
hosts and bare hardware. No unwanted effects have been observed, and the
problems that the patch intended to fix were indeed gone.
Tested-by: NDamien Wyart <damien.wyart@free.fr>
Signed-off-by: NVik Heyndrickx <vik.heyndrickx@veribox.net>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Doug Smythies <dsmythies@telus.net>
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>
Fixes: 0f004f5a ("sched: Cure more NO_HZ load average woes")
Link: http://lkml.kernel.org/r/e8d32bff-d544-7748-72b5-3c86cc71f09f@veribox.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

In calculate_imbalance() load_above_capacity currently has the unit
[capacity] while it is used as being [load/capacity]. Not only is it
wrong it also makes it unlikely that load_above_capacity is ever used
as the subsequent code picks the smaller of load_above_capacity and
the avg_load

This patch ensures that load_above_capacity has the right unit
[load/capacity].
Signed-off-by: NMorten Rasmussen <morten.rasmussen@arm.com>
[ Changed changelog to note it was in capacity unit; +rebase. ]
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
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: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1461958364-675-4-git-send-email-dietmar.eggemann@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Wanpeng noted that the scale_load_down() in calculate_imbalance() was
weird. I agree, it should be SCHED_CAPACITY_SCALE, since we're going
to compare against busiest->group_capacity, which is in [capacity]
units.
Reported-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yuyang Du <yuyang.du@intel.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The following commit:

  9642d18e ("nohz: Affine unpinned timers to housekeepers")'

intended to affine unpinned timers to housekeepers:

  unpinned timers(full dynaticks, idle)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(full dynaticks, busy)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(houserkeepers, idle)    =>   nearest busy housekeepers(otherwise, fallback to itself)

However, the !idle_cpu(i) && is_housekeeping_cpu(cpu) check modified the
intention to:

  unpinned timers(full dynaticks, idle)   =>   any housekeepers(no mattter cpu topology)
  unpinned timers(full dynaticks, busy)   =>   any housekeepers(no mattter cpu topology)
  unpinned timers(housekeepers, idle)     =>   any busy cpus(otherwise, fallback to any housekeepers)

This patch fixes it by checking if there are busy housekeepers nearby,
otherwise falls to any housekeepers/itself. After the patch:

  unpinned timers(full dynaticks, idle)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(full dynaticks, busy)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(housekeepers, idle)     =>   nearest busy housekeepers(otherwise, fallback to itself)
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
[ Fixed the changelog. ]
Cc: Frederic Weisbecker <fweisbec@gmail.com>
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: linux-kernel@vger.kernel.org
Fixes: 'commit 9642d18e ("nohz: Affine unpinned timers to housekeepers")'
Link: http://lkml.kernel.org/r/1462344334-8303-1-git-send-email-wanpeng.li@hotmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Pavan reported that in the presence of very light tasks (or cgroups)
the placement of migrated tasks can cause severe fairness issues.

The problem is that enqueue_entity() places the task before it updates
time, thereby it can place the task far in the past (remember that
light tasks will shoot virtual time forward at a high speed, so in
relation to the pre-existing light task, we can land far in the past).

This is done because update_curr() needs the current task, and we
might be placing the current task.

The obvious solution is to differentiate between the current and any
other task; placing the current before we update time, and placing any
other task after, such that !curr tasks end up at the current moment
in time, and not in the past.

This commit re-introduces the previously reverted commit:

  3a47d512 ("sched/fair: Fix fairness issue on migration")

... which is now safe to do, after we've also fixed another
underlying bug first, in:

  sched/fair: Prepare to fix fairness problems on migration

and cleaned up other details in the migration code:

  sched/core: Kill sched_class::task_waking
Reported-by: NPavan Kondeti <pkondeti@codeaurora.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
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: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

With sched_class::task_waking being called only when we do
set_task_cpu(), we can make sched_class::migrate_task_rq() do the work
and eliminate sched_class::task_waking entirely.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Hunter <ahh@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: byungchul.park@lge.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Mike reported that our recent attempt to fix migration problems:

  3a47d512 ("sched/fair: Fix fairness issue on migration")

broke interactivity and the signal starve test. We reverted that
commit and now let's try it again more carefully, with some other
underlying problems fixed first.

One problem is that I assumed ENQUEUE_WAKING was only set when we do a
cross-cpu wakeup (migration), which isn't true. This means we now
destroy the vruntime history of tasks and wakeup-preemption suffers.

Cure this by making my assumption true, only call
sched_class::task_waking() when we do a cross-cpu wakeup. This avoids
the indirect call in the case we do a local wakeup.
Reported-by: NMike Galbraith <mgalbraith@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Hunter <ahh@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: byungchul.park@lge.com
Cc: linux-kernel@vger.kernel.org
Fixes: 3a47d512 ("sched/fair: Fix fairness issue on migration")
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Since I want to make ->task_woken() conditional on the task getting
migrated, we cannot use it to call record_wakee().

Move it to select_task_rq_fair(), which gets called in almost all the
same conditions. The only exception is if the woken task (@p) is
CPU-bound (as per the nr_cpus_allowed test in select_task_rq()).
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Hunter <ahh@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: byungchul.park@lge.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Conflicts:
	kernel/sched/core.c
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

Mike reported that this recent commit:

  3a47d512 ("sched/fair: Fix fairness issue on migration")

... broke interactivity and the signal starvation test.

We have a proper fix series in the works but ran out of time for
v4.6, so revert the commit.
Reported-by: NMike Galbraith <efault@gmx.de>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Pull PCI fixes from Bjorn Helgaas:
 "Since v4.5, we've WARNed during resume if a PCI device, including a
  Thunderbolt device, was added while we were suspended.  A change we
  merged for v4.6-rc1 turned that warning into a system hang.  These
  enumeration patches from Lukas Wunner fix this issue:

   - Fix BUG on device attach failure
   - Do not treat EPROBE_DEFER as device attach failure"

* tag 'pci-v4.6-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: Do not treat EPROBE_DEFER as device attach failure
  PCI: Fix BUG on device attach failure

Pull x86 fixes from Ingo Molnar:
 "Two topology corner case fixes, and a MAINTAINERS file update for
  mmiotrace maintenance"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/topology: Set x86_max_cores to 1 for CONFIG_SMP=n
  MAINTAINERS: Add mmiotrace entry
  x86/topology: Handle CPUID bogosity gracefully

Pull scheduler fixes from Ingo Molnar:
 "A UP kernel cpufreq fix and a rt/dl scheduler corner case fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/rt, sched/dl: Don't push if task's scheduling class was changed
  sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakage

We got this warning:

    WARNING: CPU: 1 PID: 2468 at kernel/sched/core.c:1161 set_task_cpu+0x1af/0x1c0
    [...]
    Call Trace:

    dump_stack+0x63/0x87
    __warn+0xd1/0xf0
    warn_slowpath_null+0x1d/0x20
    set_task_cpu+0x1af/0x1c0
    push_dl_task.part.34+0xea/0x180
    push_dl_tasks+0x17/0x30
    __balance_callback+0x45/0x5c
    __sched_setscheduler+0x906/0xb90
    SyS_sched_setattr+0x150/0x190
    do_syscall_64+0x62/0x110
    entry_SYSCALL64_slow_path+0x25/0x25

This corresponds to:

    WARN_ON_ONCE(p->state == TASK_RUNNING &&
             p->sched_class == &fair_sched_class &&
             (p->on_rq && !task_on_rq_migrating(p)))

It happens because in find_lock_later_rq(), the task whose scheduling
class was changed to fair class is still pushed away as if it were
a deadline task ...

So, check in find_lock_later_rq() after double_lock_balance(), if the
scheduling class of the deadline task was changed, break and retry.

Apply the same logic to RT tasks.
Signed-off-by: NXunlei Pang <xlpang@redhat.com>
Reviewed-by: NSteven Rostedt <rostedt@goodmis.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Link: http://lkml.kernel.org/r/1462767091-1215-1-git-send-email-xlpang@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Josef reported that the uncore driver trips over with CONFIG_SMP=n because
x86_max_cores is 16 instead of 12.

The reason is, that for SMP=n the extended topology detection is a NOOP and
the cache leaf is used to determine the number of cores. That's wrong in two
aspects:

1) The cache leaf enumerates the maximum addressable number of cores in the
   package, which is obviously not correct

2) UP has no business with topology bits at all.

Make intel_num_cpu_cores() return 1 for CONFIG_SMP=n
Reported-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team <Kernel-team@fb.com>
Cc: Kan Liang <kan.liang@intel.com>
Link: http://lkml.kernel.org/r/761b4a2a-0332-7954-f030-c6639f949612@fb.com

Pull libnvdimm build fix from Dan Williams:
 "A build fix for the usage of HPAGE_SIZE in the last libnvdimm pull
  request.

  I have taken note that the kbuild robot build success test does not
  include results for alpha_allmodconfig.  Thanks to Guenter for the
  report.  It's tagged for -stable since the original fix will land
  there and cause build problems"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm, pfn: fix ARCH=alpha allmodconfig build failure

Allowing unprivileged kernel profiling lets any user dump follow kernel
control flow and dump kernel registers.  This most likely allows trivial
kASLR bypassing, and it may allow other mischief as well.  (Off the top
of my head, the PERF_SAMPLE_REGS_INTR output during /dev/urandom reads
could be quite interesting.)
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Acked-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Merge fixes from Andrew Morton:
 "2 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  zsmalloc: fix zs_can_compact() integer overflow
  Revert "proc/base: make prompt shell start from new line after executing "cat /proc/$pid/wchan""

zs_can_compact() has two race conditions in its core calculation:

unsigned long obj_wasted = zs_stat_get(class, OBJ_ALLOCATED) -
				zs_stat_get(class, OBJ_USED);

1) classes are not locked, so the numbers of allocated and used
   objects can change by the concurrent ops happening on other CPUs
2) shrinker invokes it from preemptible context

Depending on the circumstances, thus, OBJ_ALLOCATED can become
less than OBJ_USED, which can result in either very high or
negative `total_scan' value calculated later in do_shrink_slab().

do_shrink_slab() has some logic to prevent those cases:

 vmscan: shrink_slab: zs_shrinker_scan+0x0/0x28 [zsmalloc] negative objects to delete nr=-62
 vmscan: shrink_slab: zs_shrinker_scan+0x0/0x28 [zsmalloc] negative objects to delete nr=-62
 vmscan: shrink_slab: zs_shrinker_scan+0x0/0x28 [zsmalloc] negative objects to delete nr=-64
 vmscan: shrink_slab: zs_shrinker_scan+0x0/0x28 [zsmalloc] negative objects to delete nr=-62
 vmscan: shrink_slab: zs_shrinker_scan+0x0/0x28 [zsmalloc] negative objects to delete nr=-62
 vmscan: shrink_slab: zs_shrinker_scan+0x0/0x28 [zsmalloc] negative objects to delete nr=-62

However, due to the way `total_scan' is calculated, not every
shrinker->count_objects() overflow can be spotted and handled.
To demonstrate the latter, I added some debugging code to do_shrink_slab()
(x86_64) and the results were:

 vmscan: OVERFLOW: shrinker->count_objects() == -1 [18446744073709551615]
 vmscan: but total_scan > 0: 92679974445502
 vmscan: resulting total_scan: 92679974445502
[..]
 vmscan: OVERFLOW: shrinker->count_objects() == -1 [18446744073709551615]
 vmscan: but total_scan > 0: 22634041808232578
 vmscan: resulting total_scan: 22634041808232578

Even though shrinker->count_objects() has returned an overflowed value,
the resulting `total_scan' is positive, and, what is more worrisome, it
is insanely huge. This value is getting used later on in
shrinker->scan_objects() loop:

        while (total_scan >= batch_size ||
               total_scan >= freeable) {
                unsigned long ret;
                unsigned long nr_to_scan = min(batch_size, total_scan);

                shrinkctl->nr_to_scan = nr_to_scan;
                ret = shrinker->scan_objects(shrinker, shrinkctl);
                if (ret == SHRINK_STOP)
                        break;
                freed += ret;

                count_vm_events(SLABS_SCANNED, nr_to_scan);
                total_scan -= nr_to_scan;

                cond_resched();
        }

`total_scan >= batch_size' is true for a very-very long time and
'total_scan >= freeable' is also true for quite some time, because
`freeable < 0' and `total_scan' is large enough, for example,
22634041808232578. The only break condition, in the given scheme of
things, is shrinker->scan_objects() == SHRINK_STOP test, which is a
bit too weak to rely on, especially in heavy zsmalloc-usage scenarios.

To fix the issue, take a pool stat snapshot and use it instead of
racy zs_stat_get() calls.

Link: http://lkml.kernel.org/r/20160509140052.3389-1-sergey.senozhatsky@gmail.comSigned-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>        [4.3+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts the 4.6-rc1 commit 7e2bc81d ("proc/base: make prompt
shell start from new line after executing "cat /proc/$pid/wchan")
because it breaks /proc/$PID/whcan formatting in ps and top.

Revert also because the patch is inconsistent - it adds a newline at the
end of only the '0' wchan, and does not add a newline when
/proc/$PID/wchan contains a symbol name.

eg.
$ ps -eo pid,stat,wchan,comm
PID STAT WCHAN  COMMAND
...
1189 S    -      dbus-launch
1190 Ssl  0
dbus-daemon
1198 Sl   0
lightdm
1299 Ss   ep_pol systemd
1301 S    -      (sd-pam)
1304 Ss   wait   sh
Signed-off-by: NRobin Humble <plaguedbypenguins@gmail.com>
Cc: Minfei Huang <mnfhuang@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull crypto fixes from Herbert Xu:
 "This fixes the following issues:

   - bug in ahash SG list walking that may lead to crashes

   - resource leak in qat

   - missing RSA dependency that causes it to fail"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: rsa - select crypto mgr dependency
  crypto: hash - Fix page length clamping in hash walk
  crypto: qat - fix adf_ctl_drv.c:undefined reference to adf_init_pf_wq
  crypto: qat - fix invalid pf2vf_resp_wq logic

Pull networking fixes from David Miller:

 1) Check klogctl failure correctly, from Colin Ian King.

 2) Prevent OOM when under memory pressure in flowcache, from Steffen
    Klassert.

 3) Fix info leak in llc and rtnetlink ifmap code, from Kangjie Lu.

 4) Memory barrier and multicast handling fixes in bnxt_en, from Michael
    Chan.

 5) Endianness bug in mlx5, from Daniel Jurgens.

 6) Fix disconnect handling in VSOCK, from Ian Campbell.

 7) Fix locking of netdev list walking in get_bridge_ifindices(), from
    Nikolay Aleksandrov.

 8) Bridge multicast MLD parser can look at wrong packet offsets, fix
    from Linus Lüssing.

 9) Fix chip hang in qede driver, from Sudarsana Reddy Kalluru.

10) Fix missing setting of encapsulation before inner handling completes
    in udp_offload code, from Jarno Rajahalme.

11) Missing rollbacks during LAG join and flood configuration failures
    in mlxsw driver, from Ido Schimmel.

12) Fix error code checks in netxen driver, from Dan Carpenter.

13) Fix key size in new macsec driver, from Sabrina Dubroca.

14) Fix mlx5/VXLAN dependencies, from Arnd Bergmann.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (29 commits)
  net/mlx5e: make VXLAN support conditional
  Revert "net/mlx5: Kconfig: Fix MLX5_EN/VXLAN build issue"
  macsec: key identifier is 128 bits, not 64
  Documentation/networking: more accurate LCO explanation
  macvtap: segmented packet is consumed
  tools: bpf_jit_disasm: check for klogctl failure
  qede: uninitialized variable in qede_start_xmit()
  netxen: netxen_rom_fast_read() doesn't return -1
  netxen: reversed condition in netxen_nic_set_link_parameters()
  netxen: fix error handling in netxen_get_flash_block()
  mlxsw: spectrum: Add missing rollback in flood configuration
  mlxsw: spectrum: Fix rollback order in LAG join failure
  udp_offload: Set encapsulation before inner completes.
  udp_tunnel: Remove redundant udp_tunnel_gro_complete().
  qede: prevent chip hang when increasing channels
  net: ipv6: tcp reset, icmp need to consider L3 domain
  bridge: fix igmp / mld query parsing
  net: bridge: fix old ioctl unlocked net device walk
  VSOCK: do not disconnect socket when peer has shutdown SEND only
  net/mlx4_en: Fix endianness bug in IPV6 csum calculation
  ...

gcc support for __builtin_bswap16() was supposedly added for powerpc in
gcc 4.6, and was then later added for other architectures in gcc 4.8.

However, Stephen Rothwell reported that attempting to use it on powerpc
in gcc 4.6 fails with:

  lib/vsprintf.c:160:2: error: initializer element is not constant
  lib/vsprintf.c:160:2: error: (near initialization for 'decpair[0]')
  lib/vsprintf.c:160:2: error: initializer element is not constant
  lib/vsprintf.c:160:2: error: (near initialization for 'decpair[1]')
  ...

I'm not entirely sure what those errors mean, but I don't see them on
gcc 4.8.  So let's consider gcc 4.8 to be the official starting point
for __builtin_bswap16().

Arnd Bergmann adds:
 "I found the commit in gcc-4.8 that replaced the powerpc-specific
  implementation of __builtin_bswap16 with an architecture-independent
  one.  Apparently the powerpc version (gcc-4.6 and 4.7) just mapped to
  the lhbrx/sthbrx instructions, so it ended up not being a constant,
  though the intent of the patch was mainly to add support for the
  builtin to x86:

    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52624

  has the patch that went into gcc-4.8 and more information."

Fixes: 7322dd75 ("byteswap: try to avoid __builtin_constant_p gcc bug")
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Tested-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

... the comment clearly refers to wake_up_q(), and not
wake_up_list().
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1462766290-28664-1-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

Remove unused variable 'ret', and directly return 0.
Signed-off-by: NMuhammad Falak R Wani <falakreyaz@gmail.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/1462441879-10092-1-git-send-email-falakreyaz@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Saeed Mahameed says:

====================
net/mlx5e: Kconfig fixes for VxLAN

Reposting to net the build errors fixes posted by Arnd last week.

Originally Arnd posted those fixes to net-next, while the issue
is also seen in net.  For net-next a different approach is required
for fixing the issue as VXLAN and Device Drivers are no longer
dependent, but there is no harm for those fixes to get into net-next.

Optionally, once net is merged into net-next we can
Revert "net/mlx5e: make VXLAN support conditional" as the
CONFIG_MLX5_CORE_EN_VXLAN will no longer be required.

Applied on top: 28892865 ('mlxsw: spectrum: Add missing rollback in flood configuration')
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

VXLAN can be disabled at compile-time or it can be a loadable
module while mlx5 is built-in, which leads to a link error:

drivers/net/built-in.o: In function `mlx5e_create_netdev':
ntb_netdev.c:(.text+0x106de4): undefined reference to `vxlan_get_rx_port'

This avoids the link error and makes the vxlan code optional,
like the other ethernet drivers do as well.

Link: https://patchwork.ozlabs.org/patch/589296/
Fixes: b3f63c3d ("net/mlx5e: Add netdev support for VXLAN tunneling")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 69976fb1.

We cannot select VXLAN when IPv4 support is disabled, that just gives
us additional build errors, including:

warning: (MLX5_CORE_EN) selects VXLAN which has unmet direct dependencies (NETDEVICES && NET_CORE && INET)
In file included from ../drivers/net/vxlan.c:36:0:
include/net/udp_tunnel.h: In function 'udp_tunnel_handle_offloads':
include/net/udp_tunnel.h:112:9: error: implicit declaration of function 'iptunnel_handle_offloads' [-Werror=implicit-function-declaration]
  return iptunnel_handle_offloads(skb, type);
         ^~~~~~~~~~~~~~~~~~~~~~~~

I'm sending a proper fix for the original bug in a separate patch.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The MACsec standard mentions a key identifier for each key, but
doesn't specify anything about it, so I arbitrarily chose 64 bits.

IEEE 802.1X-2010 specifies MKA (MACsec Key Agreement), and defines the
key identifier to be 128 bits (96 bits "member identifier" + 32 bits
"key number").
Signed-off-by: NSabrina Dubroca <sd@queasysnail.net>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In few places the term "ones-complement sum" was used but the actual
meaning is "the complement of the ones-complement sum".

Also, avoid enclosing long statements with underscore, to ease
readability.
Signed-off-by: NShmulik Ladkani <shmulik.ladkani@gmail.com>
Acked-by: NEdward Cree <ecree@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If GSO packet is segmented and its segments are properly queued,
we call consume_skb() instead of kfree_skb() to be drop monitor
friendly.

Fixes: 3e4f8b78 ("macvtap: Perform GSO on forwarding path.")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Vlad Yasevich <vyasevic@redhat.com>
Reviewed-by: NShmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

klogctl can fail and return -ve len, so check for this and
return NULL to avoid passing a (size_t)-1 to malloc.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

"data_split" was never set to false.  It's just uninitialized.

Fixes: 2950219d ('qede: Add basic network device support')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The Nouveau maintainers would like to follow and review mmiotrace
changes as well, so create a separate entry for that code. The high
level bits are living in the tracing code, the low level bits in the
x86 code.
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Acked-by: NPekka Paalanen <ppaalanen@gmail.com>
Acked-by: Nkarol herbst <karolherbst@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The error handling is broken here.  netxen_rom_fast_read() returns zero
on success and -EIO on error.  It never returns -1.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>