linux.git/kernel, branch v3.14.31

mm: page_alloc: use jump labels to avoid checking number_of_cpusets

2015-01-30T01:40:51+00:00

commit 664eeddeef6539247691197c1ac124d4aa872ab6 upstream.

If cpusets are not in use then we still check a global variable on every
page allocation.  Use jump labels to avoid the overhead.

Signed-off-by: Mel Gorman 
Reviewed-by: Rik van Riel 
Cc: Johannes Weiner 
Cc: Vlastimil Babka 
Cc: Jan Kara 
Cc: Michal Hocko 
Cc: Hugh Dickins 
Cc: Dave Hansen 
Cc: Theodore Ts'o 
Cc: "Paul E. McKenney" 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Mel Gorman 
Signed-off-by: Greg Kroah-Hartman

time: adjtimex: Validate the ADJ_FREQUENCY values

2015-01-30T01:40:49+00:00

commit 5e5aeb4367b450a28f447f6d5ab57d8f2ab16a5f upstream.

Verify that the frequency value from userspace is valid and makes sense.

Unverified values can cause overflows later on.

Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Signed-off-by: Sasha Levin 
[jstultz: Fix up bug for negative values and drop redunent cap check]
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

time: settimeofday: Validate the values of tv from user

2015-01-30T01:40:49+00:00

commit 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 upstream.

An unvalidated user input is multiplied by a constant, which can result in
an undefined behaviour for large values. While this is validated later,
we should avoid triggering undefined behaviour.

Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Signed-off-by: Sasha Levin 
[jstultz: include trivial milisecond->microsecond correction noticed
by Andy]
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

genirq: Prevent proc race against freeing of irq descriptors

2015-01-27T16:18:55+00:00

commit c291ee622165cb2c8d4e7af63fffd499354a23be upstream.

Since the rework of the sparse interrupt code to actually free the
unused interrupt descriptors there exists a race between the /proc
interfaces to the irq subsystem and the code which frees the interrupt
descriptor.

CPU0				CPU1
				show_interrupts()
				  desc = irq_to_desc(X);
free_desc(desc)
  remove_from_radix_tree();
  kfree(desc);
				  raw_spinlock_irq(&desc->lock);

/proc/interrupts is the only interface which can actively corrupt
kernel memory via the lock access. /proc/stat can only read from freed
memory. Extremly hard to trigger, but possible.

The interfaces in /proc/irq/N/ are not affected by this because the
removal of the proc file is serialized in procfs against concurrent
readers/writers. The removal happens before the descriptor is freed.

For architectures which have CONFIG_SPARSE_IRQ=n this is a non issue
as the descriptor is never freed. It's merely cleared out with the irq
descriptor lock held. So any concurrent proc access will either see
the old correct value or the cleared out ones.

Protect the lookup and access to the irq descriptor in
show_interrupts() with the sparse_irq_lock.

Provide kstat_irqs_usr() which is protecting the lookup and access
with sparse_irq_lock and switch /proc/stat to use it.

Document the existing kstat_irqs interfaces so it's clear that the
caller needs to take care about protection. The users of these
interfaces are either not affected due to SPARSE_IRQ=n or already
protected against removal.

Fixes: 1f5a5b87f78f "genirq: Implement a sane sparse_irq allocator"
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

tick/powerclamp: Remove tick_nohz_idle abuse

2015-01-27T16:18:55+00:00

commit a5fd9733a30d18d7ac23f17080e7e07bb3205b69 upstream.

commit 4dbd27711cd9 "tick: export nohz tick idle symbols for module
use" was merged via the thermal tree without an explicit ack from the
relevant maintainers.

The exports are abused by the intel powerclamp driver which implements
a fake idle state from a sched FIFO task. This causes all kinds of
wreckage in the NOHZ core code which rightfully assumes that
tick_nohz_idle_enter/exit() are only called from the idle task itself.

Recent changes in the NOHZ core lead to a failure of the powerclamp
driver and now people try to hack completely broken and backwards
workarounds into the NOHZ core code. This is completely unacceptable
and just papers over the real problem. There are way more subtle
issues lurking around the corner.

The real solution is to fix the powerclamp driver by rewriting it with
a sane concept, but that's beyond the scope of this.

So the only solution for now is to remove the calls into the core NOHZ
code from the powerclamp trainwreck along with the exports.

Fixes: d6d71ee4a14a "PM: Introduce Intel PowerClamp Driver"
Signed-off-by: Thomas Gleixner 
Cc: Preeti U Murthy 
Cc: Viresh Kumar 
Cc: Frederic Weisbecker 
Cc: Fengguang Wu 
Cc: Frederic Weisbecker 
Cc: Pan Jacob jun 
Cc: LKP 
Cc: Peter Zijlstra 
Cc: Zhang Rui 
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1412181110110.17382@nanos
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

perf: Fix events installation during moving group

2015-01-16T14:59:34+00:00

commit 9fc81d87420d0d3fd62d5e5529972c0ad9eab9cc upstream.

We allow PMU driver to change the cpu on which the event
should be installed to. This happened in patch:

  e2d37cd213dc ("perf: Allow the PMU driver to choose the CPU on which to install events")

This patch also forces all the group members to follow
the currently opened events cpu if the group happened
to be moved.

This and the change of event->cpu in perf_install_in_context()
function introduced in:

  0cda4c023132 ("perf: Introduce perf_pmu_migrate_context()")

forces group members to change their event->cpu,
if the currently-opened-event's PMU changed the cpu
and there is a group move.

Above behaviour causes problem for breakpoint events,
which uses event->cpu to touch cpu specific data for
breakpoints accounting. By changing event->cpu, some
breakpoints slots were wrongly accounted for given
cpu.

Vinces's perf fuzzer hit this issue and caused following
WARN on my setup:

   WARNING: CPU: 0 PID: 20214 at arch/x86/kernel/hw_breakpoint.c:119 arch_install_hw_breakpoint+0x142/0x150()
   Can't find any breakpoint slot
   [...]

This patch changes the group moving code to keep the event's
original cpu.

Reported-by: Vince Weaver 
Signed-off-by: Jiri Olsa 
Cc: Arnaldo Carvalho de Melo 
Cc: Frederic Weisbecker 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Vince Weaver 
Cc: Yan, Zheng 
Link: http://lkml.kernel.org/r/1418243031-20367-3-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

sched/deadline: Avoid double-accounting in case of missed deadlines

2015-01-16T14:59:33+00:00

commit 269ad8015a6b2bb1cf9e684da4921eb6fa0a0c88 upstream.

The dl_runtime_exceeded() function is supposed to ckeck if
a SCHED_DEADLINE task must be throttled, by checking if its
current runtime is <= 0. However, it also checks if the
scheduling deadline has been missed (the current time is
larger than the current scheduling deadline), further
decreasing the runtime if this happens.
This "double accounting" is wrong:

- In case of partitioned scheduling (or single CPU), this
  happens if task_tick_dl() has been called later than expected
  (due to small HZ values). In this case, the current runtime is
  also negative, and replenish_dl_entity() can take care of the
  deadline miss by recharging the current runtime to a value smaller
  than dl_runtime

- In case of global scheduling on multiple CPUs, scheduling
  deadlines can be missed even if the task did not consume more
  runtime than expected, hence penalizing the task is wrong

This patch fix this problem by throttling a SCHED_DEADLINE task
only when its runtime becomes negative, and not modifying the runtime

Signed-off-by: Luca Abeni 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Juri Lelli 
Cc: Dario Faggioli 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/1418813432-20797-3-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

sched/deadline: Fix migration of SCHED_DEADLINE tasks

2015-01-16T14:59:33+00:00

commit 6a503c3be937d275113b702e0421e5b0720abe8a upstream.

According to global EDF, tasks should be migrated between runqueues
without checking if their scheduling deadlines and runtimes are valid.
However, SCHED_DEADLINE currently performs such a check:
a migration happens doing:

	deactivate_task(rq, next_task, 0);
	set_task_cpu(next_task, later_rq->cpu);
	activate_task(later_rq, next_task, 0);

which ends up calling dequeue_task_dl(), setting the new CPU, and then
calling enqueue_task_dl().

enqueue_task_dl() then calls enqueue_dl_entity(), which calls
update_dl_entity(), which can modify scheduling deadline and runtime,
breaking global EDF scheduling.

As a result, some of the properties of global EDF are not respected:
for example, a taskset {(30, 80), (40, 80), (120, 170)} scheduled on
two cores can have unbounded response times for the third task even
if 30/80+40/80+120/170 = 1.5809 < 2

This can be fixed by invoking update_dl_entity() only in case of
wakeup, or if this is a new SCHED_DEADLINE task.

Signed-off-by: Luca Abeni 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Juri Lelli 
Cc: Dario Faggioli 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/1418813432-20797-2-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting

2015-01-08T18:00:50+00:00

commit 24c037ebf5723d4d9ab0996433cee4f96c292a4d upstream.

alloc_pid() does get_pid_ns() beforehand but forgets to put_pid_ns() if it
fails because disable_pid_allocation() was called by the exiting
child_reaper.

We could simply move get_pid_ns() down to successful return, but this fix
tries to be as trivial as possible.

Signed-off-by: Oleg Nesterov 
Reviewed-by: "Eric W. Biederman" 
Cc: Aaron Tomlin 
Cc: Pavel Emelyanov 
Cc: Serge Hallyn 
Cc: Sterling Alexander 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

audit: restore AUDIT_LOGINUID unset ABI

2015-01-08T18:00:50+00:00

commit 041d7b98ffe59c59fdd639931dea7d74f9aa9a59 upstream.

A regression was caused by commit 780a7654cee8:
	 audit: Make testing for a valid loginuid explicit.
(which in turn attempted to fix a regression caused by e1760bd)

When audit_krule_to_data() fills in the rules to get a listing, there was a
missing clause to convert back from AUDIT_LOGINUID_SET to AUDIT_LOGINUID.

This broke userspace by not returning the same information that was sent and
expected.

The rule:
	auditctl -a exit,never -F auid=-1
gives:
	auditctl -l
		LIST_RULES: exit,never f24=0 syscall=all
when it should give:
		LIST_RULES: exit,never auid=-1 (0xffffffff) syscall=all

Tag it so that it is reported the same way it was set.  Create a new
private flags audit_krule field (pflags) to store it that won't interact with
the public one from the API.

Signed-off-by: Richard Guy Briggs 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman