linux-stable.git/kernel, branch v3.0.13

clockevents: Set noop handler in clockevents_exchange_device()

2011-12-09T16:52:53+00:00

commit de28f25e8244c7353abed8de0c7792f5f883588c upstream.

If a device is shutdown, then there might be a pending interrupt,
which will be processed after we reenable interrupts, which causes the
original handler to be run. If the old handler is the (broadcast)
periodic handler the shutdown state might hang the kernel completely.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

clocksource: Fix bug with max_deferment margin calculation

2011-12-09T16:52:52+00:00

commit b1f919664d04a8d0ba29cb76673c7ca3325a2006 upstream.

In order to leave a margin of 12.5% we should >> 3 not >> 5.

Signed-off-by: Yang Honggang (Joseph) 
[jstultz: Modified commit subject]
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

jump_label: jump_label_inc may return before the code is patched

2011-12-09T16:52:50+00:00

commit bbbf7af4bf8fc69bc751818cf30521080fa47dcb upstream.

If cpu A calls jump_label_inc() just after atomic_add_return() is
called by cpu B, atomic_inc_not_zero() will return value greater then
zero and jump_label_inc() will return to a caller before jump_label_update()
finishes its job on cpu B.

Link: http://lkml.kernel.org/r/20111018175551.GH17571@redhat.com

Cc: Peter Zijlstra 
Acked-by: Jason Baron 
Signed-off-by: Gleb Natapov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tick-broadcast: Stop active broadcast device when replacing it

2011-12-09T16:52:48+00:00

commit c1be84309c58b1e7c6d626e28fba41a22b364c3d upstream.

When a better rated broadcast device is installed, then the current
active device is not disabled, which results in two running broadcast
devices.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

tracing: fix event_subsystem ref counting

2011-12-09T16:52:48+00:00

commit cb59974742aea24adf6637eb0c4b8e7b48bca6fb upstream.

Fix a bug introduced by e9dbfae5, which prevents event_subsystem from
ever being released.

Ref_count was added to keep track of subsystem users, not for counting
events.  Subsystem is created with ref_count = 1, so there is no need to
increment it for every event, we have nr_events for that.  Fix this by
touching ref_count only when we actually have a new user -
subsystem_open().

Signed-off-by: Ilya Dryomov 
Link: http://lkml.kernel.org/r/1320052062-7846-1-git-send-email-idryomov@gmail.com
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

trace_events_filter: Use rcu_assign_pointer() when setting ftrace_event_call->filter

2011-12-09T16:52:47+00:00

commit d3d9acf646679c1981032b0985b386d12fccc60c upstream.

ftrace_event_call->filter is sched RCU protected but didn't use
rcu_assign_pointer().  Use it.

TODO: Add proper __rcu annotation to call->filter and all its users.

-v2: Use RCU_INIT_POINTER() for %NULL clearing as suggested by Eric.

Link: http://lkml.kernel.org/r/20111123164949.GA29639@google.com

Cc: Eric Dumazet 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Signed-off-by: Tejun Heo 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

genirq: Fix race condition when stopping the irq thread

2011-12-09T16:52:46+00:00

commit 550acb19269d65f32e9ac4ddb26c2b2070e37f1c upstream.

In irq_wait_for_interrupt(), the should_stop member is verified before
setting the task's state to TASK_INTERRUPTIBLE and calling schedule().
In case kthread_stop sets should_stop and wakes up the process after
should_stop is checked by the irq thread but before the task's state
is changed, the irq thread might never exit:

kthread_stop                    irq_wait_for_interrupt
------------                    ----------------------

                                 ...
...                              while (!kthread_should_stop()) {
kthread->should_stop = 1;
wake_up_process(k);
wait_for_completion(&kthread->exited);
...
                                     set_current_state(TASK_INTERRUPTIBLE);

                                     ...

                                     schedule();
                                 }

Fix this by checking if the thread should stop after modifying the
task's state.

[ tglx: Simplified it a bit ]

Signed-off-by: Ido Yariv 
Link: http://lkml.kernel.org/r/1322740508-22640-1-git-send-email-ido@wizery.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

hrtimer: Fix extra wakeups from __remove_hrtimer()

2011-12-09T16:52:28+00:00

commit 27c9cd7e601632b3794e1c3344d37b86917ffb43 upstream.

__remove_hrtimer() attempts to reprogram the clockevent device when
the timer being removed is the next to expire. However,
__remove_hrtimer() reprograms the clockevent *before* removing the
timer from the timerqueue and thus when hrtimer_force_reprogram()
finds the next timer to expire it finds the timer we're trying to
remove.

This is especially noticeable when the system switches to NOHz mode
and the system tick is removed. The timer tick is removed from the
system but the clockevent is programmed to wakeup in another HZ
anyway.

Silence the extra wakeup by removing the timer from the timerqueue
before calling hrtimer_force_reprogram() so that we actually program
the clockevent for the next timer to expire.

This was broken by 998adc3 "hrtimers: Convert hrtimers to use
timerlist infrastructure".

Signed-off-by: Jeff Ohlstein 
Link: http://lkml.kernel.org/r/1321660030-8520-1-git-send-email-johlstei@codeaurora.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

timekeeping: add arch_offset hook to ktime_get functions

2011-12-09T16:52:28+00:00

commit d004e024058a0eaca097513ce62cbcf978913e0a upstream.

ktime_get and ktime_get_ts were calling timekeeping_get_ns()
but later they were not calling arch_gettimeoffset() so architectures
using this mechanism returned 0 ns when calling these functions.

This happened for example when running Busybox's ping which calls
syscall(__NR_clock_gettime, CLOCK_MONOTONIC, ts) which eventually
calls ktime_get. As a result the returned ping travel time was zero.

Signed-off-by: Hector Palacios 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

cgroup_freezer: fix freezing groups with stopped tasks

2011-12-09T16:52:27+00:00

commit 884a45d964dd395eda945842afff5e16bcaedf56 upstream.

2d3cbf8b (cgroup_freezer: update_freezer_state() does incorrect state
transitions) removed is_task_frozen_enough and replaced it with a simple
frozen call. This, however, breaks freezing for a group with stopped tasks
because those cannot be frozen and so the group remains in CGROUP_FREEZING
state (update_if_frozen doesn't count stopped tasks) and never reaches
CGROUP_FROZEN.

Let's add is_task_frozen_enough back and use it at the original locations
(update_if_frozen and try_to_freeze_cgroup). Semantically we consider
stopped tasks as frozen enough so we should consider both cases when
testing frozen tasks.

Testcase:
mkdir /dev/freezer
mount -t cgroup -o freezer none /dev/freezer
mkdir /dev/freezer/foo
sleep 1h &
pid=$!
kill -STOP $pid
echo $pid > /dev/freezer/foo/tasks
echo FROZEN > /dev/freezer/foo/freezer.state
while true
do
	cat /dev/freezer/foo/freezer.state
	[ "`cat /dev/freezer/foo/freezer.state`" = "FROZEN" ] && break
	sleep 1
done
echo OK

Signed-off-by: Michal Hocko 
Acked-by: Li Zefan 
Cc: Tomasz Buchert 
Cc: Paul Menage 
Cc: Andrew Morton 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman