* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
lockdep: Fix lockdep_no_validate against IRQ states
mutex: Make mutex_destroy() an inline function
plist: Remove the need to supply locks to plist heads
lockup detector: Fix reference to the non-existent CONFIG_DETECT_SOFTLOCKUP option
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6: (51 commits)
PM: Improve error code of pm_notifier_call_chain()
PM: Add "RTC" to PM trace time stamps to avoid confusion
PM / Suspend: Export suspend_set_ops, suspend_valid_only_mem
PM / Suspend: Add .suspend_again() callback to suspend_ops
PM / OPP: Introduce function to free cpufreq table
ARM / shmobile: Return -EBUSY from A4LC power off if A3RV is active
PM / Domains: Take .power_off() error code into account
ARM / shmobile: Use genpd_queue_power_off_work()
ARM / shmobile: Use pm_genpd_poweroff_unused()
PM / Domains: Introduce function to power off all unused PM domains
OMAP: PM: disable idle on suspend for GPIO and UART
OMAP: PM: omap_device: add API to disable idle on suspend
OMAP: PM: omap_device: add system PM methods for PM domain handling
OMAP: PM: omap_device: conditionally use PM domain runtime helpers
PM / Runtime: Add new helper function: pm_runtime_status_suspended()
PM / Domains: Queue up power off work only if it is not pending
PM / Domains: Improve handling of wakeup devices during system suspend
PM / Domains: Do not restore all devices on power off error
PM / Domains: Allow callbacks to execute all runtime PM helpers
PM / Domains: Do not execute device callbacks under locks
...
* 'for-3.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: separate out drain_workqueue() from destroy_workqueue()
workqueue: remove cancel_rearming_delayed_work[queue]()
* 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc: (39 commits)
ptrace: do_wait(traced_leader_killed_by_mt_exec) can block forever
ptrace: fix ptrace_signal() && STOP_DEQUEUED interaction
connector: add an event for monitoring process tracers
ptrace: dont send SIGSTOP on auto-attach if PT_SEIZED
ptrace: mv send-SIGSTOP from do_fork() to ptrace_init_task()
ptrace_init_task: initialize child->jobctl explicitly
has_stopped_jobs: s/task_is_stopped/SIGNAL_STOP_STOPPED/
ptrace: make former thread ID available via PTRACE_GETEVENTMSG after PTRACE_EVENT_EXEC stop
ptrace: wait_consider_task: s/same_thread_group/ptrace_reparented/
ptrace: kill real_parent_is_ptracer() in in favor of ptrace_reparented()
ptrace: ptrace_reparented() should check same_thread_group()
redefine thread_group_leader() as exit_signal >= 0
do not change dead_task->exit_signal
kill task_detached()
reparent_leader: check EXIT_DEAD instead of task_detached()
make do_notify_parent() __must_check, update the callers
__ptrace_detach: avoid task_detached(), check do_notify_parent()
kill tracehook_notify_death()
make do_notify_parent() return bool
ptrace: s/tracehook_tracer_task()/ptrace_parent()/
...
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1287 commits)
icmp: Fix regression in nexthop resolution during replies.
net: Fix ppc64 BPF JIT dependencies.
acenic: include NET_SKB_PAD headroom to incoming skbs
ixgbe: convert to ndo_fix_features
ixgbe: only enable WoL for magic packet by default
ixgbe: remove ifdef check for non-existent define
ixgbe: Pass staterr instead of re-reading status and error bits from descriptor
ixgbe: Move interrupt related values out of ring and into q_vector
ixgbe: add structure for containing RX/TX rings to q_vector
ixgbe: inline the ixgbe_maybe_stop_tx function
ixgbe: Update ATR to use recorded TX queues instead of CPU for routing
igb: Fix for DH89xxCC near end loopback test
e1000: always call e1000_check_for_link() on e1000_ce4100 MACs.
netxen: add fw version compatibility check
be2net: request native mode each time the card is reset
ipv4: Constrain UFO fragment sizes to multiples of 8 bytes
virtio_net: Fix panic in virtnet_remove
ipv6: make fragment identifications less predictable
ipv6: unshare inetpeers
can: make function can_get_bittiming static
...
Thomas noticed that a lock marked with lockdep_set_novalidate_class()
will still trigger warnings for IRQ inversions. Cure this by skipping
those when marking irq state.
Reported-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-2dp5vmpsxeraqm42kgww6ge2@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Simple test-case,
int main(void)
{
int pid, status;
pid = fork();
if (!pid) {
pause();
assert(0);
return 0x23;
}
assert(ptrace(PTRACE_ATTACH, pid, 0,0) == 0);
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP);
kill(pid, SIGCONT); // <--- also clears STOP_DEQUEUD
assert(ptrace(PTRACE_CONT, pid, 0,0) == 0);
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGCONT);
assert(ptrace(PTRACE_CONT, pid, 0, SIGSTOP) == 0);
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP);
kill(pid, SIGKILL);
return 0;
}
Without the patch it hangs. After the patch SIGSTOP "injected" by the
tracer is not ignored and stops the tracee.
Note also that if this test-case uses, say, SIGWINCH instead of SIGCONT,
everything works without the patch. This can't be right, and this is
confusing.
The problem is that SIGSTOP (or any other sig_kernel_stop() signal) has
no effect without JOBCTL_STOP_DEQUEUED. This means it is simply ignored
after PTRACE_CONT unless JOBCTL_STOP_DEQUEUED was set "by accident", say
it wasn't cleared after initial SIGSTOP sent by PTRACE_ATTACH.
At first glance we could change ptrace_signal() to add STOP_DEQUEUED
after return from ptrace_stop(), but this is not right in case when the
tracer does not change the reported SIGSTOP and SIGCONT comes in between.
This is even more wrong with PT_SEIZED, SIGCONT adds JOBCTL_TRAP_NOTIFY
which will be "lost" during the TRAP_STOP | TRAP_NOTIFY report.
So lets add STOP_DEQUEUED _before_ we report the signal. It has no effect
unless sig_kernel_stop() == T after the tracer resumes us, and in the
latter case the pending STOP_DEQUEUED means no SIGCONT in between, we
should stop.
Note also that if SIGCONT was sent, PT_SEIZED tracee will correctly
report PTRACE_EVENT_STOP/SIGTRAP and thus the tracer can notice the fact
SIGSTOP was cancelled.
Also, move the current->ptrace check from ptrace_signal() to its caller,
get_signal_to_deliver(), this looks more natural.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
The __lock_task_sighand() function calls rcu_read_lock() with interrupts
and preemption enabled, but later calls rcu_read_unlock() with interrupts
disabled. It is therefore possible that this RCU read-side critical
section will be preempted and later RCU priority boosted, which means that
rcu_read_unlock() will call rt_mutex_unlock() in order to deboost itself, but
with interrupts disabled. This results in lockdep splats, so this commit
nests the RCU read-side critical section within the interrupt-disabled
region of code. This prevents the RCU read-side critical section from
being preempted, and thus prevents the attempt to deboost with interrupts
disabled.
It is quite possible that a better long-term fix is to make rt_mutex_unlock()
disable irqs when acquiring the rt_mutex structure's ->wait_lock.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_read_unlock_special() function relies on in_irq() to exclude
scheduler activity from interrupt level. This fails because exit_irq()
can invoke the scheduler after clearing the preempt_count() bits that
in_irq() uses to determine that it is at interrupt level. This situation
can result in failures as follows:
$task IRQ SoftIRQ
rcu_read_lock()
/* do stuff */
<preempt> |= UNLOCK_BLOCKED
rcu_read_unlock()
--t->rcu_read_lock_nesting
irq_enter();
/* do stuff, don't use RCU */
irq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
invoke_softirq()
ttwu();
spin_lock_irq(&pi->lock)
rcu_read_lock();
/* do stuff */
rcu_read_unlock();
rcu_read_unlock_special()
rcu_report_exp_rnp()
ttwu()
spin_lock_irq(&pi->lock) /* deadlock */
rcu_read_unlock_special(t);
Ed can simply trigger this 'easy' because invoke_softirq() immediately
does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff
first, but even without that the above happens.
Cure this by also excluding softirqs from the
rcu_read_unlock_special() handler and ensuring the force_irqthreads
ksoftirqd/# wakeup is done from full softirq context.
[ Alternatively, delaying the ->rcu_read_lock_nesting decrement
until after the special handling would make the thing more robust
in the face of interrupts as well. And there is a separate patch
for that. ]
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-and-tested-by: Ed Tomlinson <edt@aei.ca>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual
work. Traditionally we never did any actual work from the resched IPI
and all magic happened in the return from interrupt path.
Now that we do do some work, we need to ensure irq_{enter,exit} are
called so that we don't confuse things.
This affects things like timekeeping, NO_HZ and RCU, basically
everything with a hook in irq_enter/exit.
Explicit examples of things going wrong are:
sched_clock_cpu() -- has a callback when leaving NO_HZ state to take
a new reading from GTOD and TSC. Without this
callback, time is stuck in the past.
RCU -- needs in_irq() to work in order to avoid some nasty deadlocks
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The addition of RCU read-side critical sections within runqueue and
priority-inheritance lock critical sections introduced some deadlock
cycles, for example, involving interrupts from __rcu_read_unlock()
where the interrupt handlers call wake_up(). This situation can cause
the instance of __rcu_read_unlock() invoked from interrupt to do some
of the processing that would otherwise have been carried out by the
task-level instance of __rcu_read_unlock(). When the interrupt-level
instance of __rcu_read_unlock() is called with a scheduler lock held
from interrupt-entry/exit situations where in_irq() returns false,
deadlock can result.
This commit resolves these deadlocks by using negative values of
the per-task ->rcu_read_lock_nesting counter to indicate that an
instance of __rcu_read_unlock() is in flight, which in turn prevents
instances from interrupt handlers from doing any special processing.
This patch is inspired by Steven Rostedt's earlier patch that similarly
made __rcu_read_unlock() guard against interrupt-mediated recursion
(see https://lkml.org/lkml/2011/7/15/326), but this commit refines
Steven's approach to avoid the need for preemption disabling on the
__rcu_read_unlock() fastpath and to also avoid the need for manipulating
a separate per-CPU variable.
This patch avoids need for preempt_disable() by instead using negative
values of the per-task ->rcu_read_lock_nesting counter. Note that nested
rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will
never see ->rcu_read_lock_nesting go to zero, and will therefore never
invoke rcu_read_unlock_special(), thus preventing them from seeing the
RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special.
This patch also adds a check for ->rcu_read_unlock_special being negative
in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS
bit from being set should a scheduling-clock interrupt occur while
__rcu_read_unlock() is exiting from an outermost RCU read-side critical
section.
Of course, __rcu_read_unlock() can be preempted during the time that
->rcu_read_lock_nesting is negative. This could result in the setting
of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it,
and would also result it this task being queued on the corresponding
rcu_node structure's blkd_tasks list. Therefore, some later RCU read-side
critical section would enter rcu_read_unlock_special() to clean up --
which could result in deadlock if that critical section happened to be in
the scheduler where the runqueue or priority-inheritance locks were held.
This situation is dealt with by making rcu_preempt_note_context_switch()
check for negative ->rcu_read_lock_nesting, thus refraining from
queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are
already exiting from the outermost RCU read-side critical section (in
other words, we really are no longer actually in that RCU read-side
critical section). In addition, rcu_preempt_note_context_switch()
invokes rcu_read_unlock_special() to carry out the cleanup in this case,
which clears out the ->rcu_read_unlock_special bits and dequeues the task
(if necessary), in turn avoiding needless delay of the current RCU grace
period and needless RCU priority boosting.
It is still illegal to call rcu_read_unlock() while holding a scheduler
lock if the prior RCU read-side critical section has ever had either
preemption or irqs enabled. However, the common use case is legal,
namely where then entire RCU read-side critical section executes with
irqs disabled, for example, when the scheduler lock is held across the
entire lifetime of the RCU read-side critical section.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
When creating sched_domains, stop when we've covered the entire
target span instead of continuing to create domains, only to
later find they're redundant and throw them away again.
This avoids single node systems from touching funny NUMA
sched_domain creation code and reduces the risks of the new
SD_OVERLAP code.
Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Anton Blanchard <anton@samba.org>
Cc: mahesh@linux.vnet.ibm.com
Cc: benh@kernel.crashing.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1311180177.29152.57.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Allow for sched_domain spans that overlap by giving such domains their
own sched_group list instead of sharing the sched_groups amongst
each-other.
This is needed for machines with more than 16 nodes, because
sched_domain_node_span() will generate a node mask from the
16 nearest nodes without regard if these masks have any overlap.
Currently sched_domains have a sched_group that maps to their child
sched_domain span, and since there is no overlap we share the
sched_group between the sched_domains of the various CPUs. If however
there is overlap, we would need to link the sched_group list in
different ways for each cpu, and hence sharing isn't possible.
In order to solve this, allocate private sched_groups for each CPU's
sched_domain but have the sched_groups share a sched_group_power
structure such that we can uniquely track the power.
Reported-and-tested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-08bxqw9wis3qti9u5inifh3y@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In order to prepare for non-unique sched_groups per domain, we need to
carry the cpu_power elsewhere, so put a level of indirection in.
Reported-and-tested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-qkho2byuhe4482fuknss40ad@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Given some common flag combinations, particularly -Os, gcc will inline
rcu_read_unlock_special() despite its being in an unlikely() clause.
Use noinline to prohibit this misoptimization.
In addition, move the second barrier() in __rcu_read_unlock() so that
it is not on the common-case code path. This will allow the compiler to
generate better code for the common-case path through __rcu_read_unlock().
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
The RCU_BOOST commits for TREE_PREEMPT_RCU introduced an other-task
write to a new RCU_READ_UNLOCK_BOOSTED bit in the task_struct structure's
->rcu_read_unlock_special field, but, as noted by Steven Rostedt, without
correctly synchronizing all accesses to ->rcu_read_unlock_special.
This could result in bits in ->rcu_read_unlock_special being spuriously
set and cleared due to conflicting accesses, which in turn could result
in deadlocks between the rcu_node structure's ->lock and the scheduler's
rq and pi locks. These deadlocks would result from RCU incorrectly
believing that the just-ended RCU read-side critical section had been
preempted and/or boosted. If that RCU read-side critical section was
executed with either rq or pi locks held, RCU's ensuing (incorrect)
calls to the scheduler would cause the scheduler to attempt to once
again acquire the rq and pi locks, resulting in deadlock. More complex
deadlock cycles are also possible, involving multiple rq and pi locks
as well as locks from multiple rcu_node structures.
This commit fixes synchronization by creating ->rcu_boosted field in
task_struct that is accessed and modified only when holding the ->lock
in the rcu_node structure on which the task is queued (on that rcu_node
structure's ->blkd_tasks list). This results in tasks accessing only
their own current->rcu_read_unlock_special fields, making unsynchronized
access once again legal, and keeping the rcu_read_unlock() fastpath free
of atomic instructions and memory barriers.
The reason that the rcu_read_unlock() fastpath does not need to access
the new current->rcu_boosted field is that this new field cannot
be non-zero unless the RCU_READ_UNLOCK_BLOCKED bit is set in the
current->rcu_read_unlock_special field. Therefore, rcu_read_unlock()
need only test current->rcu_read_unlock_special: if that is zero, then
current->rcu_boosted must also be zero.
This bug does not affect TINY_PREEMPT_RCU because this implementation
of RCU accesses current->rcu_read_unlock_special with irqs disabled,
thus preventing races on the !SMP systems that TINY_PREEMPT_RCU runs on.
Maybe-reported-by: Dave Jones <davej@redhat.com>
Maybe-reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
PREEMPT_RCU read-side critical sections blocking an expedited grace
period invoke rcu_report_exp_rnp(). When the last such critical section
has completed, rcu_report_exp_rnp() invokes the scheduler to wake up the
task that invoked synchronize_rcu_expedited() -- needlessly holding the
root rcu_node structure's lock while doing so, thus needlessly providing
a way for RCU and the scheduler to deadlock.
This commit therefore releases the root rcu_node structure's lock before
calling wake_up().
Reported-by: Ed Tomlinson <edt@aei.ca>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This change adds a procfs connector event, which is emitted on every
successful process tracer attach or detach.
If some process connects to other one, kernelspace connector reports
process id and thread group id of both these involved processes. On
disconnection null process id is returned.
Such an event allows to create a simple automated userspace mechanism
to be aware about processes connecting to others, therefore predefined
process policies can be applied to them if needed.
Note, a detach signal is emitted only in case, if a tracer process
explicitly executes PTRACE_DETACH request. In other cases like tracee
or tracer exit detach event from proc connector is not reported.
Signed-off-by: Vladimir Zapolskiy <vzapolskiy@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
If the new child is traced, do_fork() adds the pending SIGSTOP.
It assumes that either it is traced because of auto-attach or the
tracer attached later, in both cases sigaddset/set_thread_flag is
correct even if SIGSTOP is already pending.
Now that we have PTRACE_SEIZE this is no longer right in the latter
case. If the tracer does PTRACE_SEIZE after copy_process() makes the
child visible the queued SIGSTOP is wrong.
We could check PT_SEIZED bit and change ptrace_attach() to set both
PT_PTRACED and PT_SEIZED bits simultaneously but see the next patch,
we need to know whether this child was auto-attached or not anyway.
So this patch simply moves this code to ptrace_init_task(), this
way we can never race with ptrace_attach().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
has_stopped_jobs() naively checks task_is_stopped(group_leader). This
was always wrong even without ptrace, group_leader can be dead. And
given that ptrace can change the state to TRACED this is wrong even
in the single-threaded case.
Change the code to check SIGNAL_STOP_STOPPED and simplify the code,
retval + break/continue doesn't make this trivial code more readable.
We could probably add the usual "|| signal->group_stop_count" check
but I don't think this makes sense, the task can start the group-stop
right after the check anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
* pm-domains: (33 commits)
ARM / shmobile: Return -EBUSY from A4LC power off if A3RV is active
PM / Domains: Take .power_off() error code into account
ARM / shmobile: Use genpd_queue_power_off_work()
ARM / shmobile: Use pm_genpd_poweroff_unused()
PM / Domains: Introduce function to power off all unused PM domains
PM / Domains: Queue up power off work only if it is not pending
PM / Domains: Improve handling of wakeup devices during system suspend
PM / Domains: Do not restore all devices on power off error
PM / Domains: Allow callbacks to execute all runtime PM helpers
PM / Domains: Do not execute device callbacks under locks
PM / Domains: Make failing pm_genpd_prepare() clean up properly
PM / Domains: Set device state to "active" during system resume
ARM: mach-shmobile: sh7372 A3RV requires A4LC
PM / Domains: Export pm_genpd_poweron() in header
ARM: mach-shmobile: sh7372 late pm domain off
ARM: mach-shmobile: Runtime PM late init callback
ARM: mach-shmobile: sh7372 D4 support
ARM: mach-shmobile: sh7372 A4MP support
ARM: mach-shmobile: sh7372: make sure that fsi is peripheral of spu2
ARM: mach-shmobile: sh7372 A3SG support
...
This enables pm_notifier_call_chain() to get the actual error code
in the callback rather than always assume -EINVAL by converting all
PM notifier calls to return encapsulate error code with
notifier_from_errno().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Some platforms wish to implement their PM core suspend code as
modules. To do so, these functions need to be exported to modules.
[rjw: Replaced EXPORT_SYMBOL with EXPORT_SYMBOL_GPL]
Reported-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
A system or a device may need to control suspend/wakeup events. It may
want to wakeup the system after a predefined amount of time or at a
predefined event decided while entering suspend for polling or delayed
work. Then, it may want to enter suspend again if its predefined wakeup
condition is the only wakeup reason and there is no outstanding events;
thus, it does not wakeup the userspace unnecessary or unnecessary
devices and keeps suspended as long as possible (saving the power).
Enabling a system to wakeup after a specified time can be easily
achieved by using RTC. However, to enter suspend again immediately
without invoking userland and unrelated devices, we need additional
features in the suspend framework.
Such need comes from:
1. Monitoring a critical device status without interrupts that can
wakeup the system. (in-suspend polling)
An example is ambient temperature monitoring that needs to shut down
the system or a specific device function if it is too hot or cold. The
temperature of a specific device may be needed to be monitored as well;
e.g., a charger monitors battery temperature in order to stop charging
if overheated.
2. Execute critical "delayed work" at suspend.
A driver or a system/board may have a delayed work (or any similar
things) that it wants to execute at the requested time.
For example, some chargers want to check the battery voltage some
time (e.g., 30 seconds) after the battery is fully charged and the
charger has stopped. Then, the charger restarts charging if the voltage
has dropped more than a threshold, which is smaller than "restart-charger"
voltage, which is a threshold to restart charging regardless of the
time passed.
This patch allows to add "suspend_again" callback at struct
platform_suspend_ops and let the "suspend_again" callback return true if
the system is required to enter suspend again after the current instance
of wakeup. Device-wise suspend_again implemented at dev_pm_ops or
syscore is not done because: a) suspend_again feature is usually under
platform-wise decision and controls the behavior of the whole platform
and b) There are very limited devices related to the usage cases of
suspend_again; chargers and temperature sensors are mentioned so far.
With suspend_again callback registered at struct platform_suspend_ops
suspend_ops in kernel/power/suspend.c with suspend_set_ops by the
platform, the suspend framework tries to enter suspend again by
looping suspend_enter() if suspend_again has returned true and there has
been no errors in the suspending sequence or pending wakeups (by
pm_wakeup_pending).
Tested at Exynos4-NURI.
[rjw: Fixed up kerneldoc comment for suspend_enter().]
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu:
rcu: Prevent RCU callbacks from executing before scheduler initialized
Commit 3fe1698b7f ("sched: Deal with non-atomic min_vruntime reads
on 32bit") forgot to initialize min_vruntime_copy which could lead to
an infinite while loop in task_waking_fair() under some circumstances
(early boot, lucky timing).
[ This bug was also reported by others that blamed it on the RCU
initialization problems ]
Reported-and-tested-by: Bruno Wolff III <bruno@wolff.to>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Under some rare but real combinations of configuration parameters, RCU
callbacks are posted during early boot that use kernel facilities that
are not yet initialized. Therefore, when these callbacks are invoked,
hard hangs and crashes ensue. This commit therefore prevents RCU
callbacks from being invoked until after the scheduler is fully up and
running, as in after multiple tasks have been spawned.
It might well turn out that a better approach is to identify the specific
RCU callbacks that are causing this problem, but that discussion will
wait until such time as someone really needs an RCU callback to be invoked
(as opposed to merely registered) during early boot.
Reported-by: julie Sullivan <kernelmail.jms@gmail.com>
Reported-by: RKK <kulkarni.ravi4@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: julie Sullivan <kernelmail.jms@gmail.com>
Tested-by: RKK <kulkarni.ravi4@gmail.com>
This was legacy code brought over from the RT tree and
is no longer necessary.
Signed-off-by: Dima Zavin <dima@android.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Walker <dwalker@codeaurora.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/1310084879-10351-2-git-send-email-dima@android.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This fixes a regression introduced by e59347a "arm: orion:
Use generic irq chip".
Depending on the device, interrupts acknowledgement is done by setting
or by clearing a dedicated register. Replace irq_gc_ack() with some
{set,clr}_bit variants allows to handle both cases.
Note that this patch affects the following SoCs: Davinci, Samsung and
Orion. Except for this last, the change is minor: irq_gc_ack() is just
renamed into irq_gc_ack_set_bit().
For the Orion SoCs, the edge GPIO interrupts support is currently
broken. irq_gc_ack() try to acknowledge a such interrupt by setting
the corresponding cause register bit. The Orion GPIO device expect the
opposite. To fix this issue, the irq_gc_ack_clr_bit() variant is used.
Tested on Network Space v2.
Reported-by: Joey Oravec <joravec@drewtech.com>
Signed-off-by: Simon Guinot <sguinot@lacie.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
There is a bug in free_unnecessary_pages() that causes it to
attempt to free too many pages in some cases, which triggers the
BUG_ON() in memory_bm_clear_bit() for copy_bm. Namely, if
count_data_pages() is initially greater than alloc_normal, we get
to_free_normal equal to 0 and "save" greater from 0. In that case,
if the sum of "save" and count_highmem_pages() is greater than
alloc_highmem, we subtract a positive number from to_free_normal.
Hence, since to_free_normal was 0 before the subtraction and is
an unsigned int, the result is converted to a huge positive number
that is used as the number of pages to free.
Fix this bug by checking if to_free_normal is actually greater
than or equal to the number we're going to subtract from it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@kernel.org
Provides the ability to resize a resource that is already allocated.
This functionality is put in place to support reallocation needs of
pci resources.
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The common clocks management code in drivers/base/power/clock_ops.c
is going to be used during system-wide power transitions as well as
for runtime PM, so it shouldn't depend on CONFIG_PM_RUNTIME.
However, the suspend/resume functions provided by it for
CONFIG_PM_RUNTIME unset, to be used during system-wide power
transitions, should not behave in the same way as their counterparts
defined for CONFIG_PM_RUNTIME set, because in that case the clocks
are managed differently at run time.
The names of the functions still contain the word "runtime" after
this change, but that is going to be modified by a separate patch
later.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Introduce common headers, helper functions and callbacks allowing
platforms to use simple generic power domains for runtime power
management.
Introduce struct generic_pm_domain to be used for representing
power domains that each contain a number of devices and may be
parent domains or subdomains with respect to other power domains.
Among other things, this structure includes callbacks to be
provided by platforms for performing specific tasks related to
power management (i.e. ->stop_device() may disable a device's
clocks, while ->start_device() may enable them, ->power_off() is
supposed to remove power from the entire power domain
and ->power_on() is supposed to restore it).
Introduce functions that can be used as power domain runtime PM
callbacks, pm_genpd_runtime_suspend() and pm_genpd_runtime_resume(),
as well as helper functions for the initialization of a power
domain represented by a struct generic_power_domain object,
adding a device to or removing a device from it and adding or
removing subdomains.
Introduce configuration option CONFIG_PM_GENERIC_DOMAINS to be
selected by the platforms that want to use the new code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Commit c8b28116 ("sched: Increase SCHED_LOAD_SCALE resolution")
intended to have no user-visible effect, but allows setting
cpu.shares to < MIN_SHARES, which the user then sees.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nikhil Rao <ncrao@google.com>
Link: http://lkml.kernel.org/r/1307192600.8618.3.camel@marge.simson.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In this revision the conversion of secid to SELinux context and adding it
to the audit log is moved from xt_AUDIT.c to audit.c with the aid of a
separate helper function - audit_log_secctx - which does both the conversion
and logging of SELinux context, thus also preventing internal secid number
being leaked to userspace. If conversion is not successful an error is raised.
With the introduction of this helper function the work done in xt_AUDIT.c is
much more simplified. It also opens the possibility of this helper function
being used by other modules (including auditd itself), if desired. With this
addition, typical (raw auditd) output after applying the patch would be:
type=NETFILTER_PKT msg=audit(1305852240.082:31012): action=0 hook=1 len=52 inif=? outif=eth0 saddr=10.1.1.7 daddr=10.1.2.1 ipid=16312 proto=6 sport=56150 dport=22 obj=system_u:object_r:ssh_client_packet_t:s0
type=NETFILTER_PKT msg=audit(1306772064.079:56): action=0 hook=3 len=48 inif=eth0 outif=? smac=00:05:5d:7c:27:0b dmac=00:02:b3:0a:7f:81 macproto=0x0800 saddr=10.1.2.1 daddr=10.1.1.7 ipid=462 proto=6 sport=22 dport=3561 obj=system_u:object_r:ssh_server_packet_t:s0
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Mr Dash Four <mr.dash.four@googlemail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
The jump labels entries for modules do not stop at __stop__jump_table,
but after mod->jump_entries + mod_num_jump_entries.
By checking the wrong end point, module trace events never get enabled.
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Jason Baron <jbaron@redhat.com>
Tested-by: Avi Kivity <avi@redhat.com>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/4E00038B.2060404@cn.fujitsu.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently a single process may register exit handlers unlimited times.
It may lead to a bloated listeners chain and very slow process
terminations.
Eg after 10KK sent TASKSTATS_CMD_ATTR_REGISTER_CPUMASKs ~300 Mb of
kernel memory is stolen for the handlers chain and "time id" shows 2-7
seconds instead of normal 0.003. It makes it possible to exhaust all
kernel memory and to eat much of CPU time by triggerring numerous exits
on a single CPU.
The patch limits the number of times a single process may register
itself on a single CPU to one.
One little issue is kept unfixed - as taskstats_exit() is called before
exit_files() in do_exit(), the orphaned listener entry (if it was not
explicitly deregistered) is kept until the next someone's exit() and
implicit deregistration in send_cpu_listeners(). So, if a process
registered itself as a listener exits and the next spawned process gets
the same pid, it would inherit taskstats attributes.
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
wait_consider_task() checks same_thread_group(parent, real_parent),
this is the open-coded ptrace_reparented().
__ptrace_detach() remains the only function which has to check this by
hand, although we could reorganize the code to delay __ptrace_unlink.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Kill real_parent_is_ptracer() and update the callers to use
ptrace_reparented(), after the previous patch they do the same.
Remove the unnecessary ->ptrace != 0 check in get_signal_to_deliver(),
if ptrace_reparented() == T then the task must be ptraced.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
__ptrace_detach() and do_notify_parent() set task->exit_signal = -1
to mark the task dead. This is no longer needed, nobody checks
exit_signal to detect the EXIT_DEAD task.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Upadate the last user of task_detached(), wait_task_zombie(), to
use thread_group_leader() and kill task_detached().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Change reparent_leader() to check ->exit_state instead of ->exit_signal,
this matches the similar EXIT_DEAD check in wait_consider_task() and
allows us to cleanup the do_notify_parent/task_detached logic.
task_detached() was really needed during reparenting before 9cd80bbb
"do_wait() optimization: do not place sub-threads on ->children list"
to filter out the sub-threads. After this change task_detached(p) can
only be true if p is the dead group_leader and its parent ignores
SIGCHLD, in this case the caller of do_notify_parent() is going to
reap this task and it should set EXIT_DEAD.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Change other callers of do_notify_parent() to check the value it
returns, this makes the subsequent task_detached() unnecessary.
Mark do_notify_parent() as __must_check.
Use thread_group_leader() instead of !task_detached() to check
if we need to notify the real parent in wait_task_zombie().
Remove the stale comment in release_task(). "just for sanity" is
no longer true, we have to set EXIT_DEAD to avoid the races with
do_wait().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
