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Tejun Heo 34b087e483 freezer: kill unused set_freezable_with_signal()
There's no in-kernel user of set_freezable_with_signal() left.  Mixing
TIF_SIGPENDING with kernel threads can lead to nasty corner cases as
kernel threads never travel signal delivery path on their own.

e.g. the current implementation is buggy in the cancelation path of
__thaw_task().  It calls recalc_sigpending_and_wake() in an attempt to
clear TIF_SIGPENDING but the function never clears it regardless of
sigpending state.  This means that signallable freezable kthreads may
continue executing with !freezing() && stuck TIF_SIGPENDING, which can
be troublesome.

This patch removes set_freezable_with_signal() along with
PF_FREEZER_NOSIG and recalc_sigpending*() calls in freezer.  User
tasks get TIF_SIGPENDING, kernel tasks get woken up and the spurious
sigpending is dealt with in the usual signal delivery path.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
2011-11-23 09:28:17 -08:00
Tejun Heo adfa543e73 dmatest: don't use set_freezable_with_signal()
Commit 981ed70d8e (dmatest: make dmatest threads freezable) made
dmatest kthread use set_freezable_with_signal(); however, the
interface is scheduled to be removed in the next merge window.

The problem is that unlike userland tasks there's no default place
which handles signal pending state and it isn't clear who owns and/or
is responsible for clearing TIF_SIGPENDING.  For example, in the
current code, try_to_freeze() clears TIF_SIGPENDING but it isn't sure
whether it actually owns the TIF_SIGPENDING nor is it race-free -
ie. the task may continue to run with TIF_SIGPENDING set after the
freezable section.

Unfortunately, we don't have wait_for_completion_freezable_timeout().
This patch open codes it and uses wait_event_freezable_timeout()
instead and removes timeout reloading - wait_event_freezable_timeout()
won't return across freezing events (currently racy but fix scheduled)
and timer doesn't decrement while the task is in freezer.  Although
this does lose timer-reset-over-freezing, given that timeout is
supposed to be long enough and failure to finish inside is considered
irrecoverable, I don't think this is worth the complexity.

While at it, move completion to outer scope and explain that we're
ignoring dangling pointer problem after timeout.  This should give
slightly better chance at avoiding oops after timeout.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
2011-11-23 09:28:16 -08:00
Tejun Heo ec012476af usb_storage: don't use set_freezable_with_signal()
The current implementation of set_freezable_with_signal() is buggy and
tricky to get right.  usb-storage is the only user and its use can be
avoided trivially.

All usb-storage wants is to be able to sleep with timeout and get
woken up if freezing() becomes true.  This can be trivially
implemented by doing interruptible wait w/ freezing() included in the
wait condition.  There's no reason to use set_freezable_with_signal().

Perform interruptible wait on freezing() instead of using
set_freezable_with_signal(), which is scheduled for removal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-21 12:32:26 -08:00
Tejun Heo 839e3407d9 freezer: remove unused @sig_only from freeze_task()
After "freezer: make freezing() test freeze conditions in effect
instead of TIF_FREEZE", freezing() returns authoritative answer on
whether the current task should freeze or not and freeze_task()
doesn't need or use @sig_only.  Remove it.

While at it, rewrite function comment for freeze_task() and rename
@sig_only to @user_only in try_to_freeze_tasks().

This patch doesn't cause any functional change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:26 -08:00
Tejun Heo 37ad8aca94 freezer: use lock_task_sighand() in fake_signal_wake_up()
cgroup_freezer calls freeze_task() without holding tasklist_lock and,
if the task is exiting, its ->sighand may be gone by the time
fake_signal_wake_up() is called.  Use lock_task_sighand() instead of
accessing ->sighand directly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Paul Menage <paul@paulmenage.org>
2011-11-21 12:32:26 -08:00
Tejun Heo 5ece3eae4c freezer: restructure __refrigerator()
If another freeze happens before all tasks leave FROZEN state after
being thawed, the freezer can see the existing FROZEN and consider the
tasks to be frozen but they can clear FROZEN without checking the new
freezing().

Oleg suggested restructuring __refrigerator() such that there's single
condition check section inside freezer_lock and sigpending is cleared
afterwards, which fixes the problem and simplifies the code.
Restructure accordingly.

-v2: Frozen loop exited without releasing freezer_lock.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
2011-11-21 12:32:26 -08:00
Tejun Heo 96ee6d8539 freezer: fix set_freezable[_with_signal]() race
A kthread doing set_freezable*() may race with on-going PM freeze and
the freezer might think all tasks are frozen while the new freezable
kthread is merrily proceeding to execute code paths which aren't
supposed to be executing during PM freeze.

Reimplement set_freezable[_with_signal]() using __set_freezable() such
that freezable PF flags are modified under freezer_lock and
try_to_freeze() is called afterwards.  This eliminates race condition
against freezing.

Note: Separated out from larger patch to resolve fix order dependency
      Oleg pointed out.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:25 -08:00
Tejun Heo 948246f70a freezer: remove should_send_signal() and update frozen()
should_send_signal() is only used in freezer.c.  Exporting them only
increases chance of abuse.  Open code the two users and remove it.

Update frozen() to return bool.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:25 -08:00
Tejun Heo d88e4cb671 freezer: remove now unused TIF_FREEZE
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
2011-11-21 12:32:25 -08:00
Tejun Heo a3201227f8 freezer: make freezing() test freeze conditions in effect instead of TIF_FREEZE
Using TIF_FREEZE for freezing worked when there was only single
freezing condition (the PM one); however, now there is also the
cgroup_freezer and single bit flag is getting clumsy.
thaw_processes() is already testing whether cgroup freezing in in
effect to avoid thawing tasks which were frozen by both PM and cgroup
freezers.

This is racy (nothing prevents race against cgroup freezing) and
fragile.  A much simpler way is to test actual freeze conditions from
freezing() - ie. directly test whether PM or cgroup freezing is in
effect.

This patch adds variables to indicate whether and what type of
freezing conditions are in effect and reimplements freezing() such
that it directly tests whether any of the two freezing conditions is
active and the task should freeze.  On fast path, freezing() is still
very cheap - it only tests system_freezing_cnt.

This makes the clumsy dancing aroung TIF_FREEZE unnecessary and
freeze/thaw operations more usual - updating state variables for the
new state and nudging target tasks so that they notice the new state
and comply.  As long as the nudging happens after state update, it's
race-free.

* This allows use of freezing() in freeze_task().  Replace the open
  coded tests with freezing().

* p != current test is added to warning printing conditions in
  try_to_freeze_tasks() failure path.  This is necessary as freezing()
  is now true for the task which initiated freezing too.

-v2: Oleg pointed out that re-freezing FROZEN cgroup could increment
     system_freezing_cnt.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Paul Menage <paul@paulmenage.org>  (for the cgroup portions)
2011-11-21 12:32:25 -08:00
Tejun Heo 22b4e111fa cgroup_freezer: prepare for removal of TIF_FREEZE
TIF_FREEZE will be removed soon and freezing() will directly test
whether any freezing condition is in effect.  Make the following
changes in preparation.

* Rename cgroup_freezing_or_frozen() to cgroup_freezing() and make it
  return bool.

* Make cgroup_freezing() access task_freezer() under rcu read lock
  instead of task_lock().  This makes the state dereferencing racy
  against task moving to another cgroup; however, it was already racy
  without this change as ->state dereference wasn't synchronized.
  This will be later dealt with using attach hooks.

* freezer->state is now set before trying to push tasks into the
  target state.

-v2: Oleg pointed out that freeze_change_state() was setting
     freeze->state incorrectly to CGROUP_FROZEN instead of
     CGROUP_FREEZING.  Fixed.

-v3: Matt pointed out that setting CGROUP_FROZEN used to always invoke
     try_to_freeze_cgroup() regardless of the current state.  Patch
     updated such that the actual freeze/thaw operations are always
     performed on invocation.  This shouldn't make any difference
     unless something is broken.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:25 -08:00
Tejun Heo 03afed8bc2 freezer: clean up freeze_processes() failure path
freeze_processes() failure path is rather messy.  Freezing is canceled
for workqueues and tasks which aren't frozen yet but frozen tasks are
left alone and should be thawed by the caller and of course some
callers (xen and kexec) didn't do it.

This patch updates __thaw_task() to handle cancelation correctly and
makes freeze_processes() and freeze_kernel_threads() call
thaw_processes() on failure instead so that the system is fully thawed
on failure.  Unnecessary [suspend_]thaw_processes() calls are removed
from kernel/power/hibernate.c, suspend.c and user.c.

While at it, restructure error checking if clause in suspend_prepare()
to be less weird.

-v2: Srivatsa spotted missing removal of suspend_thaw_processes() in
     suspend_prepare() and error in commit message.  Updated.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
2011-11-21 12:32:24 -08:00
Tejun Heo 376fede80e freezer: kill PF_FREEZING
With the previous changes, there's no meaningful difference between
PF_FREEZING and PF_FROZEN.  Remove PF_FREEZING and use PF_FROZEN
instead in task_contributes_to_load().

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:24 -08:00
Tejun Heo 85f1d47665 freezer: test freezable conditions while holding freezer_lock
try_to_freeze_tasks() and thaw_processes() use freezable() and
frozen() as preliminary tests before initiating operations on a task.
These are done without any synchronization and hinder with
synchronization cleanup without any real performance benefits.

In try_to_freeze_tasks(), open code self test and move PF_NOFREEZE and
frozen() tests inside freezer_lock in freeze_task().

thaw_processes() can simply drop freezable() test as frozen() test in
__thaw_task() is enough.

Note: This used to be a part of larger patch to fix set_freezable()
      race.  Separated out to satisfy ordering among dependent fixes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:24 -08:00
Tejun Heo 6907483b4e freezer: make freezing indicate freeze condition in effect
Currently freezing (TIF_FREEZE) and frozen (PF_FROZEN) states are
interlocked - freezing is set to request freeze and when the task
actually freezes, it clears freezing and sets frozen.

This interlocking makes things more complex than necessary - freezing
doesn't mean there's freezing condition in effect and frozen doesn't
match the task actually entering and leaving frozen state (it's
cleared by the thawing task).

This patch makes freezing indicate that freeze condition is in effect.
A task enters and stays frozen if freezing.  This makes PF_FROZEN
manipulation done only by the task itself and prevents wakeup from
__thaw_task() leaking outside of refrigerator.

The only place which needs to tell freezing && !frozen is
try_to_freeze_task() to whine about tasks which don't enter frozen.
It's updated to test the condition explicitly.

With the change, frozen() state my linger after __thaw_task() until
the task wakes up and exits fridge.  This can trigger BUG_ON() in
update_if_frozen().  Work it around by testing freezing() && frozen()
instead of frozen().

-v2: Oleg pointed out missing re-check of freezing() when trying to
     clear FROZEN and possible spurious BUG_ON() trigger in
     update_if_frozen().  Both fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Menage <paul@paulmenage.org>
2011-11-21 12:32:24 -08:00
Tejun Heo 0c9af09262 freezer: use dedicated lock instead of task_lock() + memory barrier
Freezer synchronization is needlessly complicated - it's by no means a
hot path and the priority is staying unintrusive and safe.  This patch
makes it simply use a dedicated lock instead of piggy-backing on
task_lock() and playing with memory barriers.

On the failure path of try_to_freeze_tasks(), locking is moved from it
to cancel_freezing().  This makes the frozen() test racy but the race
here is a non-issue as the warning is printed for tasks which failed
to enter frozen for 20 seconds and race on PF_FROZEN at the last
moment doesn't change anything.

This simplifies freezer implementation and eases further changes
including some race fixes.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:24 -08:00
Tejun Heo 6cd8dedcdd freezer: don't distinguish nosig tasks on thaw
There's no point in thawing nosig tasks before others.  There's no
ordering requirement between the two groups on thaw, which the staged
thawing can't guarantee anyway.  Simplify thaw_processes() by removing
the distinction and collapsing thaw_tasks() into thaw_processes().
This will help further updates to freezer.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:23 -08:00
Tejun Heo a585042f7b freezer: remove racy clear_freeze_flag() and set PF_NOFREEZE on dead tasks
clear_freeze_flag() in exit_mm() is racy.  Freezing can start
afterwards.  Remove it.  Skipping freezer for exiting task will be
properly implemented later.

Also, freezable() was testing exit_state directly to make system
freezer ignore dead tasks.  Let the exiting task set PF_NOFREEZE after
entering TASK_DEAD instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:23 -08:00
Tejun Heo a5be2d0d1a freezer: rename thaw_process() to __thaw_task() and simplify the implementation
thaw_process() now has only internal users - system and cgroup
freezers.  Remove the unnecessary return value, rename, unexport and
collapse __thaw_process() into it.  This will help further updates to
the freezer code.

-v3: oom_kill grew a use of thaw_process() while this patch was
     pending.  Convert it to use __thaw_task() for now.  In the longer
     term, this should be handled by allowing tasks to die if killed
     even if it's frozen.

-v2: minor style update as suggested by Matt.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul Menage <menage@google.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
2011-11-21 12:32:23 -08:00
Tejun Heo 8a32c441c1 freezer: implement and use kthread_freezable_should_stop()
Writeback and thinkpad_acpi have been using thaw_process() to prevent
deadlock between the freezer and kthread_stop(); unfortunately, this
is inherently racy - nothing prevents freezing from happening between
thaw_process() and kthread_stop().

This patch implements kthread_freezable_should_stop() which enters
refrigerator if necessary but is guaranteed to return if
kthread_stop() is invoked.  Both thaw_process() users are converted to
use the new function.

Note that this deadlock condition exists for many of freezable
kthreads.  They need to be converted to use the new should_stop or
freezable workqueue.

Tested with synthetic test case.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Henrique de Moraes Holschuh <ibm-acpi@hmh.eng.br>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-11-21 12:32:23 -08:00
Tejun Heo a0acae0e88 freezer: unexport refrigerator() and update try_to_freeze() slightly
There is no reason to export two functions for entering the
refrigerator.  Calling refrigerator() instead of try_to_freeze()
doesn't save anything noticeable or removes any race condition.

* Rename refrigerator() to __refrigerator() and make it return bool
  indicating whether it scheduled out for freezing.

* Update try_to_freeze() to return bool and relay the return value of
  __refrigerator() if freezing().

* Convert all refrigerator() users to try_to_freeze().

* Update documentation accordingly.

* While at it, add might_sleep() to try_to_freeze().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
2011-11-21 12:32:22 -08:00
Tejun Heo 3a7cbd50f7 freezer: don't unnecessarily set PF_NOFREEZE explicitly
Some drivers set PF_NOFREEZE in their kthread functions which is
completely unnecessary and racy - some part of freezer code doesn't
consider cases where PF_NOFREEZE is set asynchronous to freezer
operations.

In general, there's no reason to allow setting PF_NOFREEZE explicitly.
Remove them and change the documentation to note that setting
PF_NOFREEZE directly isn't allowed.

-v2: Dropped change to twl4030-irq.c as it no longer uses PF_NOFREEZE.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: "Gustavo F. Padovan" <padovan@profusion.mobi>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: wwang <wei_wang@realsil.com.cn>
2011-11-21 12:32:22 -08:00
Tejun Heo 50fb4f7fc9 freezer: fix current->state restoration race in refrigerator()
refrigerator() saves current->state before entering frozen state and
restores it before returning using __set_current_state(); however,
this is racy, for example, please consider the following sequence.

	set_current_state(TASK_INTERRUPTIBLE);
	try_to_freeze();
	if (kthread_should_stop())
		break;
	schedule();

If kthread_stop() races with ->state restoration, the restoration can
restore ->state to TASK_INTERRUPTIBLE after kthread_stop() sets it to
TASK_RUNNING but kthread_should_stop() may still see zero
->should_stop because there's no memory barrier between restoring
TASK_INTERRUPTIBLE and kthread_should_stop() test.

This isn't restricted to kthread_should_stop().  current->state is
often used in memory barrier based synchronization and silently
restoring it w/o mb breaks them.

Use set_current_state() instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-21 12:32:22 -08:00
Linus Torvalds 6fe4c6d466 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (86 commits)
  ipv4: fix redirect handling
  ping: dont increment ICMP_MIB_INERRORS
  sky2: fix hang in napi_disable
  sky2: enforce minimum ring size
  bonding: Don't allow mode change via sysfs with slaves present
  f_phonet: fix page offset of first received fragment
  stmmac: fix pm functions avoiding sleep on spinlock
  stmmac: remove spin_lock in stmmac_ioctl.
  stmmac: parameters auto-tuning through HW cap reg
  stmmac: fix advertising 1000Base capabilties for non GMII iface
  stmmac: use mdelay on timeout of sw reset
  sky2: version 1.30
  sky2: used fixed RSS key
  sky2: reduce default Tx ring size
  sky2: rename up/down functions
  sky2: pci posting issues
  sky2: fix hang on shutdown (and other irq issues)
  r6040: fix check against MCRO_HASHEN bit in r6040_multicast_list
  MAINTAINERS: change email address for shemminger
  pch_gbe: Move #include of module.h
  ...
2011-11-20 14:59:33 -08:00
Linus Torvalds a4cc3889f7 Merge branch 'kvm-updates/3.2' of git://git.kernel.org/pub/scm/virt/kvm/kvm
* 'kvm-updates/3.2' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM guest: prevent tracing recursion with kvmclock
  Revert "KVM: PPC: Add support for explicit HIOR setting"
  KVM: VMX: Check for automatic switch msr table overflow
  KVM: VMX: Add support for guest/host-only profiling
  KVM: VMX: add support for switching of PERF_GLOBAL_CTRL
  KVM: s390: announce SYNC_MMU
  KVM: s390: Fix tprot locking
  KVM: s390: handle SIGP sense running intercepts
  KVM: s390: Fix RUNNING flag misinterpretation
2011-11-20 14:57:43 -08:00
Linus Torvalds bb893d15b5 Merge branch 'fixes' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm
* 'fixes' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm:
  ARM: wire up process_vm_writev and process_vm_readv syscalls
  ARM: 7160/1: setup: avoid overflowing {elf,arch}_name from proc_info_list
  ARM: 7158/1: add new MFP implement for NUC900
  ARM: 7157/1: fix a building WARNING for nuc900
  ARM: 7156/1: l2x0: fix compile error on !CONFIG_USE_OF
  ARM: 7155/1: arch.h: Declare 'pt_regs' locally
  ARM: 7154/1: mach-bcmring: fix build error in dma.c
  ARM: 7153/1: mach-bcmring: fix build error in core.c
  ARM: 7152/1: distclean: Remove generated .dtb files
  ARM: 7150/1: Allow kernel unaligned accesses on ARMv6+ processors
  ARM: 7149/1: spi/pl022: Enable clock in probe
  Revert "ARM: 7098/1: kdump: copy kernel relocation code at the kexec prepare stage"
2011-11-20 14:34:58 -08:00
Linus Torvalds 2d360fcbd8 Merge branch 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / Suspend: Fix bug in suspend statistics update
  PM / Hibernate: Fix the early termination of test modes
  PM / shmobile: Fix build of sh7372_pm_init() for CONFIG_PM unset
  PM Sleep: Do not extend wakeup paths to devices with ignore_children set
  PM / driver core: disable device's runtime PM during shutdown
  PM / devfreq: correct Kconfig dependency
  PM / devfreq: fix use after free in devfreq_remove_device
  PM / shmobile: Avoid restoring the INTCS state during initialization
  PM / devfreq: Remove compiler error after irq.h update
  PM / QoS: Properly use the WARN() macro in dev_pm_qos_add_request()
  PM / Clocks: Only disable enabled clocks in pm_clk_suspend()
  ARM: mach-shmobile: sh7372 A3SP no_suspend_console fix
  PM / shmobile: Don't skip debugging output in pd_power_up()
2011-11-20 14:33:02 -08:00
Avi Kivity 95ef1e5292 KVM guest: prevent tracing recursion with kvmclock
Prevent tracing of preempt_disable() in get_cpu_var() in
kvm_clock_read(). When CONFIG_DEBUG_PREEMPT is enabled,
preempt_disable/enable() are traced and this causes the function_graph
tracer to go into an infinite recursion. By open coding the
preempt_disable() around the get_cpu_var(), we can use the notrace
version which prevents preempt_disable/enable() from being traced and
prevents the recursion.

Based on a similar patch for Xen from Jeremy Fitzhardinge.

Tested-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-11-20 10:53:48 +02:00
Linus Torvalds a767835f6d Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (exynos4_tmu) Fix Kconfig dependency

[ Merging code in-flight, just because I can.  What timezone should I
  use?  - Linus ]
2011-11-19 10:56:01 -08:00
Srivatsa S. Bhat 501a708f18 PM / Suspend: Fix bug in suspend statistics update
After commit 2a77c46de1
(PM / Suspend: Add statistics debugfs file for suspend to RAM)
a missing pair of braces inside the state_store() function causes even
invalid arguments to suspend to be wrongly treated as failed suspend
attempts. Fix this.

[rjw: Put the hash/subject of the buggy commit into the changelog.]

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-11-19 14:37:57 +01:00
Jeremy Fitzhardinge d633180c20 Xen: update MAINTAINER info
No longer at Citrix, still interested in Xen.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-19 06:21:38 -05:00
David Rientjes a5c86e986f hugetlb: remove dummy definitions of HPAGE_MASK and HPAGE_SIZE
Dummy, non-zero definitions for HPAGE_MASK and HPAGE_SIZE were added in
51c6f666fc ("mm: ZAP_BLOCK causes redundant work") to avoid a divide
by zero in generic kernel code.

That code has since been removed, but probably should never have been
added in the first place: we don't want HPAGE_SIZE to act like PAGE_SIZE
for code that is working with hugepages, for example, when the
dependency on CONFIG_HUGETLB_PAGE has not been fulfilled.

Because hugepage size can differ from architecture to architecture, each
is required to have their own definitions for both HPAGE_MASK and
HPAGE_SIZE.  This is always done in arch/*/include/asm/page.h.

So, just remove the dummy and dangerous definitions since they are no
longer needed and reveals the correct dependencies.  Tested on
architectures using the definitions with allyesconfig: x86 (even with
thp), hppa, mips, powerpc, s390, sh3, sh4, sparc, and sparc64, and with
defconfig on ia64.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-19 06:15:59 -05:00
Linus Torvalds 208f6f6068 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  new helper: mount_subtree()
  switch create_mnt_ns() to saner calling conventions, fix double mntput() in nfs
  btrfs: fix double mntput() in mount_subvol()
2011-11-19 06:06:39 -05:00
Linus Torvalds ab5c5f639b Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  MAINTAINERS: update XFS maintainer entry
  xfs: use doalloc flag in xfs_qm_dqattach_one()
2011-11-19 06:05:17 -05:00
Linus Torvalds c5e0c7825d Merge branch 'for-3.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
* 'for-3.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: Replace Paul Menage with Tejun Heo as cgroups maintainer
2011-11-18 22:23:23 -02:00
Linus Torvalds 5c6b4e84cb Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  random: Fix handing of arch_get_random_long in get_random_bytes()
  x86: Call stop_machine_text_poke() on all CPUs
  x86, ioapic: Only print ioapic debug information for IRQs belonging to an ioapic chip
  x86/mrst: Avoid reporting wrong nmi status
  x86/mrst: Add support for Penwell clock calibration
  x86/apic: Allow use of lapic timer early calibration result
  x86/apic: Do not clear nr_irqs_gsi if no legacy irqs
  x86/platform: Add a wallclock_init func to x86_platforms ops
  x86/mce: Make mce_chrdev_ops 'static const'
2011-11-18 22:16:18 -02:00
Linus Torvalds ddddefa99d Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide:
  cy82c693: fix PCI device selection
  icside: DMA support fix
  IDE: Don't powerdown Compaq Triflex IDE device on suspend
  piix: ICH7 MWDMA1 errata
2011-11-18 22:04:12 -02:00
Linus Torvalds e27fc7e476 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: Patch sun4v code sequences properly on module load.
  sparc: Kill custom io_remap_pfn_range().
  sparc: Stash orig_i0 into %g6 instead of %g2
  sparc: Fix handling of orig_i0 wrt. debugging when restarting syscalls.
  sparc: sigutil: Include <linux/errno.h>
2011-11-18 22:03:31 -02:00
Paul Menage 860ca0e6f7 cgroup: Replace Paul Menage with Tejun Heo as cgroups maintainer
As is probably painfully obvious, I don't have time to be a cgroups
maintainer.  Rather than have me continue to hope that I'll magically
find more spare time, instead Tejun has kindly agreed to take over the
role, along with Li Zefan.

-tj: added cgroup tree URL to MAINTAINERS file

Signed-off-by: Paul Menage <paul@paulmenage.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <1321320612-57855-1-git-send-email-paul@paulmenage.org>
2011-11-18 14:28:40 -08:00
Srivatsa S. Bhat aa9a7b1182 PM / Hibernate: Fix the early termination of test modes
Commit 2aede851dd
(PM / Hibernate: Freeze kernel threads after preallocating memory)
postponed the freezing of kernel threads to after preallocating memory
for hibernation. But while doing that, the hibernation test TEST_FREEZER
and the test mode HIBERNATION_TESTPROC were not moved accordingly.

As a result, when using these test modes, it only goes upto the freezing of
userspace and exits, when in fact it should go till the complete end of task
freezing stage, namely the freezing of kernel threads as well.

So, move these points of exit to appropriate places so that freezing of
kernel threads is also tested while using these test harnesses.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-11-18 23:02:42 +01:00
Eric Dumazet 9cc20b268a ipv4: fix redirect handling
commit f39925dbde (ipv4: Cache learned redirect information in
inetpeer.) introduced a regression in ICMP redirect handling.

It assumed ipv4_dst_check() would be called because all possible routes
were attached to the inetpeer we modify in ip_rt_redirect(), but thats
not true.

commit 7cc9150ebe (route: fix ICMP redirect validation) tried to fix
this but solution was not complete. (It fixed only one route)

So we must lookup existing routes (including different TOS values) and
call check_peer_redir() on them.

Reported-by: Ivan Zahariev <famzah@icdsoft.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Flavio Leitner <fbl@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-18 15:24:32 -05:00
Alex Elder c889132913 MAINTAINERS: update XFS maintainer entry
I will no longer be maintaining XFS for SGI.  Ben Myers
(bpm@sgi.com) has agreed to be the primary maintainer
for XFS in my place.  I will continue to be able to push
commits to the SGI XFS tree if required.  As such I will
continue to be a designated XFS maintainer, but plan to
serve in more of a backup role.

Signed-off-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2011-11-18 14:09:23 -06:00
Eric Dumazet fb120c0a27 ping: dont increment ICMP_MIB_INERRORS
ping module incorrectly increments ICMP_MIB_INERRORS if feeded with a
frame not belonging to its own sockets.

RFC 2011 states that ICMP_MIB_INERRORS should count "the number of ICMP
messages which the entiry received but determined as having
ICMP-specific errors (bad ICMP checksums, bad length, etc.)."

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Flavio Leitner <fbl@redhat.com>
Acked-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-18 14:38:59 -05:00
Linus Torvalds b684452383 Merge branch 'stable/for-linus-fixes-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
* 'stable/for-linus-fixes-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen-gntalloc: signedness bug in add_grefs()
  xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()
  xen-gntdev: integer overflow in gntdev_alloc_map()
  xen:pvhvm: enable PVHVM VCPU placement when using more than 32 CPUs.
  xen/balloon: Avoid OOM when requesting highmem
  xen: Remove hanging references to CONFIG_XEN_PLATFORM_PCI
  xen: map foreign pages for shared rings by updating the PTEs directly
2011-11-18 13:18:07 -02:00
Linus Torvalds 15bd1cfb30 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
* 'for-linus' of git://git.kernel.dk/linux-block:
  block: add missed trace_block_plug
  paride: fix potential information leak in pg_read()
  bio: change some signed vars to unsigned
  block: avoid unnecessary plug list flush
  cciss: auto engage SCSI mid layer at driver load time
  loop: cleanup set_status interface
  include/linux/bio.h: use a static inline function for bio_integrity_clone()
  loop: prevent information leak after failed read
  block: Always check length of all iov entries in blk_rq_map_user_iov()
  The Windows driver .inf disables ASPM on all cciss devices. Do the same.
  backing-dev: ensure wakeup_timer is deleted
  block: Revert "[SCSI] genhd: add a new attribute "alias" in gendisk"
2011-11-18 09:34:35 -02:00
Linus Torvalds 9545eb61e5 Merge branch 'unicore32' of git://github.com/gxt/linux
* 'unicore32' of git://github.com/gxt/linux:
  unicore32, exec: remove redundant set_fs(USER_DS)
  unicore32: Fix typo 'PUV3_I2C'
  unicore32: drop unused Kconfig symbols
  rtc: rtc-puv3: Add __devinit and __devexit markers for probe and remove
  arch/unicore32: do not use EXTRA_AFLAGS or EXTRA_CFLAGS
  unicore32: fix build error for find bitops
2011-11-18 07:51:57 -02:00
Linus Torvalds 148b00b63a Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/signal32: Fix sigset_t conversion when copying to user
  powerpc: Fix atomic_xxx_return barrier semantics
  powerpc: Remove buggy 9-year-old test for binutils < 2.12.1
  powerpc/book3e-64: Fix debug support for userspace
  powerpc: Remove extraneous CONFIG_PPC_ADV_DEBUG_REGS define
  powerpc: Revert show_regs() define for readability
  powerpc/ps3: Fix SMP lockdep boot warning
  powerpc/ps3: Fix lost SMP IPIs
  powerpc: Add hvcall.h include to book3s_hv.c
  powerpc/trace: Add a dummy stack frame for trace_hardirqs_off
  powerpc: Copy down exception vectors after feature fixups
  powerpc: panic if we can't instantiate RTAS
  powerpc/4xx: Fix typos in kexec config dependencies
  powerpc/fsl: MCU_MPC8349EMITX wants I2C built-in, modular won't do...
  powerpc/fsl_udc_core: Fix dumb typo
  carma-fpga: Missed switch from of_register_platform_driver()
  powerpc: Fix build breakage in jump_label.c
2011-11-18 07:16:10 -02:00
Linus Torvalds e36d5058db Merge branch 'for-linus' of git://git.selinuxproject.org/~jmorris/linux-security
* 'for-linus' of git://git.selinuxproject.org/~jmorris/linux-security:
  encrypted-keys: module build fixes
  encrypted-keys: fix error return code
  Smack: smackfs cipso seq read repair
2011-11-18 07:14:30 -02:00
David S. Miller 0b64120cce sparc64: Patch sun4v code sequences properly on module load.
Some of the sun4v code patching occurs in inline functions visible
to, and usable by, modules.

Therefore we have to patch them up during module load.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-17 22:44:58 -08:00
stephen hemminger 282edcece3 sky2: fix hang in napi_disable
If IRQ was never initialized, then calling napi_disable() would hang.
Add more bookkeeping to track whether IRQ was ever initialized.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-17 21:43:57 -05:00