move_task_off_dead_cpu()->select_fallback_rq() reads/updates ->cpus_allowed
lockless. We can race with set_cpus_allowed() running in parallel.

Change it to take rq->lock around select_fallback_rq(). Note that it is not
trivial to move this spin_lock() into select_fallback_rq(), we must recheck
the task was not migrated after we take the lock and other callers do not
need this lock.

To avoid the races with other callers of select_fallback_rq() which rely on
TASK_WAKING, we also check p->state != TASK_WAKING and do nothing otherwise.
The owner of TASK_WAKING must update ->cpus_allowed and choose the correct
CPU anyway, and the subsequent __migrate_task() is just meaningless because
p->se.on_rq must be false.

Alternatively, we could change select_task_rq() to take rq->lock right
after it calls sched_class->select_task_rq(), but this looks a bit ugly.

Also, change it to not assume irqs are disabled and absorb __migrate_task_irq().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100315091010.GA9131@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

This patch just states the fact the cpusets/cpuhotplug interaction is
broken and removes the deadlockable code which only pretends to work.

- cpuset_lock() doesn't really work. It is needed for
  cpuset_cpus_allowed_locked() but we can't take this lock in
  try_to_wake_up()->select_fallback_rq() path.

- cpuset_lock() is deadlockable. Suppose that a task T bound to CPU takes
  callback_mutex. If cpu_down(CPU) happens before T drops callback_mutex
  stop_machine() preempts T, then migration_call(CPU_DEAD) tries to take
  cpuset_lock() and hangs forever because CPU is already dead and thus
  T can't be scheduled.

- cpuset_cpus_allowed_locked() is deadlockable too. It takes task_lock()
  which is not irq-safe, but try_to_wake_up() can be called from irq.

Kill them, and change select_fallback_rq() to use cpu_possible_mask, like
we currently do without CONFIG_CPUSETS.

Also, with or without this patch, with or without CONFIG_CPUSETS, the
callers of select_fallback_rq() can race with each other or with
set_cpus_allowed() pathes.

The subsequent patches try to to fix these problems.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100315091003.GA9123@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

USER_SCHED has been removed, so update the documentation
accordingly.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
LKML-Reference: <4BA9A07E.8070508@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

This is left over from commit 7c941438 ("sched: Remove USER_SCHED"")
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Dhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Howells <dhowells@redhat.com>
LKML-Reference: <4BA9A05F.7010407@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge reason: update to latest upstream
Signed-off-by: Ingo Molnar <mingo@elte.hu>

* 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (76 commits)
  drm/radeon/kms: enable ACPI powermanagement mode on radeon gpus.
  drm/radeon/kms: rs400/480 should set common registers.
  drm/radeon/kms: add sanity check to wptr.
  drm/radeon/kms/evergreen: get DP working
  drm/radeon/kms: add hw_i2c module option
  drm/radeon/kms: use new pre/post_xfer i2c bit algo hooks
  drm/radeon/kms: disable MSI on IGP chips
  drm/radeon/kms: display watermark updates (v2)
  drm/radeon/kms/dp: disable training pattern on the sink at the end of link training
  drm/radeon/kms: minor fixes for eDP with LCD* device tags (v2)
  drm/radeon/kms/dp: remove extraneous training complete call
  drm/radeon/kms/atom: minor fixes to transmitter setup
  drm/radeon/kms: Only restrict BO to visible VRAM size when pinning to VRAM.
  drm: fix build error when SYSRQ is disabled
  drm/radeon/kms: fix macbookpro connector quirk
  drm/radeon/r6xx/r7xx: further safe reg clean up
  drm/radeon: bump the UMS driver version for r6xx/r7xx const buffer support
  drm/radeon/kms: bump the version for r6xx/r7xx const buffer support
  drm/radeon/r6xx/r7xx: CS parser fixes
  drm/radeon/kms: fix some typos in r6xx/r7xx hpd setup
  ...

Fix up MSI-related conflicts in drivers/gpu/drm/radeon/radeon_irq_kms.c

* 'for-linus' of git://git.monstr.eu/linux-2.6-microblaze: (35 commits)
  microblaze: Support word copying in copy_tofrom_user
  microblaze: Print early printk information to log buffer
  microblaze: head.S typo fix
  microblaze: Use MICROBLAZE_TLB_SIZE in asm code
  microblaze: Kconfig Fix - pci
  microblaze: Adding likely macros
  microblaze: Add .type and .size to ASM functions
  microblaze: Fix TLB macros
  microblaze: Use instruction with delay slot
  microblaze: Remove additional resr and rear loading
  microblaze: Change register usage for ESR and EAR
  microblaze: Prepare work for optimization in exception code
  microblaze: Add DEBUG option
  microblaze: Support systems without lmb bram
  microblaze: uaccess: Sync strlen, strnlen, copy_to/from_user
  microblaze: uaccess: Unify __copy_tofrom_user
  microblaze: uaccess: Move functions to generic location
  microblaze: uaccess: Fix put_user for noMMU
  microblaze: uaccess: Fix get_user macro for noMMU
  microblaze: uaccess: fix clear_user for noMMU kernel
  ...

Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mjg59/platform-drivers-x86

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mjg59/platform-drivers-x86:
  eeepc-wmi: new driver for WMI based hotkeys on Eee PC laptops
  asus-laptop: fix warning in asus_handle_init

proc_oom_score(task) has a reference to task_struct, but that is all.
If this task was already released before we take tasklist_lock

	- we can't use task->group_leader, it points to nowhere

	- it is not safe to call badness() even if this task is
	  ->group_leader, has_intersects_mems_allowed() assumes
	  it is safe to iterate over ->thread_group list.

	- even worse, badness() can hit ->signal == NULL

Add the pid_alive() check to ensure __unhash_process() was not called.

Also, use "task" instead of task->group_leader. badness() should return
the same result for any sub-thread. Currently this is not true, but
this should be changed anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Word copying is used only for aligned addresses.
Here is space for improving to use any better copying technique.
Look at memcpy implementation.
Signed-off-by: Michal Simek <monstr@monstr.eu>

If early printk console is not enabled then all messages
are written to log buffer.
Signed-off-by: Michal Simek <monstr@monstr.eu>

I forget to change register name in comments.
Signed-off-by: Michal Simek <monstr@monstr.eu>

TLB size was hardcoded in asm code. This patch brings ability
to change TLB size only in one place. (mmu.h).
Signed-off-by: Michal Simek <monstr@monstr.eu>

I forget to remove pci Kconfig option.
Signed-off-by: Michal Simek <monstr@monstr.eu>

On the base on GCOV analytics is helpful to add likely/unlikely
macros.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Cachegrind analysis need this fix to be able to log asm functions.
Signed-off-by: Michal Simek <monstr@monstr.eu>

To be able to do trace TLB operations.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Sync labels.
Signed-off-by: Michal Simek <monstr@monstr.eu>

RESR and REAR uses the same regs in whole file.
Signed-off-by: Michal Simek <monstr@monstr.eu>

This change synchronize register usage in code.
ESR = R4
EAR = R3
Signed-off-by: Michal Simek <monstr@monstr.eu>

Any sync branch must follow mts instructions not mfs.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Disable debug option in asm code.
Signed-off-by: Michal Simek <monstr@monstr.eu>

When the system has no lmb bram, main memory should be start from
zero because of microblaze vectors.

DTS fragment could look like:
	DDR2_SDRAM: memory@0 {
		device_type = "memory";
		reg = < 0x0 0x10000000 >;
	} ;

Then you have to setup CONFIG_KERNEL_BASE_ADDR=0 which caused
that kernel physical start address will be zero. On reset vector place
will be jump to 0x100 and on 0x100 starts kernel text.

You have to solve how to load the kernel before cpu starts.
Tested with XMD.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Last sync.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Move to generic location.
Signed-off-by: Michal Simek <monstr@monstr.eu>

noMMU and MMU use them.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Here is small regression on dhrystone tests and I think
that on all benchmarking tests. It is due to better checking
mechanism in put_user macro
Signed-off-by: Michal Simek <monstr@monstr.eu>

Use unified version.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Previous patches fixed only MMU version and this is the first
patch for noMMU kernel
Signed-off-by: Michal Simek <monstr@monstr.eu>

Generic implementation for noMMU and MMU version
Signed-off-by: Michal Simek <monstr@monstr.eu>

copy_from_user macro also use copy_tofrom_user function
Signed-off-by: Michal Simek <monstr@monstr.eu>

noMMU and MMU kernel will use copy copy_tofrom_user
asm implementation.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Add macro description and resort.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Use FIXUP macros and resort them.
Signed-off-by: Michal Simek <monstr@monstr.eu>

It is used __FIXUP_SECTION and __EX_TABLE_SECTION macros.
Signed-off-by: Michal Simek <monstr@monstr.eu>

This is the first patch which does uaccess unification.
I choosed to do several patches to be able to use bisect
in future if any fault happens.
Signed-off-by: Michal Simek <monstr@monstr.eu>

The same noMMU and MMU functions should be placed in
one file.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Just sort to be able remove whole block.
Signed-off-by: Michal Simek <monstr@monstr.eu>

I would like to use asm-generic uaccess.h where are segment
macros defined. This is just first step.
Signed-off-by: Michal Simek <monstr@monstr.eu>

We don't need to do it.
Signed-off-by: Michal Simek <monstr@monstr.eu>