This adds the appropriate pointer to all the internal (i.e.  static)
functions that work with global acct instance.  API calls pass a global
instance to them (while we still have such).

Mostly this is a s/acct_globals./acct->/ over the file.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Don't use per-bsd-acct-struct lock, but work with a global one.

This lock is taken for short periods, so it doesn't seem it'll become a
bottleneck, but it will allow us to easily avoid many locking difficulties
in the future.

So this is a mostly s/acct_globals.lock/acct_lock/ over the file.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We're going to have many bsd_acct_struct instances, not just one, so the
timer (currently working with a global one) has to know which one to work
with.

Use a handy setup_timer macro for it (thanks to Oleg for one).
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The acct_process does not accept any arguments actually.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It makes many fields initialization implicit helping in auto-setting
#ifdef-ed fields (bsd-acct related pointer will be such).
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After I fixed access to task->tgid in kernel/acct.c, Oleg pointed out some
bad side effects with this accounting vs pid namespaces interaction.  I.e.
 when some task in pid namespace sets this accounting up, this blocks all
the others from doing the same.  Restricting this to init namespace only
could help, but didn't look a graceful solution.

So here is the approach to make this accounting work with pid namespaces
properly.

The idea is simple - when a task dies it accounts itself in each namespace
it is visible from and which set the accounting up.

For example here are the commands run and the output of lastcomm from init
and sub namespaces:

init_ns# accton pacct
 sub_ns# accton pacct (this is a different file - sub ns is run in
                       a chroot-ed environment)
init_ns# cat /dev/null
 sub_ns# ls /dev/null
init_ns# accton
 sub_ns# accton

 sub_ns#  lastcomm -f pacct
ls                      0        [136,0]    0.00 secs Thu May 15 10:30
accton                  0        [136,0]    0.00 secs Thu May 15 10:30

init_ns# lastcomm -f pacct
accton                  root     pts/0      0.00 secs Thu May 15 14:30 << got from sub
cat                     root     pts/1      0.00 secs Thu May 15 14:30
ls                      root     pts/0      0.00 secs Thu May 15 14:30 << got from sub
accton                  root     pts/1      0.00 secs Thu May 15 14:30

That was the summary, the details are in patches.

This patch:

It will be visible in pid_namespace.h file, so fix its name to look better
outside the acct.c file.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Adapt acct_update_integrals() to include user time when calculating the time
difference.  The units of acct_rss_mem1 and acct_vm_mem1 are also changed from
pages-jiffies to pages-usecs to avoid calling jiffies_to_usecs() in
xacct_add_tsk() which might overflow.
Signed-off-by: NJonathan Lim <jlim@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the removal of the Solaris binary emulation the export of
uts_sem became unused.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/trace/trace_sysprof.c:164:20: warning: Using plain integer as NULL pointer
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

rcu_barrier_sched() and call_rcu_sched() were introduced in 2.6.26 for the
Markers.  Change the marker code to use them.

It can be seen as a fix since the marker code was using an ugly,
temporary, #ifdef hack to work around CONFIG_PREEMPT_RCU.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: NPaul McKenney <paulmck@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This one had the only users so far - the kill_proc, which is removed, so
drop this (invalid in namespaced world) call too.

And of course - erase all references on it from comments.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This function operated on a pid_t to kill a task, which is no longer valid
in a containerized system.

It has finally lost all its users and we can safely remove it from the
tree.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Catch, e. g., 644/0644 typo.
Signed-off-by: NAlexey Dobriyan <adobriyan@parallels.com>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move EXPORT_SYMBOL right after the func
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The bug was pointed out by Akinobu Mita <akinobu.mita@gmail.com>, and this
patch is based on his original patch.

workqueue_cpu_callback(CPU_UP_PREPARE) expects that if it returns
NOTIFY_BAD, _cpu_up() will send CPU_UP_CANCELED then.

However, this is not true since

	"cpu hotplug: cpu: deliver CPU_UP_CANCELED only to NOTIFY_OKed callbacks with CPU_UP_PREPARE"
	commit: a0d8cdb6

The callback which has returned NOTIFY_BAD will not receive
CPU_UP_CANCELED.  Change the code to fulfil the CPU_UP_CANCELED logic if
CPU_UP_PREPARE fails.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Reported-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

schedule_on_each_cpu() can use schedule_work_on() to avoid the code
duplication.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

queue_work() can use queue_work_on() to avoid the code duplication.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add lockdep annotations to flush_work() and update the comment.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Jarek Poplawski <jarkao2@o2.pl>
Acked-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

workqueue_cpu_callback(CPU_DEAD) flushes cwq->thread under
cpu_maps_update_begin().  This means that the multithreaded workqueues
can't use get_online_cpus() due to the possible deadlock, very bad and
very old problem.

Introduce the new state, CPU_POST_DEAD, which is called after
cpu_hotplug_done() but before cpu_maps_update_done().

Change workqueue_cpu_callback() to use CPU_POST_DEAD instead of CPU_DEAD.
This means that create/destroy functions can't rely on get_online_cpus()
any longer and should take cpu_add_remove_lock instead.

[akpm@linux-foundation.org: fix CONFIG_SMP=n]
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NGautham R Shenoy <ego@in.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Paul Menage <menage@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change schedule_on_each_cpu() to use flush_work() instead of
flush_workqueue(), this way we don't wait for other work_struct's which
can be queued meanwhile.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Jarek Poplawski <jarkao2@gmail.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Most of users of flush_workqueue() can be changed to use cancel_work_sync(),
but sometimes we really need to wait for the completion and cancelling is not
an option. schedule_on_each_cpu() is good example.

Add the new helper, flush_work(work), which waits for the completion of the
specific work_struct. More precisely, it "flushes" the result of of the last
queue_work() which is visible to the caller.

For example, this code

	queue_work(wq, work);
	/* WINDOW */
	queue_work(wq, work);

	flush_work(work);

doesn't necessary work "as expected". What can happen in the WINDOW above is

	- wq starts the execution of work->func()

	- the caller migrates to another CPU

now, after the 2nd queue_work() this work is active on the previous CPU, and
at the same time it is queued on another. In this case flush_work(work) may
return before the first work->func() completes.

It is trivial to add another helper

	int flush_work_sync(struct work_struct *work)
	{
		return flush_work(work) || wait_on_work(work);
	}

which works "more correctly", but it has to iterate over all CPUs and thus
it much slower than flush_work().
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NMax Krasnyansky <maxk@qualcomm.com>
Acked-by: NJarek Poplawski <jarkao2@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

insert_work() inserts the new work_struct before or after cwq->worklist,
depending on the "int tail" parameter. Change it to accept "list_head *"
instead, this shrinks .text a bit and allows us to insert the barrier
after specific work_struct.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Jarek Poplawski <jarkao2@gmail.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that we have core_state->dumper list we can use it to wake up the
sub-threads waiting for the coredump completion.

This uglifies the code and .text grows by 47 bytes, but otoh mm_struct
lessens by sizeof(struct completion).  Also, with this change we can
decouple exit_mm() from the coredumping code.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

binfmt->core_dump() has to iterate over the all threads in system in order
to find the coredumping threads and construct the list using the
GFP_ATOMIC allocations.

With this patch each thread allocates the list node on exit_mm()'s stack and
adds itself to the list.

This allows us to do further changes:

	- simplify ->core_dump()

	- change exit_mm() to clear ->mm first, then wait for ->core_done.
	  this makes the coredumping process visible to oom_kill

	- kill mm->core_done
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Turn core_state->nr_threads into atomic_t and kill now unneeded
down_write(&mm->mmap_sem) in exit_mm().
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move mm->core_waiters into "struct core_state" allocated on stack.  This
shrinks mm_struct a little bit and allows further changes.

This patch mostly does s/core_waiters/core_state.  The only essential
change is that coredump_wait() must clear mm->core_state before return.

The coredump_wait()'s path is uglified and .text grows by 30 bytes, this
is fixed by the next patch.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm->core_startup_done points to "struct completion startup_done" allocated
on the coredump_wait()'s stack.  Introduce the new structure, core_state,
which holds this "struct completion".  This way we can add more info
visible to the threads participating in coredump without enlarging
mm_struct.

No changes in affected .o files.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Kill PF_BORROWED_MM.  Change use_mm/unuse_mm to not play with ->flags, and
do s/PF_BORROWED_MM/PF_KTHREAD/ for a couple of other users.

No functional changes yet.  But this allows us to do further
fixes/cleanups.

oom_kill/ptrace/etc often check "p->mm != NULL" to filter out the
kthreads, this is wrong because of use_mm().  The problem with
PF_BORROWED_MM is that we need task_lock() to avoid races.  With this
patch we can check PF_KTHREAD directly, or use a simple lockless helper:

	/* The result must not be dereferenced !!! */
	struct mm_struct *__get_task_mm(struct task_struct *tsk)
	{
		if (tsk->flags & PF_KTHREAD)
			return NULL;
		return tsk->mm;
	}

Note also ecard_task().  It runs with ->mm != NULL, but it's the kernel
thread without PF_BORROWED_MM.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce the new PF_KTHREAD flag to mark the kernel threads.  It is set
by INIT_TASK() and copied to the forked childs (we could set it in
kthreadd() along with PF_NOFREEZE instead).

daemonize() was changed as well.  In that case testing of PF_KTHREAD is
racy, but daemonize() is hopeless anyway.

This flag is cleared in do_execve(), before search_binary_handler().
Probably not the best place, we can do this in exec_mmap() or in
start_thread(), or clear it along with PF_FORKNOEXEC.  But I think this
doesn't matter in practice, and if do_execve() fails kthread should die
soon.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

1. SIGKILL can't be blocked, remove this check from sigkill_pending().

2. When ptrace_stop() sees sigkill_pending() == T, it can just return.
   Kill "int killed" and simplify the code. This also is more correct,
   the tracer shouldn't see us in TASK_TRACED if we are not going to
   stop.

I strongly believe this code needs further changes.  We should do the "was
this task killed" check unconditionally, currently it depends on
arch_ptrace_stop_needed().  On the other hand, sigkill_pending() isn't
very clever.  If the task was killed tkill(SIGKILL), the signal can be
already dequeued if the caller is do_exit().
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change the type of pid and tgid variables from int to the POSIX type
pid_t.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In the switch to configurable HZ in 2.6, the treatment of the si_utime and
si_stime fields that are exposed to userland via the siginfo structure
looks to have been botched.  As things stand, these fields report times in
units of HZ, so that userland gets information that varies depending on
the HZ that the kernel was configured with.  This patch changes the
reported values to use USER_HZ units.
Signed-off-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fae5fa44 changed do_signal_stop() to check
SIGNAL_UNKILLABLE, this wasn't needed.  If signal_group_exit() == F, the
signal sent to SIGNAL_UNKILLABLE task must be already filtered out by the
caller, get_signal_to_deliver().  And if signal_group_exit() == T we are
not going to stop.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

dequeue_signal() checks SIGNAL_GROUP_EXIT before setting
SIGNAL_STOP_DEQUEUED.  This was added by
788e05a6 a long ago to avoid the
coredump/SIGSTOP race.

Since then the related code was changed, and now this subtle check is both
incomplete and unneeded at the same time.  It is incomplete because
nowadays exec() doesn't set SIGNAL_GROUP_EXIT, so in fact we should check
signal_group_exit() to avoid a similar race.  Fortunately, we doesn't need
the check at all.  The only function which relies on SIGNAL_STOP_DEQUEUED
is do_signal_stop(), and it ignores this flag if signal_group_exit() == T,
this covers the SIGNAL_GROUP_EXIT case.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no reason for rcu_read_lock() in __exit_signal().  tsk->sighand
can only be changed if tsk does exec, obviously this is not possible.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the recent changes collect_signal() always returns true.  Change it
to return void and update the single caller.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Factor out sigdelset() calls and remove the "still_pending" variable.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

collect_signal() checks sigismember(&list->signal, sig), this is not
needed.  This "sig" was just found by next_signal(), so it must be valid.

We have a (completely broken) call to ->notifier in between, but it must
not play with sigpending->signal bits or unlock ->siglock.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

release_posix_timer() can't be called with ->it_process != NULL.  Once
sys_timer_create() sets ->it_process it must not call
release_posix_timer(), otherwise we can race with another thread doing
sys_timer_delete(), this timer is visible to idr_find() and unlocked.

The same is true for two other callers (actually, for any possible
caller), sys_timer_delete() and itimer_delete().  They must clear
->it_process before unlock_timer() + release_posix_timer().
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NRoland McGrath <roland@redhat.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sys_timer_delete() and itimer_delete() check "timer->it_process != NULL",
this looks completely bogus.  ->it_process == NULL means that this timer
is already under destruction or it is not fully initialized, this must not
happen.

	sys_timer_delete: the timer is locked, and lock_timer() can't succeed
	if ->it_process == NULL.

	itimer_delete: it is called by exit_itimers() when there are no other
	threads which can play with signal_struct->posix_timers.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NRoland McGrath <roland@redhat.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>