The newly added global free list allows to avoid lengthy pool_list
iterations in free_obj_work() by putting objects either into the pool list
when the fill level of the pool is below the maximum or by putting them on
the global free list immediately.

As the pool is now guaranteed to never exceed the maximum fill level this
allows to remove the batch removal from pool list in free_obj_work().

Split free_object() into two parts, so the actual queueing function can be
reused without invoking schedule_work() on every invocation.

[ tglx: Remove the batch removal from pool list and massage changelog ]
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: longman@redhat.com
Link: https://lkml.kernel.org/r/1517872708-24207-4-git-send-email-yang.shi@linux.alibaba.com

free_object() adds objects to the pool list and schedules work when the
pool list is larger than the pool size.  The worker handles the actual
kfree() of the object by iterating the pool list until the pool size is
below the maximum pool size again.

To iterate the pool list, pool_lock has to be held and the objects which
should be freed() need to be put into temporary storage so pool_lock can be
dropped for the actual kmem_cache_free() invocation. That's a pointless and
expensive exercise if there is a large number of objects to free.

In such a case its better to evaulate the fill level of the pool in
free_objects() and queue the object to free either in the pool list or if
it's full on a separate global free list.

The worker can then do the following simpler operation:

  - Move objects back from the global free list to the pool list if the
    pool list is not longer full.

  - Remove the remaining objects in a single list move operation from the
    global free list and do the kmem_cache_free() operation lockless from
    the temporary list head.

In fill_pool() the global free list is checked as well to avoid real
allocations from the kmem cache.

Add the necessary list head and a counter for the number of objects on the
global free list and export that counter via sysfs:

max_chain     :79
max_loops     :8147
warnings      :0
fixups        :0
pool_free     :1697
pool_min_free :346
pool_used     :15356
pool_max_used :23933
on_free_list  :39
objs_allocated:32617
objs_freed    :16588

Nothing queues objects on the global free list yet. This happens in a
follow up change.

[ tglx: Simplified implementation and massaged changelog ]
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: longman@redhat.com
Link: https://lkml.kernel.org/r/1517872708-24207-3-git-send-email-yang.shi@linux.alibaba.com

__debug_check_no_obj_freed() can be an expensive operation depending on the
size of memory freed. It already exports the maximum chain walk length via
debugfs, but this only records the maximum of a single memory chunk.

Though there is no information about the total number of objects inspected
for a __debug_check_no_obj_freed() operation, which might be significantly
larger when a huge memory region is freed.

Aggregate the number of objects inspected for a single invocation of
__debug_check_no_obj_freed() and export it via sysfs.

The resulting output of /sys/kernel/debug/debug_objects/stats looks like:

max_chain     :121
max_checked   :543267
warnings      :0
fixups        :0
pool_free     :1764
pool_min_free :341
pool_used     :86438
pool_max_used :268887
objs_allocated:6068254
objs_freed    :5981076

[ tglx: Renamed the variable to max_checked and adjusted changelog ]
Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: longman@redhat.com
Link: https://lkml.kernel.org/r/1517872708-24207-2-git-send-email-yang.shi@linux.alibaba.com

The allocated debug objects are either on the free list or in the
hashed bucket lists. So they won't get lost. However if both debug
objects and kmemleak are enabled and kmemleak scanning is done
while some of the debug objects are transitioning from one list to
the others, false negative reporting of memory leaks may happen for
those objects. For example,

[38687.275678] kmemleak: 12 new suspected memory leaks (see
/sys/kernel/debug/kmemleak)
unreferenced object 0xffff92e98aabeb68 (size 40):
  comm "ksmtuned", pid 4344, jiffies 4298403600 (age 906.430s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 d0 bc db 92 e9 92 ff ff  ................
    01 00 00 00 00 00 00 00 38 36 8a 61 e9 92 ff ff  ........86.a....
  backtrace:
    [<ffffffff8fa5378a>] kmemleak_alloc+0x4a/0xa0
    [<ffffffff8f47c019>] kmem_cache_alloc+0xe9/0x320
    [<ffffffff8f62ed96>] __debug_object_init+0x3e6/0x400
    [<ffffffff8f62ef01>] debug_object_activate+0x131/0x210
    [<ffffffff8f330d9f>] __call_rcu+0x3f/0x400
    [<ffffffff8f33117d>] call_rcu_sched+0x1d/0x20
    [<ffffffff8f4a183c>] put_object+0x2c/0x40
    [<ffffffff8f4a188c>] __delete_object+0x3c/0x50
    [<ffffffff8f4a18bd>] delete_object_full+0x1d/0x20
    [<ffffffff8fa535c2>] kmemleak_free+0x32/0x80
    [<ffffffff8f47af07>] kmem_cache_free+0x77/0x350
    [<ffffffff8f453912>] unlink_anon_vmas+0x82/0x1e0
    [<ffffffff8f440341>] free_pgtables+0xa1/0x110
    [<ffffffff8f44af91>] exit_mmap+0xc1/0x170
    [<ffffffff8f29db60>] mmput+0x80/0x150
    [<ffffffff8f2a7609>] do_exit+0x2a9/0xd20

The references in the debug objects may also hide a real memory leak.

As there is no point in having kmemleak to track debug object
allocations, kmemleak checking is now disabled for debug objects.
Signed-off-by: NWaiman Long <longman@redhat.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1502718733-8527-1-git-send-email-longman@redhat.com

We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

As suggested by Ingo, the debug_objects_alloc counter is now renamed to
debug_objects_allocated with minor twist in comment and debug output.
Signed-off-by: NWaiman Long <longman@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1486503630-1501-1-git-send-email-longman@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

On a large SMP system with many CPUs, the global pool_lock may become
a performance bottleneck as all the CPUs that need to allocate or
free debug objects have to take the lock. That can sometimes cause
soft lockups like:

 NMI watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [rcuos/1:21]
 ...
 RIP: 0010:[<ffffffff817c216b>]  [<ffffffff817c216b>]
	_raw_spin_unlock_irqrestore+0x3b/0x60
 ...
 Call Trace:
  [<ffffffff813f40d1>] free_object+0x81/0xb0
  [<ffffffff813f4f33>] debug_check_no_obj_freed+0x193/0x220
  [<ffffffff81101a59>] ? trace_hardirqs_on_caller+0xf9/0x1c0
  [<ffffffff81284996>] ? file_free_rcu+0x36/0x60
  [<ffffffff81251712>] kmem_cache_free+0xd2/0x380
  [<ffffffff81284960>] ? fput+0x90/0x90
  [<ffffffff81284996>] file_free_rcu+0x36/0x60
  [<ffffffff81124c23>] rcu_nocb_kthread+0x1b3/0x550
  [<ffffffff81124b71>] ? rcu_nocb_kthread+0x101/0x550
  [<ffffffff81124a70>] ? sync_exp_work_done.constprop.63+0x50/0x50
  [<ffffffff810c59d1>] kthread+0x101/0x120
  [<ffffffff81101a59>] ? trace_hardirqs_on_caller+0xf9/0x1c0
  [<ffffffff817c2d32>] ret_from_fork+0x22/0x50

To reduce the amount of contention on the pool_lock, the actual
kmem_cache_free() of the debug objects will be delayed if the pool_lock
is busy. This will temporarily increase the amount of free objects
available at the free pool when the system is busy. As a result,
the number of kmem_cache allocation and freeing is reduced.

To further reduce the lock operations free debug objects in batches of
four.
Signed-off-by: NWaiman Long <longman@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Du Changbin" <changbin.du@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Stancek <jstancek@redhat.com>
Link: http://lkml.kernel.org/r/1483647425-4135-4-git-send-email-longman@redhat.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

On a large SMP systems with hundreds of CPUs, the current thresholds
for allocating and freeing debug objects (256 and 1024 respectively)
may not work well. This can cause a lot of needless calls to
kmem_aloc() and kmem_free() on those systems.

To alleviate this thrashing problem, the object freeing threshold
is now increased to "1024 + # of CPUs * 32". Whereas the object
allocation threshold is increased to "256 + # of CPUs * 4". That
should make the debug objects subsystem scale better with the number
of CPUs available in the system.
Signed-off-by: NWaiman Long <longman@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Du Changbin" <changbin.du@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Stancek <jstancek@redhat.com>
Link: http://lkml.kernel.org/r/1483647425-4135-3-git-send-email-longman@redhat.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

New debugfs stat counters are added to track the numbers of
kmem_cache_alloc() and kmem_cache_free() function calls to get a
sense of how the internal debug objects cache management is performing.
Signed-off-by: NWaiman Long <longman@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Du Changbin" <changbin.du@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Stancek <jstancek@redhat.com>
Link: http://lkml.kernel.org/r/1483647425-4135-2-git-send-email-longman@redhat.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Drivers, or other modules, that use a mixture of objects (especially
objects embedded within other objects) would like to take advantage of
the debugobjects facilities to help catch misuse.  Currently, the
debugobjects interface is only available to builtin drivers and requires
a set of EXPORT_SYMBOL_GPL for use by modules.

I am using the debugobjects in i915.ko to try and catch some invalid
operations on embedded objects.  The problem currently only presents
itself across module unload so forcing i915 to be builtin is not an
option.

Link: http://lkml.kernel.org/r/20161122143039.6433-1-chris@chris-wilson.co.ukSigned-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: "Du, Changbin" <changbin.du@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that workqueue can handle work item queueing from very early
during boot, there is no need to gate schedule_work() while
!keventd_up().  Remove it.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>

When activating a static object we need make sure that the object is
tracked in the object tracker.  If it is a non-static object then the
activation is illegal.

In previous implementation, each subsystem need take care of this in
their fixup callbacks.  Actually we can put it into debugobjects core.
Thus we can save duplicated code, and have *pure* fixup callbacks.

To achieve this, a new callback "is_static_object" is introduced to let
the type specific code decide whether a object is static or not.  If
yes, we take it into object tracker, otherwise give warning and invoke
fixup callback.

This change has paassed debugobjects selftest, and I also do some test
with all debugobjects supports enabled.

At last, I have a concern about the fixups that can it change the object
which is in incorrect state on fixup? Because the 'addr' may not point
to any valid object if a non-static object is not tracked.  Then Change
such object can overwrite someone's memory and cause unexpected
behaviour.  For example, the timer_fixup_activate bind timer to function
stub_timer.

Link: http://lkml.kernel.org/r/1462576157-14539-1-git-send-email-changbin.du@intel.com
[changbin.du@intel.com: improve code comments where invoke the new is_static_object callback]
  Link: http://lkml.kernel.org/r/1462777431-8171-1-git-send-email-changbin.du@intel.comSigned-off-by: NDu, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If debug_object_fixup() return non-zero when problem has been fixed.
But the code got it backwards, it taks 0 as fixup successfully.  So fix
it.
Signed-off-by: NDu, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I am going to introduce debugobjects infrastructure to USB subsystem.
But before this, I found the code of debugobjects could be improved.
This patchset will make fixup functions return bool type instead of int.
Because fixup only need report success or no.  boolean is the 'real'
type.

This patch (of 7):

The object debugging infrastructure core provides some fixup callbacks
for the subsystem who use it.  These callbacks are called from the debug
code whenever a problem in debug_object_init is detected.  And
debugobjects core suppose them returns 1 when the fixup was successful,
otherwise 0.  So the return type is boolean.

A bad thing is that debug_object_fixup use the return value for
arithmetic operation.  It confused me that what is the reall return
type.

Reading over the whole code, I found some place do use the return value
incorrectly(see next patch).  So why use bool type instead?
Signed-off-by: NDu, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On my bigger s390 systems  I always get "Out of memory.
ODEBUG disabled". Since the number of objects is needed at
compile time, we can not change the size dynamically before
the caches etc are available. Doubling the size seems to
do the trick. Since it is init data it will be freed anyway,
this should be ok.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Link: http://lkml.kernel.org/r/1453905478-13409-1-git-send-email-borntraeger@de.ibm.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Direct conversion of one KERN_DEBUG message without DEBUG definition
(suggested by Josh Triplett)

That message will now be disabled by default.  (see
Documentation/CodingStyle Chapter 13)
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add ODEBUG: prefix to pr_fmt
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert all printk to pr_foo() except KERN_DEBUG (see
Documentation/CodingStyle Chapter 13)
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove unnecessary work pending test before calling schedule_work().  It
has been tested in queue_work_on() already.  No functional changed.
Signed-off-by: NXie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In order to better respond to things like duplicate invocations
of call_rcu(), RCU needs to see the status of a call to
debug_object_activate().  This would allow RCU to leak the callback in
order to avoid adding freelist-reuse mischief to the duplicate invoations.
This commit therefore makes debug_object_activate() return status,
zero for success and -EINVAL for failure.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: NSedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

I'm not sure why, but the hlist for each entry iterators were conceived

        list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

        hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

 - Fix up the actual hlist iterators in linux/list.h
 - Fix up the declaration of other iterators based on the hlist ones.
 - A very small amount of places were using the 'node' parameter, this
 was modified to use 'obj->member' instead.
 - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
 properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
    <+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
    ...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There was a return missed in 1fda107d "debugobjects: Remove unused
return value from fill_pool()".  It makes gcc complain:

	lib/debugobjects.c: In function ‘fill_pool’:
	lib/debugobjects.c:98:4: warning: ‘return’ with a value, in
		function returning void [enabled by default]
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Link: http://lkml.kernel.org/r/20120418112810.GA2669@elgon.mountainSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

No point in keeping interrupts disabled here.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

debugobjects is now printing a warning when a fixup for a NOTAVAILABLE
object is run.  This causes the selftest to fail like:

	ODEBUG: selftest warnings failed 4 != 5

We could just increase the number of warnings that the selftest is
expecting to see because that is actually what has changed.  But, it turns
out that fixup_activate() was written with inverted logic and thus a fixup
for a static object returned 1 indicating the object had been fixed, and 0
otherwise.  Fix the logic to be correct and update the counts to reflect
that nothing needed fixing for a static object.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Reported-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Calling del_timer_sync() on an uninitialized timer leads to a
never ending loop in lock_timer_base() that spins checking for a
non-NULL timer base. Add an assertion to debugobjects to catch
usage of uninitialized objects so that we can initialize timers
in the del_timer_sync() path before it calls lock_timer_base().

[ sboyd@codeaurora.org: Clarify commit message ]
Signed-off-by: NChristine Chan <cschan@codeaurora.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1320724108-20788-3-git-send-email-sboyd@codeaurora.orgSigned-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Make debugobjects use the return code from the fixup function. That
allows us better diagnostics in the activate check than relying on a
WARN_ON() in the object specific code.

[ tglx@linutronix.de: Split out the debugobjects vs. the timer change ]
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Cc: Christine Chan <cschan@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1320724108-20788-2-git-send-email-sboyd@codeaurora.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Order of initialization look like this:
...
debugobjects
kmemleak
...(lots of other subsystems)...
workqueues (through early initcall)
...

debugobjects use schedule_work for batch freeing of its data and kmemleak
heavily use debugobjects, so when it comes to freeing and workqueues were
not initialized yet, kernel crashes:

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff810854d1>] __queue_work+0x29/0x41a
 [<ffffffff81085910>] queue_work_on+0x16/0x1d
 [<ffffffff81085abc>] queue_work+0x29/0x55
 [<ffffffff81085afb>] schedule_work+0x13/0x15
 [<ffffffff81242de1>] free_object+0x90/0x95
 [<ffffffff81242f6d>] debug_check_no_obj_freed+0x187/0x1d3
 [<ffffffff814b6504>] ? _raw_spin_unlock_irqrestore+0x30/0x4d
 [<ffffffff8110bd14>] ? free_object_rcu+0x68/0x6d
 [<ffffffff8110890c>] kmem_cache_free+0x64/0x12c
 [<ffffffff8110bd14>] free_object_rcu+0x68/0x6d
 [<ffffffff810b58bc>] __rcu_process_callbacks+0x1b6/0x2d9
...

because system_wq is NULL.

Fix it by checking if workqueues susbystem was initialized before using.
Signed-off-by: NMarcin Slusarz <marcin.slusarz@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/20110528112342.GA3068@joi.lanSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

In complex subsystems like mac80211 structures can contain several
timers and work structs, so identifying a specific instance from the
call trace and object type output of debugobjects can be hard.

Allow the subsystems which support debugobjects to provide a hint
function. This function returns a pointer to a kernel address
(preferrably the objects callback function) which is printed along
with the debugobjects type.

Add hint methods for timer_list, work_struct and hrtimer.

[ tglx: Massaged changelog, made it compile ]
Signed-off-by: NStanislaw Gruszka <sgruszka@redhat.com>
LKML-Reference: <20110307085809.GA9334@redhat.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Implement a basic state machine checker in the debugobjects.

This state machine checker detects races and inconsistencies within the "active"
life of a debugobject. The checker only keeps track of the current state; all
the state machine logic is kept at the object instance level.

The checker works by adding a supplementary "unsigned int astate" field to the
debug_obj structure. It keeps track of the current "active state" of the object.

The only constraints that are imposed on the states by the debugobjects system
is that:

- activation of an object sets the current active state to 0,
- deactivation of an object expects the current active state to be 0.

For the rest of the states, the state mapping is determined by the specific
object instance. Therefore, the logic keeping track of the state machine is
within the specialized instance, without any need to know about it at the
debugobject level.

The current object active state is changed by calling:

debug_object_active_state(addr, descr, expect, next)

where "expect" is the expected state and "next" is the next state to move to if
the expected state is found. A warning is generated if the expected is not
found.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid S. Miller <davem@davemloft.net>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: akpm@linux-foundation.org
CC: mingo@elte.hu
CC: laijs@cn.fujitsu.com
CC: dipankar@in.ibm.com
CC: josh@joshtriplett.org
CC: dvhltc@us.ibm.com
CC: niv@us.ibm.com
CC: peterz@infradead.org
CC: rostedt@goodmis.org
CC: Valdis.Kletnieks@vt.edu
CC: dhowells@redhat.com
CC: eric.dumazet@gmail.com
CC: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

This patch marks two functions, which only get called at
initialization, as __init.

Here is also interesting, that modpost doesn't catch here the right
function name.

WARNING: lib/built-in.o(.text+0x585f): Section mismatch in reference
from the function T.506() to the variable .init.data:obj
The function T.506() references the variable __initdata obj.
This is often because T.506 lacks a __initdata annotation or the 
annotation of obj is wrong.
Signed-off-by: NHenrik Kretzschmar <henne@nachtwindheim.de>
LKML-Reference: <1269632315-19403-1-git-send-email-henne@nachtwindheim.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NIngo Molnar <mingo@elte.hu>

After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>

Impact: avoid recursive kfree calls, less slab activity on heavy load

debugobjects checks on kfree whether tracked objects are freed. When a
tracked object is freed debugobjects frees the internal reference
object as well. The debug object slab cache is marked to not recurse
into debugobjects when a slab objects is freed, but the recursive call
can be problematic versus locking in the memory allocator.

Defer the freeing of debug slab objects via schedule_work. The reasons
not to use RCU are:

1) rcu makes the data structure larger
2) there is no real need for rcu as nothing references the obj after
   we freed it
3) under heavy load it is easier to reuse the to be freed objects instead
   of allocating new objects from the slab. This lowered the slab activity
   significantly in a heavy load networking test where lots of timers are
   created/destroyed. The workqueue based delayed free allows us just to
   put the to be freed objects back into the object pool and reuse them
   right away.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
LKML-Reference: <200903162049.58058.nickpiggin@yahoo.com.au>

Impact: refactor/consolidate object management, prepare for delayed free

debugobjects allocates static reference objects to track objects which
are initialized or activated before the slab cache becomes
available. These static reference objects have to be handled
seperately in free_object(). The handling of these objects is in the
way of implementing a delayed free functionality. The delayed free is
required to avoid callbacks into the mm code from
debug_check_no_obj_freed().

Replace the static object references with dynamic ones after the slab
cache has been initialized. The static objects are now marked initdata.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
LKML-Reference: <200903162049.58058.nickpiggin@yahoo.com.au>

While trying to debug why my Atom netbook is falling over booting
rawhide debug-enabled kernels, I stumbled across the fact that we've
been enabling object debugging by default. However, once you default it
to on, you've got no way to turn it back off again at runtime.

Add a boolean toggle to turn it off. I would just make it an int
module_param, however people may already expect the boolean enable
behaviour, so just add an analogue for disabling.
Signed-off-by: NKyle McMartin <kyle@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: add .config driven boot parameter default value

Right now debugobjects can only be activated if the debug_objects
boot parameter is passed in via the boot command line.

Make this more convenient (and randomizable) by also providing
a .config method. Enable it by default. (DEBUG_OBJECTS itself
is default-off)
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Daniel J. Blueman reported:
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.27-rc4-224c #1
> -------------------------------------------------------
> hald/4680 is trying to acquire lock:
>  (&n->list_lock){++..}, at: [<ffffffff802bfa26>] add_partial+0x26/0x80
>
> but task is already holding lock:
>  (&obj_hash[i].lock){++..}, at: [<ffffffff8041cfdc>]
> debug_object_free+0x5c/0x120

We fix it by moving the actual freeing to outside the lock (the lock
now only protects the list).

The pool lock is also promoted to irq-safe (suggested by Dan). It's
necessary because free_pool is now called outside the irq disabled
region. So we need to protect against an interrupt handler which calls
debug_object_init().

[tglx@linutronix.de: added hlist_move_list helper to avoid looping
		     through the list twice]
Reported-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Use WARN() instead of a printk+WARN_ON() pair; this way the message becomes
part of the warning section for better reporting/collection.  In addition, one
of the if() clauses collapes into the WARN() entirely now.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>