Commit Graph

216 Commits

Author SHA1 Message Date
Ingo Molnar 8302294f43 Merge branch 'tracing/core-v2' into tracing-for-linus
Conflicts:
	include/linux/slub_def.h
	lib/Kconfig.debug
	mm/slob.c
	mm/slub.c
2009-04-02 00:49:02 +02:00
Peter Zijlstra eedeeabdee lockdep: add stack dumps to asserts
Have a better idea about exactly which loc causes a lockdep
limit overflow. Often it's a bug or inefficiency in that
subsystem.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1237376327.5069.253.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-31 14:53:01 +02:00
Ingo Molnar 7bee946358 Merge branch 'linus' into locking-for-linus
Conflicts:
	lib/Kconfig.debug
2009-03-31 13:53:43 +02:00
Peter Zijlstra 2f85018152 lockdep: fix deadlock in lockdep_trace_alloc
Heiko reported that we grab the graph lock with irqs enabled.

Fix this by providng the same wrapper as all other lockdep entry
functions have.

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <npiggin@suse.de>
LKML-Reference: <1237544000.24626.52.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-30 23:19:24 +02:00
Ingo Molnar 480c93df5b Merge branch 'core/locking' into tracing/ftrace 2009-03-13 01:33:21 +01:00
David Rientjes 03d78913f0 lockdep: remove duplicate CONFIG_DEBUG_LOCKDEP definitions
Impact: cleanup

The atomic debug modifiers are already defined in
kernel/lockdep_internals.h.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <alpine.DEB.2.00.0903050222160.30401@chino.kir.corp.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-05 11:46:00 +01:00
Peter Zijlstra efed792d67 tracing: add lockdep tracepoints for lock acquire/release
Augment the traces with lock names when lockdep is available:

 1)               |  down_read_trylock() {
 1)               |    _spin_lock_irqsave() {
 1)               |      /* lock_acquire: &sem->wait_lock */
 1)   4.201 us    |    }
 1)               |    _spin_unlock_irqrestore() {
 1)               |      /* lock_release: &sem->wait_lock */
 1)   3.523 us    |    }
 1)               |  /* lock_acquire: try read &mm->mmap_sem */
 1) + 13.386 us   |  }
 1)   1.635 us    |  find_vma();
 1)               |  handle_mm_fault() {
 1)               |    __do_fault() {
 1)               |      filemap_fault() {
 1)               |        find_lock_page() {
 1)               |          find_get_page() {
 1)               |            /* lock_acquire: read rcu_read_lock */
 1)               |            /* lock_release: rcu_read_lock */
 1)   5.697 us    |          }
 1)   8.158 us    |        }
 1) + 11.079 us   |      }
 1)               |      _spin_lock() {
 1)               |        /* lock_acquire: __pte_lockptr(page) */
 1)   3.949 us    |      }
 1)   1.460 us    |      page_add_file_rmap();
 1)               |      _spin_unlock() {
 1)               |        /* lock_release: __pte_lockptr(page) */
 1)   3.115 us    |      }
 1)               |      unlock_page() {
 1)   1.421 us    |        page_waitqueue();
 1)   1.220 us    |        __wake_up_bit();
 1)   6.519 us    |      }
 1) + 34.328 us   |    }
 1) + 37.452 us   |  }
 1)               |  up_read() {
 1)               |  /* lock_release: &mm->mmap_sem */
 1)               |    _spin_lock_irqsave() {
 1)               |      /* lock_acquire: &sem->wait_lock */
 1)   3.865 us    |    }
 1)               |    _spin_unlock_irqrestore() {
 1)               |      /* lock_release: &sem->wait_lock */
 1)   8.562 us    |    }
 1) + 17.370 us   |  }

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?T=F6r=F6k?= Edwin <edwintorok@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1236166375.5330.7209.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-04 18:49:58 +01:00
Peter Zijlstra 26575e28df lockdep: remove extra "irq" string
Impact: clarify lockdep printk text

print_irq_inversion_bug() gets handed state strings of the form

  "HARDIRQ", "SOFTIRQ", "RECLAIM_FS"

and appends "-irq-{un,}safe" to them, which is either redudant for *IRQ or
confusing in the RECLAIM_FS case.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1236175192.5330.7585.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-04 18:38:34 +01:00
Peter Zijlstra 1c21f14ec4 lockdep: fix incorrect state name
In the recent mark_lock_irq() rework a bug snuck in that would report the
state of write locks causing irq inversion under a read lock as a read
lock.

Fix this by masking the read bit of the state when validating write
dependencies.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1236172646.5330.7450.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-04 18:38:33 +01:00
Peter Zijlstra 868a23a804 lockdep: build fix for !PROVE_LOCKING
The __GFP_FS annotations fail to build with CONFIG_LOCKDEP=y,
CONFIG_PROVE_LOCKING=n, ammend that.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-15 00:30:26 +01:00
Peter Zijlstra b4b136f44b lockdep: use stringify.h
Arnd pointed out we have the stringify macro magic already in-kernel.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:26 +01:00
Peter Zijlstra 4f367d8adc lockdep: simplify check_prev_add_irq()
Remove the manual state iteration thingy.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:24 +01:00
Peter Zijlstra f510b233cf lockdep: get_user_chars() redo
Generic, states independent, get_user_chars().

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:22 +01:00
Peter Zijlstra 3ff176ca47 lockdep: simplify get_user_chars()
there's too much repetition of code..

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:21 +01:00
Peter Zijlstra 38aa271438 lockdep: add comments to mark_lock_irq()
re-add some of the comments that got lost in the refactoring.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:19 +01:00
Peter Zijlstra cf2ad4d13c lockdep: remove macro usage from mark_held_locks()
Now that we have nice numerical relations for the states, remove the macro
magics.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:17 +01:00
Peter Zijlstra 9d3651a23d lockdep: fully reduce mark_lock_irq()
Now what its only two functions, they again look rather similar.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:15 +01:00
Peter Zijlstra 42c50d544e lockdep: merge the !_READ mark_lock_irq() helpers
These two are also remakably similar

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:13 +01:00
Peter Zijlstra 780e820b2d lockdep: merge the _READ mark_lock_irq() helpers
The _READ helpers show remarkable similarity, merge them.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:12 +01:00
Peter Zijlstra cd95302d25 lockdep: simplify mark_lock_irq() helpers #3
Kill another argument

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:10 +01:00
Peter Zijlstra f989209e2f lockdep: further simplify mark_lock_irq() helpers
take away another parameter

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:08 +01:00
Peter Zijlstra 604de3b5b6 lockdep: simplify the mark_lock_irq() helpers
In order to unify them, take some arguments away

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:06 +01:00
Peter Zijlstra 6a6904d347 lockdep: split up mark_lock_irq()
split mark_lock_irq() into 4 simple helper functions

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:04 +01:00
Peter Zijlstra fabe9c42c6 lockdep: generate usage strings
generate the usage strings

XXX capital invasion :-(

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:02 +01:00
Peter Zijlstra 5346417e17 lockdep: simplify mark_lock()
remove the state iteration

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:57 +01:00
Peter Zijlstra 36bfb9bb03 lockdep: simplify mark_held_locks
remove the explicit state iteration

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:56 +01:00
Peter Zijlstra a652d7081b lockdep: sanitize reclaim bit names
s/HELD_OVER/ENABLED/g

so that its similar to the hard and soft-irq names.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:52 +01:00
Peter Zijlstra 4fc95e867f lockdep: sanitize bit names
s/\(LOCKF\?_ENABLED_[^ ]*\)S\(_READ\)\?\>/\1\2/g

So that the USED_IN and ENABLED have the same names.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:51 +01:00
Nick Piggin cf40bd16fd lockdep: annotate reclaim context (__GFP_NOFS)
Here is another version, with the incremental patch rolled up, and
added reclaim context annotation to kswapd, and allocation tracing
to slab allocators (which may only ever reach the page allocator
in rare cases, so it is good to put annotations here too).

Haven't tested this version as such, but it should be getting closer
to merge worthy ;)

--
After noticing some code in mm/filemap.c accidentally perform a __GFP_FS
allocation when it should not have been, I thought it might be a good idea to
try to catch this kind of thing with lockdep.

I coded up a little idea that seems to work. Unfortunately the system has to
actually be in __GFP_FS page reclaim, then take the lock, before it will mark
it. But at least that might still be some orders of magnitude more common
(and more debuggable) than an actual deadlock condition, so we have some
improvement I hope (the concept is no less complete than discovery of a lock's
interrupt contexts).

I guess we could even do the same thing with __GFP_IO (normal reclaim), and
even GFP_NOIO locks too... but filesystems will have the most locks and fiddly
code paths, so let's start there and see how it goes.

It *seems* to work. I did a quick test.

=================================
[ INFO: inconsistent lock state ]
2.6.28-rc6-00007-ged31348-dirty #26
---------------------------------
inconsistent {in-reclaim-W} -> {ov-reclaim-W} usage.
modprobe/8526 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]
{in-reclaim-W} state was registered at:
  [<ffffffff80267bdb>] __lock_acquire+0x75b/0x1a60
  [<ffffffff80268f71>] lock_acquire+0x91/0xc0
  [<ffffffff8070f0e1>] mutex_lock_nested+0xb1/0x310
  [<ffffffffa002002b>] brd_init+0x2b/0x216 [brd]
  [<ffffffff8020903b>] _stext+0x3b/0x170
  [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
  [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 3929
hardirqs last  enabled at (3929): [<ffffffff8070f2b5>] mutex_lock_nested+0x285/0x310
hardirqs last disabled at (3928): [<ffffffff8070f089>] mutex_lock_nested+0x59/0x310
softirqs last  enabled at (3732): [<ffffffff8061f623>] sk_filter+0x83/0xe0
softirqs last disabled at (3730): [<ffffffff8061f5b6>] sk_filter+0x16/0xe0

other info that might help us debug this:
1 lock held by modprobe/8526:
 #0:  (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]

stack backtrace:
Pid: 8526, comm: modprobe Not tainted 2.6.28-rc6-00007-ged31348-dirty #26
Call Trace:
 [<ffffffff80265483>] print_usage_bug+0x193/0x1d0
 [<ffffffff80266530>] mark_lock+0xaf0/0xca0
 [<ffffffff80266735>] mark_held_locks+0x55/0xc0
 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
 [<ffffffff802667ca>] trace_reclaim_fs+0x2a/0x60
 [<ffffffff80285005>] __alloc_pages_internal+0x475/0x580
 [<ffffffff8070f29e>] ? mutex_lock_nested+0x26e/0x310
 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
 [<ffffffffa002006a>] brd_init+0x6a/0x216 [brd]
 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
 [<ffffffff8020903b>] _stext+0x3b/0x170
 [<ffffffff8070f8b9>] ? mutex_unlock+0x9/0x10
 [<ffffffff8070f83d>] ? __mutex_unlock_slowpath+0x10d/0x180
 [<ffffffff802669ec>] ? trace_hardirqs_on_caller+0x12c/0x190
 [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
 [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:49 +01:00
Linus Torvalds 5f34fe1cfc Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
  stacktrace: provide save_stack_trace_tsk() weak alias
  rcu: provide RCU options on non-preempt architectures too
  printk: fix discarding message when recursion_bug
  futex: clean up futex_(un)lock_pi fault handling
  "Tree RCU": scalable classic RCU implementation
  futex: rename field in futex_q to clarify single waiter semantics
  x86/swiotlb: add default swiotlb_arch_range_needs_mapping
  x86/swiotlb: add default phys<->bus conversion
  x86: unify pci iommu setup and allow swiotlb to compile for 32 bit
  x86: add swiotlb allocation functions
  swiotlb: consolidate swiotlb info message printing
  swiotlb: support bouncing of HighMem pages
  swiotlb: factor out copy to/from device
  swiotlb: add arch hook to force mapping
  swiotlb: allow architectures to override phys<->bus<->phys conversions
  swiotlb: add comment where we handle the overflow of a dma mask on 32 bit
  rcu: fix rcutorture behavior during reboot
  resources: skip sanity check of busy resources
  swiotlb: move some definitions to header
  swiotlb: allow architectures to override swiotlb pool allocation
  ...

Fix up trivial conflicts in
  arch/x86/kernel/Makefile
  arch/x86/mm/init_32.c
  include/linux/hardirq.h
as per Ingo's suggestions.
2008-12-30 16:10:19 -08:00
Peter Zijlstra 00ef9f7348 lockdep: change a held lock's class
Impact: introduce new lockdep API

Allow to change a held lock's class. Basically the same as the existing
code to change a subclass therefore reuse all that.

The XFS code will be able to use this to annotate their inode locking.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04 10:08:18 +01:00
Ingo Molnar cb9c34e6d0 Merge commit 'v2.6.28-rc7' into core/locking 2008-12-04 08:52:14 +01:00
Steven Rostedt a5e25883a4 ftrace: replace raw_local_irq_save with local_irq_save
Impact: fix for lockdep and ftrace

The raw_local_irq_save/restore confuses lockdep. This patch
converts them to the local_irq_save/restore variants.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03 08:56:19 +01:00
Ingo Molnar 7807fafa52 lockdep: fix unused function warning in kernel/lockdep.c
Impact: fix build warning

this warning:

  kernel/lockdep.c:584: warning: ‘print_lock_dependencies’ defined but not used

triggers because print_lock_dependencies() is only used if both
CONFIG_TRACE_IRQFLAGS and CONFIG_PROVE_LOCKING are enabled.

But adding #ifdefs is not an option here - it would spread out to 4-5
other helper functions and uglify the file. So mark this function
as __used - it's static and the compiler can eliminate it just fine.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-25 09:07:03 +01:00
Li Zefan b0788caf7a lockdep: consistent alignement for lockdep info
Impact: prettify /proc/lockdep_info

Just feel odd that not all lines of lockdep info are aligned.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-21 08:59:40 +01:00
Ingo Molnar 708b8eae0f Merge branch 'linus' into core/locking 2008-11-12 12:39:21 +01:00
Heiko Carstens 6afe40b4da lockdep: fix irqs on/off ip tracing
Impact: fix lockdep lock-api-caller output when irqsoff tracing is enabled

81d68a96 "ftrace: trace irq disabled critical timings" added wrappers around
trace_hardirqs_on/off_caller. However these functions use
__builtin_return_address(0) to figure out which function actually disabled
or enabled irqs. The result is that we save the ips of trace_hardirqs_on/off
instead of the real caller. Not very helpful.

However since the patch from Steven the ip already gets passed. So use that
and get rid of __builtin_return_address(0) in these two functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-28 11:19:07 +01:00
qinghuang feng 46fec7ac40 lockdep: minor fix for debug_show_all_locks()
When we failed to get tasklist_lock eventually (count equals 0),
we should only print " ignoring it.\n", and not print
" locked it.\n" needlessly.

Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-28 10:30:04 +01:00
Peter Zijlstra c7e78cff6b lockstat: contend with points
We currently only provide points that have to wait on contention, also
lists the points we have to wait for.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-20 15:43:10 +02:00
Zhu Yi 7487017282 lockdep: fix invalid list_del_rcu in zap_class
The problem is found during iwlagn driver testing on
v2.6.27-rc4-176-gb8e6c91 kernel, but it turns out to be a lockdep bug.
In our testing, we frequently load and unload the iwlagn driver
(>50 times). Then the MAX_STACK_TRACE_ENTRIES is reached (expected
behaviour?). The error message with the call trace is as below.

BUG: MAX_STACK_TRACE_ENTRIES too low!
turning off the locking correctness validator.
Pid: 4895, comm: iwlagn Not tainted 2.6.27-rc4 #13

Call Trace:
 [<ffffffff81014aa1>] save_stack_trace+0x22/0x3e
 [<ffffffff8105390a>] save_trace+0x8b/0x91
 [<ffffffff81054e60>] mark_lock+0x1b0/0x8fa
 [<ffffffff81056f71>] __lock_acquire+0x5b9/0x716
 [<ffffffffa00d818a>] ieee80211_sta_work+0x0/0x6ea [mac80211]
 [<ffffffff81057120>] lock_acquire+0x52/0x6b
 [<ffffffff81045f0e>] run_workqueue+0x97/0x1ed
 [<ffffffff81045f5e>] run_workqueue+0xe7/0x1ed
 [<ffffffff81045f0e>] run_workqueue+0x97/0x1ed
 [<ffffffff81046ae4>] worker_thread+0xd8/0xe3
 [<ffffffff81049503>] autoremove_wake_function+0x0/0x2e
 [<ffffffff81046a0c>] worker_thread+0x0/0xe3
 [<ffffffff810493ec>] kthread+0x47/0x73
 [<ffffffff8128e3ab>] trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff8100cea9>] child_rip+0xa/0x11
 [<ffffffff8100c4df>] restore_args+0x0/0x30
 [<ffffffff810316e1>] finish_task_switch+0x0/0xcc
 [<ffffffff810493a5>] kthread+0x0/0x73
 [<ffffffff8100ce9f>] child_rip+0x0/0x11

Although the above is harmless, when the ilwagn module is removed
later lockdep will trigger a kernel oops as below.

BUG: unable to handle kernel NULL pointer dereference at
0000000000000008
IP: [<ffffffff810531e1>] zap_class+0x24/0x82
PGD 73128067 PUD 7448c067 PMD 0
Oops: 0002 [1] SMP
CPU 0
Modules linked in: rfcomm l2cap bluetooth autofs4 sunrpc
nf_conntrack_ipv6 xt_state nf_conntrack xt_tcpudp ip6t_ipv6header
ip6t_REJECT ip6table_filter ip6_tables x_tables ipv6 cpufreq_ondemand
acpi_cpufreq dm_mirror dm_log dm_multipath dm_mod snd_hda_intel sr_mod
snd_seq_dummy snd_seq_oss snd_seq_midi_event battery snd_seq
snd_seq_device cdrom button snd_pcm_oss snd_mixer_oss snd_pcm
snd_timer snd_page_alloc e1000e snd_hwdep sg iTCO_wdt
iTCO_vendor_support ac pcspkr i2c_i801 i2c_core snd soundcore video
output ata_piix ata_generic libata sd_mod scsi_mod ext3 jbd mbcache
uhci_hcd ohci_hcd ehci_hcd [last unloaded: mac80211]
Pid: 4941, comm: modprobe Not tainted 2.6.27-rc4 #10
RIP: 0010:[<ffffffff810531e1>]  [<ffffffff810531e1>]
zap_class+0x24/0x82
RSP: 0000:ffff88007bcb3eb0  EFLAGS: 00010046
RAX: 0000000000068ee8 RBX: ffffffff8192a0a0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000001dfb RDI: ffffffff816e70b0
RBP: ffffffffa00cd000 R08: ffffffff816818f8 R09: ffff88007c923558
R10: ffffe20002ad2408 R11: ffffffff811028ec R12: ffffffff8192a0a0
R13: 000000000002bd90 R14: 0000000000000000 R15: 0000000000000296
FS:  00007f9d1cee56f0(0000) GS:ffffffff814a58c0(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000008 CR3: 0000000073047000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process modprobe (pid: 4941, threadinfo ffff88007bcb2000, task
ffff8800758d1fc0)
Stack:  ffffffff81057376 0000000000000000 ffffffffa00f7b00
0000000000000000
 0000000000000080 0000000000618278 00007fff24f16720 0000000000000000
 ffffffff8105d37a ffffffffa00f7b00 ffffffff8105d591 313132303863616d
Call Trace:
 [<ffffffff81057376>] ? lockdep_free_key_range+0x61/0xf5
 [<ffffffff8105d37a>] ? free_module+0xd4/0xe4
 [<ffffffff8105d591>] ? sys_delete_module+0x1de/0x1f9
 [<ffffffff8106dbfa>] ? audit_syscall_entry+0x12d/0x160
 [<ffffffff8100be2b>] ? system_call_fastpath+0x16/0x1b

Code: b2 00 01 00 00 00 c3 31 f6 49 c7 c0 10 8a 61 81 eb 32 49 39 38
75 26 48 98 48 6b c0 38 48 8b 90 08 8a 61 81 48 8b 88 00 8a 61 81 <48>
89 51 08 48 89 0a 48 c7 80 08 8a 61 81 00 02 20 00 48 ff c6
RIP  [<ffffffff810531e1>] zap_class+0x24/0x82
 RSP <ffff88007bcb3eb0>
CR2: 0000000000000008
---[ end trace a1297e0c4abb0f2e ]---

The root cause for this oops is in add_lock_to_list() when
save_trace() fails due to MAX_STACK_TRACE_ENTRIES is reached,
entry->class is assigned but entry is never added into any lock list.
This makes the list_del_rcu() in zap_class() oops later when the
module is unloaded. This patch fixes the problem by assigning
entry->class after save_trace() returns success.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-27 08:40:36 +02:00
Joe Korty 04148b73b8 lockstat: repair erronous contention statistics
Fix bad contention counting in /proc/lock_stat.

/proc/lockstat tries to gather per-ip contention
statistics per-lock.  This was failing due to
a garbage per-ip index selector being used.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-26 10:37:47 +02:00
Dmitry Baryshkov 6951b12a0f lockdep: fix spurious 'inconsistent lock state' warning
Since f82b217e35 lockdep can output spurious
warnings related to hwirqs due to hardirq_off shrinkage from int to bit-sized
flag. Guard it with double negation to fix the warning.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-18 09:42:31 +02:00
Arjan van de Ven 2df8b1d656 lockdep: use WARN() in kernel/lockdep.c
Use WARN() instead of a printk+WARN_ON() pair; this way the message
becomes part of the warning section for better reporting/collection.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2008-08-13 19:06:46 +02:00
Peter Zijlstra 0f2bc27be2 lockdep: fix debug_lock_alloc
When we enable DEBUG_LOCK_ALLOC but do not enable PROVE_LOCKING and or
LOCK_STAT, lock_alloc() and lock_release() turn into nops, even though
we should be doing hlock checking (check=1).

This causes a false warning and a lockdep self-disable.

Rectify this.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 22:45:51 +02:00
Rabin Vincent 8bfe0298f7 lockdep: handle chains involving classes defined in modules
Solve this by marking the classes as unused and not printing information
about the unused classes.

Reported-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 09:30:26 +02:00
Peter Zijlstra 7531e2f34d lockdep: lock protection locks
On Fri, 2008-08-01 at 16:26 -0700, Linus Torvalds wrote:

> On Fri, 1 Aug 2008, David Miller wrote:
> >
> > Taking more than a few locks of the same class at once is bad
> > news and it's better to find an alternative method.
>
> It's not always wrong.
>
> If you can guarantee that anybody that takes more than one lock of a
> particular class will always take a single top-level lock _first_, then
> that's all good. You can obviously screw up and take the same lock _twice_
> (which will deadlock), but at least you cannot get into ABBA situations.
>
> So maybe the right thing to do is to just teach lockdep about "lock
> protection locks". That would have solved the multi-queue issues for
> networking too - all the actual network drivers would still have taken
> just their single queue lock, but the one case that needs to take all of
> them would have taken a separate top-level lock first.
>
> Never mind that the multi-queue locks were always taken in the same order:
> it's never wrong to just have some top-level serialization, and anybody
> who needs to take <n> locks might as well do <n+1>, because they sure as
> hell aren't going to be on _any_ fastpaths.
>
> So the simplest solution really sounds like just teaching lockdep about
> that one special case. It's not "nesting" exactly, although it's obviously
> related to it.

Do as Linus suggested. The lock protection lock is called nest_lock.

Note that we still have the MAX_LOCK_DEPTH (48) limit to consider, so anything
that spills that it still up shit creek.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 09:30:24 +02:00
Dave Jones f82b217e35 lockdep: shrink held_lock structure
struct held_lock {
        u64                        prev_chain_key;       /*     0     8 */
        struct lock_class *        class;                /*     8     8 */
        long unsigned int          acquire_ip;           /*    16     8 */
        struct lockdep_map *       instance;             /*    24     8 */
        int                        irq_context;          /*    32     4 */
        int                        trylock;              /*    36     4 */
        int                        read;                 /*    40     4 */
        int                        check;                /*    44     4 */
        int                        hardirqs_off;         /*    48     4 */

        /* size: 56, cachelines: 1 */
        /* padding: 4 */
        /* last cacheline: 56 bytes */
};

struct held_lock {
        u64                        prev_chain_key;       /*     0     8 */
        long unsigned int          acquire_ip;           /*     8     8 */
        struct lockdep_map *       instance;             /*    16     8 */
        unsigned int               class_idx:11;         /*    24:21  4 */
        unsigned int               irq_context:2;        /*    24:19  4 */
        unsigned int               trylock:1;            /*    24:18  4 */
        unsigned int               read:2;               /*    24:16  4 */
        unsigned int               check:2;              /*    24:14  4 */
        unsigned int               hardirqs_off:1;       /*    24:13  4 */

        /* size: 32, cachelines: 1 */
        /* padding: 4 */
        /* bit_padding: 13 bits */
        /* last cacheline: 32 bytes */
};

[mingo@elte.hu: shrunk hlock->class too]
[peterz@infradead.org: fixup bit sizes]
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2008-08-11 09:30:23 +02:00
Peter Zijlstra 64aa348edc lockdep: lock_set_subclass - reset a held lock's subclass
this can be used to reset a held lock's subclass, for arbitrary-depth
iterated data structures such as trees or lists which have per-node
locks.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 09:30:21 +02:00
David Miller 419ca3f135 lockdep: fix combinatorial explosion in lock subgraph traversal
When we traverse the graph, either forwards or backwards, we
are interested in whether a certain property exists somewhere
in a node reachable in the graph.

Therefore it is never necessary to traverse through a node more
than once to get a correct answer to the given query.

Take advantage of this property using a global ID counter so that we
need not clear all the markers in all the lock_class entries before
doing a traversal.  A new ID is choosen when we start to traverse, and
we continue through a lock_class only if it's ID hasn't been marked
with the new value yet.

This short-circuiting is essential especially for high CPU count
systems.  The scheduler has a runqueue per cpu, and needs to take
two runqueue locks at a time, which leads to long chains of
backwards and forwards subgraphs from these runqueue lock nodes.
Without the short-circuit implemented here, a graph traversal on
a runqueue lock can take up to (1 << (N - 1)) checks on a system
with N cpus.

For anything more than 16 cpus or so, lockdep will eventually bring
the machine to a complete standstill.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-31 18:38:28 +02:00
Linus Torvalds 40e7babbb5 Merge branch 'core/locking' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core/locking' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  lockdep: fix kernel/fork.c warning
  lockdep: fix ftrace irq tracing false positive
  lockdep: remove duplicate definition of STATIC_LOCKDEP_MAP_INIT
  lockdep: add lock_class information to lock_chain and output it
  lockdep: add lock_class information to lock_chain and output it
  lockdep: output lock_class key instead of address for forward dependency output
  __mutex_lock_common: use signal_pending_state()
  mutex-debug: check mutex magic before owner

Fixed up conflict in kernel/fork.c manually
2008-07-14 14:55:13 -07:00
Ingo Molnar 992860e991 lockdep: fix ftrace irq tracing false positive
fix this false positive:

[    0.020000] ------------[ cut here ]------------
[    0.020000] WARNING: at kernel/lockdep.c:2718 check_flags+0x14a/0x170()
[    0.020000] Modules linked in:
[    0.020000] Pid: 0, comm: swapper Not tainted 2.6.26-tip-00343-gd7e5521-dirty #14486
[    0.020000]  [<c01312e4>] warn_on_slowpath+0x54/0x80
[    0.020000]  [<c067e451>] ? _spin_unlock_irqrestore+0x61/0x70
[    0.020000]  [<c0131bb1>] ? release_console_sem+0x201/0x210
[    0.020000]  [<c0143d65>] ? __kernel_text_address+0x35/0x40
[    0.020000]  [<c010562e>] ? dump_trace+0x5e/0x140
[    0.020000]  [<c01518b5>] ? __lock_acquire+0x245/0x820
[    0.020000]  [<c015063a>] check_flags+0x14a/0x170
[    0.020000]  [<c0151ed8>] ? lock_acquire+0x48/0xc0
[    0.020000]  [<c0151ee1>] lock_acquire+0x51/0xc0
[    0.020000]  [<c014a16c>] ? down+0x2c/0x40
[    0.020000]  [<c010a609>] ? sched_clock+0x9/0x10
[    0.020000]  [<c067e7b2>] _write_lock+0x32/0x60
[    0.020000]  [<c013797f>] ? request_resource+0x1f/0xb0
[    0.020000]  [<c013797f>] request_resource+0x1f/0xb0
[    0.020000]  [<c02f89ad>] vgacon_startup+0x2bd/0x3e0
[    0.020000]  [<c094d62a>] con_init+0x19/0x22f
[    0.020000]  [<c0330c7c>] ? tty_register_ldisc+0x5c/0x70
[    0.020000]  [<c094cf49>] console_init+0x20/0x2e
[    0.020000]  [<c092a969>] start_kernel+0x20c/0x379
[    0.020000]  [<c092a516>] ? unknown_bootoption+0x0/0x1f6
[    0.020000]  [<c092a099>] __init_begin+0x99/0xa1
[    0.020000]  =======================
[    0.020000] ---[ end trace 4eaa2a86a8e2da22 ]---
[    0.020000] possible reason: unannotated irqs-on.
[    0.020000] irq event stamp: 0

which occurs if CONFIG_TRACE_IRQFLAGS=y, CONFIG_DEBUG_LOCKDEP=y,
but CONFIG_PROVE_LOCKING is disabled.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-14 10:32:14 +02:00
Huang, Ying cd1a28e845 lockdep: add lock_class information to lock_chain and output it
It is based on x86/master branch of git-x86 tree, and has been tested
on x86_64 platform.

ChangeLog:

v2:

- Enclosing proc file system related code into CONFIG_PROVE_LOCKING.

- Fix nr_chain_hlocks update code.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24 01:28:20 +02:00
Huang, Ying 443cd507ce lockdep: add lock_class information to lock_chain and output it
This patch records array of lock_class into lock_chain, and export
lock_chain information via /proc/lockdep_chains.

It is based on x86/master branch of git-x86 tree, and has been tested
on x86_64 platform.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-20 12:21:33 +02:00
Steven Rostedt bb065afb8e lockdep: update lockdep_recursion on graph_lock
With the introduction of ftrace, it is possible to recurse into
the lockdep functions via the mcount call. To prevent possible
lockups, updating the lockdep_recursion counter on grabbing the internal
lockdep_lock should prevent deadlocks.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 21:50:21 +02:00
Steven Rostedt 1d09daa55d ftrace: use Makefile to remove tracing from lockdep
This patch removes the "notrace" annotation from lockdep and adds the debugging
files in the kernel director to those that should not be compiled with
"-pg" mcount tracing.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 21:15:14 +02:00
Steven Rostedt 0764d23cf0 ftrace: lockdep notrace annotations
Add notrace annotations to lockdep to keep ftrace from causing
recursive problems with lock tracing and debugging.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:39:40 +02:00
Steven Rostedt 81d68a96a3 ftrace: trace irq disabled critical timings
This patch adds latency tracing for critical timings
(how long interrupts are disabled for).

 "irqsoff" is added to /debugfs/tracing/available_tracers

Note:
  tracing_max_latency
    also holds the max latency for irqsoff (in usecs).
   (default to large number so one must start latency tracing)

  tracing_thresh
    threshold (in usecs) to always print out if irqs off
    is detected to be longer than stated here.
    If irq_thresh is non-zero, then max_irq_latency
    is ignored.

Here's an example of a trace with ftrace_enabled = 0

=======
preemption latency trace v1.1.5 on 2.6.24-rc7
Signed-off-by: Ingo Molnar <mingo@elte.hu>
--------------------------------------------------------------------
 latency: 100 us, #3/3, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2)
    -----------------
    | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0)
    -----------------
 => started at: _spin_lock_irqsave+0x2a/0xb7
 => ended at:   _spin_unlock_irqrestore+0x32/0x5f

                 _------=> CPU#
                / _-----=> irqs-off
               | / _----=> need-resched
               || / _---=> hardirq/softirq
               ||| / _--=> preempt-depth
               |||| /
               |||||     delay
   cmd     pid ||||| time  |   caller
      \   /    |||||   \   |   /
 swapper-0     1d.s3    0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000])
 swapper-0     1d.s3  100us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000])
 swapper-0     1d.s3  100us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f)

vim:ft=help
=======

And this is a trace with ftrace_enabled == 1

=======
preemption latency trace v1.1.5 on 2.6.24-rc7
--------------------------------------------------------------------
 latency: 102 us, #12/12, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2)
    -----------------
    | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0)
    -----------------
 => started at: _spin_lock_irqsave+0x2a/0xb7
 => ended at:   _spin_unlock_irqrestore+0x32/0x5f

                 _------=> CPU#
                / _-----=> irqs-off
               | / _----=> need-resched
               || / _---=> hardirq/softirq
               ||| / _--=> preempt-depth
               |||| /
               |||||     delay
   cmd     pid ||||| time  |   caller
      \   /    |||||   \   |   /
 swapper-0     1dNs3    0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000])
 swapper-0     1dNs3   46us : e1000_read_phy_reg+0x16/0x225 [e1000] (e1000_update_stats+0x5e2/0x64c [e1000])
 swapper-0     1dNs3   46us : e1000_swfw_sync_acquire+0x10/0x99 [e1000] (e1000_read_phy_reg+0x49/0x225 [e1000])
 swapper-0     1dNs3   46us : e1000_get_hw_eeprom_semaphore+0x12/0xa6 [e1000] (e1000_swfw_sync_acquire+0x36/0x99 [e1000])
 swapper-0     1dNs3   47us : __const_udelay+0x9/0x47 (e1000_read_phy_reg+0x116/0x225 [e1000])
 swapper-0     1dNs3   47us+: __delay+0x9/0x50 (__const_udelay+0x45/0x47)
 swapper-0     1dNs3   97us : preempt_schedule+0xc/0x84 (__delay+0x4e/0x50)
 swapper-0     1dNs3   98us : e1000_swfw_sync_release+0xc/0x55 [e1000] (e1000_read_phy_reg+0x211/0x225 [e1000])
 swapper-0     1dNs3   99us+: e1000_put_hw_eeprom_semaphore+0x9/0x35 [e1000] (e1000_swfw_sync_release+0x50/0x55 [e1000])
 swapper-0     1dNs3  101us : _spin_unlock_irqrestore+0xe/0x5f (e1000_update_stats+0x641/0x64c [e1000])
 swapper-0     1dNs3  102us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000])
 swapper-0     1dNs3  102us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f)

vim:ft=help
=======

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:32:46 +02:00
Dale Farnsworth 1481197b50 Subject: lockdep: include all lock classes in all_lock_classes
Add each lock class to the all_lock_classes list when it is
first registered.

Previously, lock classes were added to all_lock_classes when
the lock class was first used.  Since one of the uses of the
list is to find unused locks, this didn't work well.

Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-02-25 23:03:02 +01:00
Ingo Molnar 82a1fcb902 softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasks
this patch extends the soft-lockup detector to automatically
detect hung TASK_UNINTERRUPTIBLE tasks. Such hung tasks are
printed the following way:

 ------------------>
 INFO: task prctl:3042 blocked for more than 120 seconds.
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message
 prctl         D fd5e3793     0  3042   2997
        f6050f38 00000046 00000001 fd5e3793 00000009 c06d8264 c06dae80 00000286
        f6050f40 f6050f00 f7d34d90 f7d34fc8 c1e1be80 00000001 f6050000 00000000
        f7e92d00 00000286 f6050f18 c0489d1a f6050f40 00006605 00000000 c0133a5b
 Call Trace:
  [<c04883a5>] schedule_timeout+0x6d/0x8b
  [<c04883d8>] schedule_timeout_uninterruptible+0x15/0x17
  [<c0133a76>] msleep+0x10/0x16
  [<c0138974>] sys_prctl+0x30/0x1e2
  [<c0104c52>] sysenter_past_esp+0x5f/0xa5
  =======================
 2 locks held by prctl/3042:
 #0:  (&sb->s_type->i_mutex_key#5){--..}, at: [<c0197d11>] do_fsync+0x38/0x7a
 #1:  (jbd_handle){--..}, at: [<c01ca3d2>] journal_start+0xc7/0xe9
 <------------------

the current default timeout is 120 seconds. Such messages are printed
up to 10 times per bootup. If the system has crashed already then the
messages are not printed.

if lockdep is enabled then all held locks are printed as well.

this feature is a natural extension to the softlockup-detector (kernel
locked up without scheduling) and to the NMI watchdog (kernel locked up
with IRQs disabled).

[ Gautham R Shenoy <ego@in.ibm.com>: CPU hotplug fixes. ]
[ Andrew Morton <akpm@linux-foundation.org>: build warning fix. ]

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2008-01-25 21:08:02 +01:00
Arjan van de Ven fabe874a48 lockdep: fix kernel crash on module unload
Michael Wu noticed in his lkml post at

    http://marc.info/?l=linux-kernel&m=119396182726091&w=2

that certain wireless drivers ended up having their name in module
memory, which would then crash the kernel on module unload.

The patch he proposed was a bit clumsy in that it increased the size of
a lockdep entry significantly; the patch below tries another approach,
it checks, on module teardown, if the name of a class is in module space
and then zaps the class.  This is very similar to what we already do
with keys that are in module space.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-24 08:01:09 -08:00
Nick Piggin 5a26db5bd2 lockdep: fix internal double unlock during self-test
Lockdep, during self-test (when it was simulating double unlocks) was
sometimes unconditionally unlocking a spinlock when it had not been
locked. This won't work for ticket locks.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2008-01-16 09:51:58 +01:00
Ingo Molnar 5f9fa8a62d lockdep: make cli/sti annotation warnings clearer
make cli/sti annotation warnings easier to interpret.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2007-12-07 19:02:47 +01:00
Oleg Nesterov 54561783ee lockdep: in_range() fix
Torsten Kaiser wrote:

| static inline int in_range(const void *start, const void *addr, const void *end)
| {
|         return addr >= start && addr <= end;
| }
| This  will return true, if addr is in the range of start (including)
| to end (including).
|
| But debug_check_no_locks_freed() seems does:
| const void *mem_to = mem_from + mem_len
| -> mem_to is the last byte of the freed range, that fits in_range
| lock_from = (void *)hlock->instance;
| -> first byte of the lock
| lock_to = (void *)(hlock->instance + 1);
| -> first byte of the next lock, not last byte of the lock that is being checked!
|
| The test is:
| if (!in_range(mem_from, lock_from, mem_to) &&
|                                         !in_range(mem_from, lock_to, mem_to))
|                         continue;
| So it tests, if the first byte of the lock is in the range that is freed ->OK
| And if the first byte of the *next* lock is in the range that is freed
| -> Not OK.

We can also simplify in_range checks, we need only 2 comparisons, not 4.
If the lock is not in memory range, it should be either at the left of range
or at the right.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2007-12-05 15:46:09 +01:00
Ingo Molnar 856848737b lockdep: fix debug_show_all_locks()
fix the oops that can be seen in:

   http://bugzilla.kernel.org/attachment.cgi?id=13828&action=view

it is not safe to print the locks of running tasks.

(even with this fix we have a small race - but this is a debug
 function after all.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2007-12-05 15:46:09 +01:00
Gautham R Shenoy 17aacfb9cd lockdep: fix a typo in the __lock_acquire comment
Fix a typo in the __lock_acquire comment.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-28 20:47:01 +01:00
Pavel Emelyanov ba25f9dcc4 Use helpers to obtain task pid in printks
The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.

The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.

[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:43 -07:00
Johannes Berg 4e6045f134 workqueue: debug flushing deadlocks with lockdep
In the following scenario:

code path 1:
  my_function() -> lock(L1); ...; flush_workqueue(); ...

code path 2:
  run_workqueue() -> my_work() -> ...; lock(L1); ...

you can get a deadlock when my_work() is queued or running
but my_function() has acquired L1 already.

This patch adds a pseudo-lock to each workqueue to make lockdep
warn about this scenario.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:38 -07:00
Peter Zijlstra b351d164e8 lockdep: syscall exit check
Provide a check to validate that we do not hold any locks when switching
back to user-space.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-11 22:11:12 +02:00
Gregory Haskins 3aa416b07f lockdep: fix mismatched lockdep_depth/curr_chain_hash
It is possible for the current->curr_chain_key to become inconsistent with the
current index if the chain fails to validate.  The end result is that future
lock_acquire() operations may inadvertently fail to find a hit in the cache
resulting in a new node being added to the graph for every acquire.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-11 22:11:11 +02:00
Johannes Berg c71063c9c9 lockdep debugging: give stacktrace for init_error
When I started adding support for lockdep to 64-bit powerpc, I got a
lockdep_init_error and with this patch was able to pinpoint why and where
to put lockdep_init().  Let's support this generally for others adding
lockdep support to their architecture.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:49 -07:00
Peter Zijlstra 96645678cd lockstat: measure lock bouncing
__acquire
        |
       lock _____
        |        \
        |    __contended
        |         |
        |        wait
        | _______/
        |/
        |
   __acquired
        |
   __release
        |
     unlock

We measure acquisition and contention bouncing.

This is done by recording a cpu stamp in each lock instance.

Contention bouncing requires the cpu stamp to be set on acquisition. Hence we
move __acquired into the generic path.

__acquired is then used to measure acquisition bouncing by comparing the
current cpu with the old stamp before replacing it.

__contended is used to measure contention bouncing (only useful for preemptable
locks)

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:49 -07:00
Peter Zijlstra 4b32d0a4e9 lockdep: various fixes
- update the copyright notices
 - use the default hash function
 - fix a thinko in a BUILD_BUG_ON
 - add a WARN_ON to spot inconsitent naming
 - fix a termination issue in /proc/lock_stat

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:49 -07:00
Peter Zijlstra c46261de0d lockstat: human readability tweaks
Present all this fancy new lock statistics information:

*warning, _wide_ output ahead*

(output edited for purpose of brevity)

 # cat /proc/lock_stat
lock_stat version 0.1
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
                              class name    contentions   waittime-min   waittime-max waittime-total   acquisitions   holdtime-min   holdtime-max holdtime-total
-----------------------------------------------------------------------------------------------------------------------------------------------------------------

                         &inode->i_mutex:         14458           6.57      398832.75     2469412.23        6768876           0.34    11398383.65   339410830.89
                         ---------------
                         &inode->i_mutex           4486          [<ffffffff802a08f9>] pipe_wait+0x86/0x8d
                         &inode->i_mutex              0          [<ffffffff802a01e8>] pipe_write_fasync+0x29/0x5d
                         &inode->i_mutex              0          [<ffffffff802a0e18>] pipe_read+0x74/0x3a5
                         &inode->i_mutex              0          [<ffffffff802a1a6a>] do_lookup+0x81/0x1ae

.................................................................................................................................................................

              &inode->i_data.tree_lock-W:           491           0.27          62.47         493.89        2477833           0.39         468.89     1146584.25
              &inode->i_data.tree_lock-R:            65           0.44           4.27          48.78       26288792           0.36         184.62    10197458.24
              --------------------------
                &inode->i_data.tree_lock             46          [<ffffffff80277095>] __do_page_cache_readahead+0x69/0x24f
                &inode->i_data.tree_lock             31          [<ffffffff8026f9fb>] add_to_page_cache+0x31/0xba
                &inode->i_data.tree_lock              0          [<ffffffff802770ee>] __do_page_cache_readahead+0xc2/0x24f
                &inode->i_data.tree_lock              0          [<ffffffff8026f6e4>] find_get_page+0x1a/0x58

.................................................................................................................................................................

                      proc_inum_idr.lock:             0           0.00           0.00           0.00             36           0.00          65.60         148.26
                        proc_subdir_lock:             0           0.00           0.00           0.00        3049859           0.00         106.81     1563212.42
                        shrinker_rwsem-W:             0           0.00           0.00           0.00              5           0.00           1.73           3.68
                        shrinker_rwsem-R:             0           0.00           0.00           0.00            633           2.57         246.57       10909.76

'contentions' and 'acquisitions' are the number of such events measured (since
the last reset). The waittime- and holdtime- (min, max, total) numbers are
presented in microseconds.

If there are any contention points, the lock class is presented in the block
format (as i_mutex and tree_lock above), otherwise a single line of output is
presented.

The output is sorted on absolute number of contentions (read + write), this
should get the worst offenders presented first, so that:

 # grep : /proc/lock_stat | head

will quickly show who's bad.

The stats can be reset using:

 # echo 0 > /proc/lock_stat

[bunk@stusta.de: make 2 functions static]
[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:49 -07:00
Peter Zijlstra f20786ff4d lockstat: core infrastructure
Introduce the core lock statistics code.

Lock statistics provides lock wait-time and hold-time (as well as the count
of corresponding contention and acquisitions events). Also, the first few
call-sites that encounter contention are tracked.

Lock wait-time is the time spent waiting on the lock. This provides insight
into the locking scheme, that is, a heavily contended lock is indicative of
a too coarse locking scheme.

Lock hold-time is the duration the lock was held, this provides a reference for
the wait-time numbers, so they can be put into perspective.

  1)
    lock
  2)
    ... do stuff ..
    unlock
  3)

The time between 1 and 2 is the wait-time. The time between 2 and 3 is the
hold-time.

The lockdep held-lock tracking code is reused, because it already collects locks
into meaningful groups (classes), and because it is an existing infrastructure
for lock instrumentation.

Currently lockdep tracks lock acquisition with two hooks:

  lock()
    lock_acquire()
    _lock()

 ... code protected by lock ...

  unlock()
    lock_release()
    _unlock()

We need to extend this with two more hooks, in order to measure contention.

  lock_contended() - used to measure contention events
  lock_acquired()  - completion of the contention

These are then placed the following way:

  lock()
    lock_acquire()
    if (!_try_lock())
      lock_contended()
      _lock()
      lock_acquired()

 ... do locked stuff ...

  unlock()
    lock_release()
    _unlock()

(Note: the try_lock() 'trick' is used to avoid instrumenting all platform
       dependent lock primitive implementations.)

It is also possible to toggle the two lockdep features at runtime using:

  /proc/sys/kernel/prove_locking
  /proc/sys/kernel/lock_stat

(esp. turning off the O(n^2) prove_locking functionaliy can help)

[akpm@linux-foundation.org: build fixes]
[akpm@linux-foundation.org: nuke unneeded ifdefs]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:49 -07:00
Peter Zijlstra 8e18257d29 lockdep: reduce the ifdeffery
Move code around to get fewer but larger #ifdef sections.  Break some
in-function #ifdefs out into their own functions.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:49 -07:00
Peter Zijlstra ca58abcb4a lockdep: sanitise CONFIG_PROVE_LOCKING
Ensure that all of the lock dependency tracking code is under
CONFIG_PROVE_LOCKING.  This allows us to use the held lock tracking code for
other purposes.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:49 -07:00
Tejun Heo 9281acea6a kallsyms: make KSYM_NAME_LEN include space for trailing '\0'
KSYM_NAME_LEN is peculiar in that it does not include the space for the
trailing '\0', forcing all users to use KSYM_NAME_LEN + 1 when allocating
buffer.  This is nonsense and error-prone.  Moreover, when the caller
forgets that it's very likely to subtly bite back by corrupting the stack
because the last position of the buffer is always cleared to zero.

This patch increments KSYM_NAME_LEN by one and updates code accordingly.

* off-by-one bug in asm-powerpc/kprobes.h::kprobe_lookup_name() macro
  is fixed.

* Where MODULE_NAME_LEN and KSYM_NAME_LEN were used together,
  MODULE_NAME_LEN was treated as if it didn't include space for the
  trailing '\0'.  Fix it.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Paulo Marques <pmarques@grupopie.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:03 -07:00
Jarek Poplawski 4ff773bbde lockdep: removed unused ip argument in mark_lock & mark_held_locks
It looks like a remainder from designing...

Signed-off-by: Jarek Poplawski <jarkao@o2.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:13 -07:00
Jarek Poplawski 9e860d000a lockdep: lookup_chain_cache comment errata
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:11 -07:00
Alexey Dobriyan ffb4512276 Simplify kallsyms_lookup()
Several kallsyms_lookup() pass dummy arguments but only need, say, module's
name.  Make kallsyms_lookup() accept NULLs where possible.

Also, makes picture clearer about what interfaces are needed for all symbol
resolving business.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:08 -07:00
Christoph Hellwig ab1b6f03a1 simplify the stacktrace code
Simplify the stacktrace code:

 - remove the unused task argument to save_stack_trace, it's always
   current
 - remove the all_contexts flag, it's alwasy 0

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andi Kleen <ak@suse.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:14:58 -07:00
Jarek Poplawski 9c35dd7f8b [PATCH] lockdep: debug_show_all_locks & debug_show_held_locks vs. debug_locks
lockdep's data shouldn't be used when debug_locks == 0 because it's not
updated after this, so it's more misleading than helpful.

PS: probably lockdep's current-> fields should be reset after it turns
debug_locks off: so, after printing a bug report, but before return from
exported functions, but there are really a lot of these possibilities (e.g.
 after DEBUG_LOCKS_WARN_ON), so, something could be missed.  (Of course
direct use of this fields isn't recommended either.)

Reported-by: Folkert van Heusden <folkert@vanheusden.com>
Inspired-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-22 19:39:06 -07:00
Sam Ravnborg 1499993cc7 [PATCH] fix section mismatch warning in lockdep
lockdep_init() is marked __init but used in several places
outside __init code. This causes following warnings:
$ scripts/mod/modpost kernel/lockdep.o
WARNING: kernel/built-in.o - Section mismatch: reference to .init.text:lockdep_init from .text.lockdep_init_map after 'lockdep_init_map' (at offset 0x105)
WARNING: kernel/built-in.o - Section mismatch: reference to .init.text:lockdep_init from .text.lockdep_reset_lock after 'lockdep_reset_lock' (at offset 0x35)
WARNING: kernel/built-in.o - Section mismatch: reference to .init.text:lockdep_init from .text.__lock_acquire after '__lock_acquire' (at offset 0xb2)

The warnings are less obviously due to heavy inlining by gcc - this is not
altered.

Fix the section mismatch warnings by removing the __init marking, which
seems obviously wrong.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-01 14:53:37 -08:00
Jarek Poplawski 60e114d113 [PATCH] lockdep: debug_locks check after check_chain_key
In __lock_acquire check_chain_key can turn off debug_locks, so check is
needed to assure proper return code.

Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-20 17:10:14 -08:00
Jason Baron 068135e635 [PATCH] lockdep: add graph depth information to /proc/lockdep
Generate locking graph information into /proc/lockdep, for lock hierarchy
documentation and visualization purposes.

sample output:

 c089fd5c OPS:     138 FD:   14 BD:    1 --..: &tty->termios_mutex
  -> [c07a3430] tty_ldisc_lock
  -> [c07a37f0] &port_lock_key
  -> [c07afdc0] &rq->rq_lock_key#2

The lock classes listed are all the first-hop lock dependencies that
lockdep has seen so far.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:26 -08:00
Jarek Poplawski 381a229209 [PATCH] lockdep: more unlock-on-error fixes
- returns after DEBUG_LOCKS_WARN_ON added in 3 places

- debug_locks checking after lookup_chain_cache() added in
  __lock_acquire()

- locking for testing and changing global variable max_lockdep_depth
  added in __lock_acquire()

From: Ingo Molnar <mingo@elte.hu>

My __acquire_lock() cleanup introduced a locking bug: on SMP systems we'd
release a non-owned graph lock.  Fix this by moving the graph unlock back,
and by leaving the max_lockdep_depth variable update possibly racy.  (we
dont care, it's just statistics)

Also add some minimal debugging code to graph_unlock()/graph_lock(),
which caught this locking bug.

Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:26 -08:00
Andrew Morton 755cd90029 [PATCH] lockdep: printk warning fix
kernel/lockdep.c: In function `lookup_chain_cache':
kernel/lockdep.c:1339: warning: long long unsigned int format, u64 arg (arg 2)
kernel/lockdep.c:1344: warning: long long unsigned int format, u64 arg (arg 2)

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-30 10:56:43 -08:00
Ingo Molnar 74c383f140 [PATCH] lockdep: fix possible races while disabling lock-debugging
Jarek Poplawski noticed that lockdep global state could be accessed in a
racy way if one CPU did a lockdep assert (shutting lockdep down), while the
other CPU would try to do something that changes its global state.

This patch fixes those races and cleans up lockdep's internal locking by
adding a graph_lock()/graph_unlock()/debug_locks_off_graph_unlock helpers.

(Also note that as we all know the Linux kernel is, by definition, bug-free
and perfect, so this code never triggers, so these fixes are highly
theoretical.  I wrote this patch for aesthetic reasons alone.)

[akpm@osdl.org: build fix]
[jarkao2@o2.pl: build fix's refix]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:50 -08:00
Ingo Molnar 3117df0453 [PATCH] lockdep: print irq-trace info on asserts
When we print an assert due to scheduling-in-atomic bugs, and if lockdep
is enabled, then the IRQ tracing information of lockdep can be printed
to pinpoint the code location that disabled interrupts. This saved me
quite a bit of debugging time in cases where the backtrace did not
identify the irq-disabling site well enough.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:50 -08:00
Ingo Molnar 27c3b23226 [PATCH] lockdep: use chain hash on CONFIG_DEBUG_LOCKDEP too
CONFIG_DEBUG_LOCKDEP is unacceptably slow because it does not utilize
the chain-hash. Turn the chain-hash back on in this case too.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:50 -08:00
Ingo Molnar 33e94e960b [PATCH] lockdep: clean up VERY_VERBOSE define
Cleanup: the VERY_VERBOSE define was unnecessarily dependent on #ifdef VERBOSE
- while the VERBOSE switch is 0 or 1 (always defined).

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:50 -08:00
Ingo Molnar 23d95a03d6 [PATCH] lockdep: improve lockdep_reset()
Clear all the chains during lockdep_reset().  This fixes some locking-selftest
false positives i saw on -rt.  (never saw those on mainline though, but it
could happen.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:50 -08:00
Ingo Molnar 81fc685a89 [PATCH] lockdep: improve verbose messages
Make verbose lockdep messages (off by default) more informative by printing
out the hash chain key.  (this patch was what helped me catch the earlier
lockdep hash-collision bug)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:50 -08:00
Ingo Molnar a664089741 [PATCH] lockdep: filter off by default
Fix typo in the class_filter() function.  (filtering is not used by default so
this only affects lockdep-internal debugging cases)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:50 -08:00
Linus Torvalds 4522d58275 Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6
* 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6: (156 commits)
  [PATCH] x86-64: Export smp_call_function_single
  [PATCH] i386: Clean up smp_tune_scheduling()
  [PATCH] unwinder: move .eh_frame to RODATA
  [PATCH] unwinder: fully support linker generated .eh_frame_hdr section
  [PATCH] x86-64: don't use set_irq_regs()
  [PATCH] x86-64: check vector in setup_ioapic_dest to verify if need setup_IO_APIC_irq
  [PATCH] x86-64: Make ix86 default to HIGHMEM4G instead of NOHIGHMEM
  [PATCH] i386: replace kmalloc+memset with kzalloc
  [PATCH] x86-64: remove remaining pc98 code
  [PATCH] x86-64: remove unused variable
  [PATCH] x86-64: Fix constraints in atomic_add_return()
  [PATCH] x86-64: fix asm constraints in i386 atomic_add_return
  [PATCH] x86-64: Correct documentation for bzImage protocol v2.05
  [PATCH] x86-64: replace kmalloc+memset with kzalloc in MTRR code
  [PATCH] x86-64: Fix numaq build error
  [PATCH] x86-64: include/asm-x86_64/cpufeature.h isn't a userspace header
  [PATCH] unwinder: Add debugging output to the Dwarf2 unwinder
  [PATCH] x86-64: Clarify error message in GART code
  [PATCH] x86-64: Fix interrupt race in idle callback (3rd try)
  [PATCH] x86-64: Remove unwind stack pointer alignment forcing again
  ...

Fixed conflict in include/linux/uaccess.h manually

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:59:11 -08:00
Ingo Molnar 70e4506765 [PATCH] lockdep: register_lock_class() fix
The hash_lock must only ever be taken with irqs disabled.  This happens in
all the important places, except one codepath: register_lock_class().  The
race should trigger rarely because register_lock_class() is quite rare and
single-threaded (happens during init most of the time).

The fix is to disable irqs.

( bug found live in -rt: there preemption is alot more agressive and
  preempting with the hash-lock held caused a lockup.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:46 -08:00
Adrian Bunk ebe7e5fe4b [PATCH] remove kernel/lockdep.c:lockdep_internal
Remove the no longer used lockdep_internal().

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:39 -08:00
Jarek Poplawski b23984d0a1 [PATCH] lockdep: misc fixes in lockdep.c
- numeric string size replaced with constant in print_lock_name and
   print_lockdep_cache,

 - return on null pointer in print_lock_dependencies,

 - one more lockdep return with 0 with unlocking fix in mark_lock.

Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:33 -08:00
Jarek Poplawski 910b1b2e6d [PATCH] lockdep: internal locking fixes
Here are mainly some lockdep returns with 0 with unlocking fixes.

Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:33 -08:00
Peter Zijlstra ed07536ed6 [PATCH] lockdep: annotate nfs/nfsd in-kernel sockets
Stick NFS sockets in their own class to avoid some lockdep warnings.  NFS
sockets are never exposed to user-space, and will hence not trigger certain
code paths that would otherwise pose deadlock scenarios.

[akpm@osdl.org: cleanups]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Dickson <SteveD@redhat.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Acked-by: Neil Brown <neilb@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
[ Fixed patch corruption by quilt, pointed out by Peter Zijlstra ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:30 -08:00
Andi Kleen eef5e0d185 [PATCH] unwinder: Remove lockdep disabling of nested locks for unwinder
Shouldn't be needed anymore since __kernel_text_address
is used unconditionally on x86-64

Signed-off-by: Andi Kleen <ak@suse.de>
2006-12-07 02:14:12 +01:00
Ingo Molnar 1ff5683043 [PATCH] lockdep: fix static keys in module-allocated percpu areas
lockdep got confused by certain locks in modules:

 INFO: trying to register non-static key.
 the code is fine but needs lockdep annotation.
 turning off the locking correctness validator.

 Call Trace:
  [<ffffffff8026f40d>] dump_trace+0xaa/0x3f2
  [<ffffffff8026f78f>] show_trace+0x3a/0x60
  [<ffffffff8026f9d1>] dump_stack+0x15/0x17
  [<ffffffff802abfe8>] __lock_acquire+0x724/0x9bb
  [<ffffffff802ac52b>] lock_acquire+0x4d/0x67
  [<ffffffff80267139>] rt_spin_lock+0x3d/0x41
  [<ffffffff8839ed3f>] :ip_conntrack:__ip_ct_refresh_acct+0x131/0x174
  [<ffffffff883a1334>] :ip_conntrack:udp_packet+0xbf/0xcf
  [<ffffffff8839f9af>] :ip_conntrack:ip_conntrack_in+0x394/0x4a7
  [<ffffffff8023551f>] nf_iterate+0x41/0x7f
  [<ffffffff8025946a>] nf_hook_slow+0x64/0xd5
  [<ffffffff802369a2>] ip_rcv+0x24e/0x506
  [...]

Steven Rostedt found the bug: static_obj() check did not take
PERCPU_ENOUGH_ROOM into account, so in-module DEFINE_PER_CPU-area locks
were triggering this message.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-17 11:10:37 -08:00
Linus Torvalds 43f82216f0 Merge git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: fm801-gp - handle errors from pci_enable_device()
  Input: gameport core - handle errors returned by device_bind_driver()
  Input: serio core - handle errors returned by device_bind_driver()
  Lockdep: fix compile error in drivers/input/serio/serio.c
  Input: serio - add lockdep annotations
  Lockdep: add lockdep_set_class_and_subclass() and lockdep_set_subclass()
  Input: atkbd - supress "too many keys" error message
  Input: i8042 - supress ACK/NAKs when blinking during panic
  Input: add missing exports to fix modular build
2006-10-17 08:56:43 -07:00
Ingo Molnar ca268c691d [PATCH] lockdep: increase max allowed recursion depth
In general, lockdep warnings are intended to be non-fatal, so I have put in
various practical limits on internal data structure failure modes.  We haven't
had a /single/ lockdep-internal crash ever since lockdep went upstream [the
unwinder crashes are outside of lockdep], and that's largely due to the good
internal checks it does.

Recursion within the dependency graph is currently limited to 20, that's
probably not enough on some many-CPU boxes - this patch doubles it to 40.  I
have written the lockdep functions to have as small stackframes as possible,
so 40 should be OK too.  (The practical recursion limit should be somewhere
between 100 and 200 entries.  If we hit that then I'll change the algorithm to
be iteration-based.  Graph walking logic is so easy to program via recursion,
so i'd like to keep recursion as long as possible.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17 08:18:42 -07:00
Alexey Dobriyan 3dc3099a9b [PATCH] lockdep: use BUILD_BUG_ON
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11 11:14:24 -07:00
Peter Zijlstra 4dfbb9d8c6 Lockdep: add lockdep_set_class_and_subclass() and lockdep_set_subclass()
This annotation makes it possible to assign a subclass on lock init. This
annotation is meant to reduce the _nested() annotations by assigning a
default subclass.

One could do without this annotation and rely on lockdep_set_class()
exclusively, but that would require a manual stack of struct lock_class_key
objects.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2006-10-11 01:45:14 -04:00
Serge E. Hallyn 96b644bdec [PATCH] namespaces: utsname: use init_utsname when appropriate
In some places, particularly drivers and __init code, the init utsns is the
appropriate one to use.  This patch replaces those with a the init_utsname
helper.

Changes: Removed several uses of init_utsname().  Hope I picked all the
	right ones in net/ipv4/ipconfig.c.  These are now changed to
	utsname() (the per-process namespace utsname) in the previous
	patch (2/7)

[akpm@osdl.org: CIFS fix]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02 07:57:21 -07:00
Ingo Molnar 03cbc358aa [PATCH] lockdep core: improve the lock-chain-hash
With CONFIG_DEBUG_LOCK_ALLOC turned off i was getting sporadic failures in
the locking self-test:

  ------------>
  | Locking API testsuite:
  ----------------------------------------------------------------------------
                                   | spin |wlock |rlock |mutex | wsem | rsem |
    --------------------------------------------------------------------------
                       A-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                   A-B-B-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
               A-B-B-C-C-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
               A-B-C-A-B-C deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
           A-B-B-C-C-D-D-A deadlock:  ok  |FAILED|  ok  |  ok  |  ok  |  ok  |
           A-B-C-D-B-D-D-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
           A-B-C-D-B-C-D-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |FAILED|

after much debugging it turned out to be caused by accidental chain-hash
key collisions.  The current hash is:

 #define iterate_chain_key(key1, key2) \
	(((key1) << MAX_LOCKDEP_KEYS_BITS/2) ^ \
	((key1) >> (64-MAX_LOCKDEP_KEYS_BITS/2)) ^ \
 	(key2))

where MAX_LOCKDEP_KEYS_BITS is 11.  This hash is pretty good as it will
shift by 5 bits in every iteration, where every new ID 'mixed' into the
hash would have up to 11 bits.  But because there was a 6 bits overlap
between subsequent IDs and their high bits tended to be similar, there was
a chance for accidental chain-hash collision for a low number of locks
held.

the solution is to shift by 11 bits:

 #define iterate_chain_key(key1, key2) \
	(((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
	((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
 	(key2))

This keeps the hash perfect up to 5 locks held, but even above that the
hash is still good because 11 bits is a relative prime to the total 64
bits, so a complete match will only occur after 64 held locks (which doesnt
happen in Linux).  Even after 5 locks held, entropy of the 5 IDs mixed into
the hash is already good enough so that overlap doesnt generate a colliding
hash ID.

with this change the false positives went away.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:25 -07:00
Dave Jones 99de055ac0 [PATCH] lockdep: print kernel version
Lets do the same thing we do for oopses - print out the version in the
report.  It's an extra line of output though.  We could tack it on the end
of the INFO: lines, but that screws up Ingo's pretty output.

Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:13 -07:00
Andi Kleen 3fa7c794fe [PATCH] Avoid recursion in lockdep when stack tracer takes locks
The new dwarf2 unwinder needs to take locks to do backtraces
inside modules. This patch makes sure lockdep which calls
stacktrace is not reentered.

Thanks to Ingo for suggesting this simpler approach.

Cc: mingo@elte.hu
Signed-off-by: Andi Kleen <ak@suse.de>
2006-09-26 10:52:34 +02:00
Andi Kleen 5a1b3999d6 [PATCH] x86: Some preparationary cleanup for stack trace
- Remove unused all_contexts parameter
No caller used it
- Move skip argument into the structure (needed for
followon patches)

Cc: mingo@elte.hu

Signed-off-by: Andi Kleen <ak@suse.de>
2006-09-26 10:52:34 +02:00
Ingo Molnar d6d897cec2 [PATCH] lockdep: core, reduce per-lock class-cache size
lockdep_map is embedded into every lock, which blows up data structure
sizes all around the kernel.  Reduce the class-cache to be for the default
class only - that is used in 99.9% of the cases and even if we dont have a
class cached, the lookup in the class-hash is lockless.

This change reduces the per-lock dep_map overhead by 56 bytes on 64-bit
platforms and by 28 bytes on 32-bit platforms.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:14 -07:00
Arjan van de Ven 55794a412f [PATCH] lockdep: improve debug output
Make lockdep print which lock is held, in the "kfree() of a live lock"
scenario.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:14 -07:00
Andi Kleen f9829cceb6 [PATCH] Minor cleanup to lockdep.c
- Use printk formatting for indentation
- Don't leave NTFS in the default event filter

Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:14 -07:00
Ingo Molnar 6c9076ec9c [PATCH] lockdep: allow read_lock() recursion of same class
From: Ingo Molnar <mingo@elte.hu>

lockdep so far only allowed read-recursion for the same lock instance.
This is enough in the overwhelming majority of cases, but a hostap case
triggered and reported by Miles Lane relies on same-class
different-instance recursion.  So we relax the restriction on read-lock
recursion.

(This change does not allow rwsem read-recursion, which is still
forbidden.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:04 -07:00
Ingo Molnar fbb9ce9530 [PATCH] lockdep: core
Do 'make oldconfig' and accept all the defaults for new config options -
reboot into the kernel and if everything goes well it should boot up fine and
you should have /proc/lockdep and /proc/lockdep_stats files.

Typically if the lock validator finds some problem it will print out
voluminous debug output that begins with "BUG: ..." and which syslog output
can be used by kernel developers to figure out the precise locking scenario.

What does the lock validator do?  It "observes" and maps all locking rules as
they occur dynamically (as triggered by the kernel's natural use of spinlocks,
rwlocks, mutexes and rwsems).  Whenever the lock validator subsystem detects a
new locking scenario, it validates this new rule against the existing set of
rules.  If this new rule is consistent with the existing set of rules then the
new rule is added transparently and the kernel continues as normal.  If the
new rule could create a deadlock scenario then this condition is printed out.

When determining validity of locking, all possible "deadlock scenarios" are
considered: assuming arbitrary number of CPUs, arbitrary irq context and task
context constellations, running arbitrary combinations of all the existing
locking scenarios.  In a typical system this means millions of separate
scenarios.  This is why we call it a "locking correctness" validator - for all
rules that are observed the lock validator proves it with mathematical
certainty that a deadlock could not occur (assuming that the lock validator
implementation itself is correct and its internal data structures are not
corrupted by some other kernel subsystem).  [see more details and conditionals
of this statement in include/linux/lockdep.h and
Documentation/lockdep-design.txt]

Furthermore, this "all possible scenarios" property of the validator also
enables the finding of complex, highly unlikely multi-CPU multi-context races
via single single-context rules, increasing the likelyhood of finding bugs
drastically.  In practical terms: the lock validator already found a bug in
the upstream kernel that could only occur on systems with 3 or more CPUs, and
which needed 3 very unlikely code sequences to occur at once on the 3 CPUs.
That bug was found and reported on a single-CPU system (!).  So in essence a
race will be found "piecemail-wise", triggering all the necessary components
for the race, without having to reproduce the race scenario itself!  In its
short existence the lock validator found and reported many bugs before they
actually caused a real deadlock.

To further increase the efficiency of the validator, the mapping is not per
"lock instance", but per "lock-class".  For example, all struct inode objects
in the kernel have inode->inotify_mutex.  If there are 10,000 inodes cached,
then there are 10,000 lock objects.  But ->inotify_mutex is a single "lock
type", and all locking activities that occur against ->inotify_mutex are
"unified" into this single lock-class.  The advantage of the lock-class
approach is that all historical ->inotify_mutex uses are mapped into a single
(and as narrow as possible) set of locking rules - regardless of how many
different tasks or inode structures it took to build this set of rules.  The
set of rules persist during the lifetime of the kernel.

To see the rough magnitude of checking that the lock validator does, here's a
portion of /proc/lockdep_stats, fresh after bootup:

 lock-classes:                            694 [max: 2048]
 direct dependencies:                  1598 [max: 8192]
 indirect dependencies:               17896
 all direct dependencies:             16206
 dependency chains:                    1910 [max: 8192]
 in-hardirq chains:                      17
 in-softirq chains:                     105
 in-process chains:                    1065
 stack-trace entries:                 38761 [max: 131072]
 combined max dependencies:         2033928
 hardirq-safe locks:                     24
 hardirq-unsafe locks:                  176
 softirq-safe locks:                     53
 softirq-unsafe locks:                  137
 irq-safe locks:                         59
 irq-unsafe locks:                      176

The lock validator has observed 1598 actual single-thread locking patterns,
and has validated all possible 2033928 distinct locking scenarios.

More details about the design of the lock validator can be found in
Documentation/lockdep-design.txt, which can also found at:

   http://redhat.com/~mingo/lockdep-patches/lockdep-design.txt

[bunk@stusta.de: cleanups]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:03 -07:00