linux-toradex.git/kernel/locking/lockdep.c, branch v3.15-rc6

asmlinkage: Add explicit __visible to drivers/, lib/, kernel/*

2014-05-05T23:07:46+00:00

As requested by Linus add explicit __visible to the asmlinkage users.
This marks functions visible to assembler.

Tree sweep for rest of tree.

Signed-off-by: Andi Kleen 
Link: http://lkml.kernel.org/r/1398984278-29319-4-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin

Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-03-31T21:13:25+00:00

Pull x86 LTO changes from Peter Anvin:
 "More infrastructure work in preparation for link-time optimization
  (LTO).  Most of these changes is to make sure symbols accessed from
  assembly code are properly marked as visible so the linker doesn't
  remove them.

  My understanding is that the changes to support LTO are still not
  upstream in binutils, but are on the way there.  This patchset should
  conclude the x86-specific changes, and remaining patches to actually
  enable LTO will be fed through the Kbuild tree (other than keeping up
  with changes to the x86 code base, of course), although not
  necessarily in this merge window"

* 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  Kbuild, lto: Handle basic LTO in modpost
  Kbuild, lto: Disable LTO for asm-offsets.c
  Kbuild, lto: Add a gcc-ld script to let run gcc as ld
  Kbuild, lto: add ld-version and ld-ifversion macros
  Kbuild, lto: Drop .number postfixes in modpost
  Kbuild, lto, workaround: Don't warn for initcall_reference in modpost
  lto: Disable LTO for sys_ni
  lto: Handle LTO common symbols in module loader
  lto, workaround: Add workaround for initcall reordering
  lto: Make asmlinkage __visible
  x86, lto: Disable LTO for the x86 VDSO
  initconst, x86: Fix initconst mistake in ts5500 code
  initconst: Fix initconst mistake in dcdbas
  asmlinkage: Make trace_hardirqs_on/off_caller visible
  asmlinkage, x86: Fix 32bit memcpy for LTO
  asmlinkage Make __stack_chk_failed and memcmp visible
  asmlinkage: Mark rwsem functions that can be called from assembler asmlinkage
  asmlinkage: Make main_extable_sort_needed visible
  asmlinkage, mutex: Mark __visible
  asmlinkage: Make trace_hardirq visible
  ...

asmlinkage: Make trace_hardirq visible

2014-02-14T02:13:07+00:00

Can be called from assembler code.

Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Signed-off-by: Andi Kleen 
Link: http://lkml.kernel.org/r/1391845930-28580-6-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin

asmlinkage: Make lockdep_sys_exit asmlinkage

2014-02-14T02:12:54+00:00

lockdep_sys_exit can be called from assembler code, so make it
asmlinkage.

Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Signed-off-by: Andi Kleen 
Link: http://lkml.kernel.org/r/1391845930-28580-5-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin

lockdep: Change mark_held_locks() to check hlock->check instead of lockdep_no_validate

2014-02-09T20:18:59+00:00

The __lockdep_no_validate check in mark_held_locks() adds the subtle
and (afaics) unnecessary difference between no-validate and check==0.
And this looks even more inconsistent because __lock_acquire() skips
mark_irqflags()->mark_lock() if !check.

Change mark_held_locks() to check hlock->check instead.

Signed-off-by: Oleg Nesterov 
Cc: Dave Jones 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Paul McKenney 
Cc: Steven Rostedt 
Cc: Alan Stern 
Cc: Sasha Levin 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20140120182013.GA26505@redhat.com
Signed-off-by: Ingo Molnar

lockdep: Don't create the wrong dependency on hlock->check == 0

2014-02-09T20:18:57+00:00

Test-case:

	DEFINE_MUTEX(m1);
	DEFINE_MUTEX(m2);
	DEFINE_MUTEX(mx);

	void lockdep_should_complain(void)
	{
		lockdep_set_novalidate_class(&mx);

		// m1 -> mx -> m2
		mutex_lock(&m1);
		mutex_lock(&mx);
		mutex_lock(&m2);
		mutex_unlock(&m2);
		mutex_unlock(&mx);
		mutex_unlock(&m1);

		// m2 -> m1 ; should trigger the warning
		mutex_lock(&m2);
		mutex_lock(&m1);
		mutex_unlock(&m1);
		mutex_unlock(&m2);
	}

this doesn't trigger any warning, lockdep can't detect the trivial
deadlock.

This is because lock(&mx) correctly avoids m1 -> mx dependency, it
skips validate_chain() due to mx->check == 0. But lock(&m2) wrongly
adds mx -> m2 and thus m1 -> m2 is not created.

rcu_lock_acquire()->lock_acquire(check => 0) is fine due to read == 2,
so currently only __lockdep_no_validate__ can trigger this problem.

Signed-off-by: Oleg Nesterov 
Cc: Dave Jones 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Paul McKenney 
Cc: Steven Rostedt 
Cc: Alan Stern 
Cc: Sasha Levin 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20140120182010.GA26498@redhat.com
Signed-off-by: Ingo Molnar

lockdep: Make held_lock->check and "int check" argument bool

2014-02-09T20:18:54+00:00

The "int check" argument of lock_acquire() and held_lock->check are
misleading. This is actually a boolean: 2 means "true", everything
else is "false".

And there is no need to pass 1 or 0 to lock_acquire() depending on
CONFIG_PROVE_LOCKING, __lock_acquire() checks prove_locking at the
start and clears "check" if !CONFIG_PROVE_LOCKING.

Note: probably we can simply kill this member/arg. The only explicit
user of check => 0 is rcu_lock_acquire(), perhaps we can change it to
use lock_acquire(trylock =>, read => 2). __lockdep_no_validate means
check => 0 implicitly, but we can change validate_chain() to check
hlock->instance->key instead. Not to mention it would be nice to get
rid of lockdep_set_novalidate_class().

Signed-off-by: Oleg Nesterov 
Cc: Dave Jones 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Paul McKenney 
Cc: Steven Rostedt 
Cc: Alan Stern 
Cc: Sasha Levin 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20140120182006.GA26495@redhat.com
Signed-off-by: Ingo Molnar

lockdep: Be nice about building from userspace

2013-11-27T10:55:20+00:00

Lockdep is an awesome piece of code which detects locking issues
which are relevant both to userspace and kernelspace. We can
easily make lockdep work in userspace since there is really no
kernel spacific magic going on in the code.

All we need is to wrap two functions which are used by lockdep
and are very kernel specific.

Doing that will allow tools located in tools/ to easily utilize
lockdep's code for their own use.

Signed-off-by: Sasha Levin 
Signed-off-by: Peter Zijlstra 
Cc: penberg@kernel.org
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1352753446-24109-1-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar

locking/lockdep: Mark __lockdep_count_forward_deps() as static

2013-11-13T12:50:17+00:00

There are new Sparse warnings:

  >> kernel/locking/lockdep.c:1235:15: sparse: symbol '__lockdep_count_forward_deps' was not declared. Should it be static?
  >> kernel/locking/lockdep.c:1261:15: sparse: symbol '__lockdep_count_backward_deps' was not declared. Should it be static?

Please consider folding the attached diff :-)

Signed-off-by: Fengguang Wu 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/527d1787.ThzXGoUspZWehFDl\%fengguang.wu@intel.com
Signed-off-by: Ingo Molnar

locking: Move the lockdep code to kernel/locking/

2013-11-06T06:55:08+00:00

Suggested-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/n/tip-wl7s3tta5isufzfguc23et06@git.kernel.org
Signed-off-by: Ingo Molnar