linux-toradex.git/drivers/oprofile/buffer_sync.c, branch v3.10.78

mm: use mm->exe_file instead of first VM_EXECUTABLE vma->vm_file

2012-10-09T07:22:18+00:00

Some security modules and oprofile still uses VM_EXECUTABLE for retrieving
a task's executable file.  After this patch they will use mm->exe_file
directly.  mm->exe_file is protected with mm->mmap_sem, so locking stays
the same.

Signed-off-by: Konstantin Khlebnikov 
Acked-by: Chris Metcalf 			[arch/tile]
Acked-by: Tetsuo Handa 	[tomoyo]
Cc: Alexander Viro 
Cc: Carsten Otte 
Cc: Cyrill Gorcunov 
Cc: Eric Paris 
Cc: H. Peter Anvin 
Cc: Hugh Dickins 
Cc: Ingo Molnar 
Acked-by: James Morris 
Cc: Jason Baron 
Cc: Kentaro Takeda 
Cc: Matt Helsley 
Cc: Nick Piggin 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Robert Richter 
Cc: Suresh Siddha 
Cc: Venkatesh Pallipadi 
Acked-by: Linus Torvalds 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oprofile: Fix locking dependency in sync_start()

2011-05-31T14:33:34+00:00

This fixes the A->B/B->A locking dependency, see the warning below.

The function task_exit_notify() is called with (task_exit_notifier)
.rwsem set and then calls sync_buffer() which locks buffer_mutex. In
sync_start() the buffer_mutex was set to prevent notifier functions to
be started before sync_start() is finished. But when registering the
notifier, (task_exit_notifier).rwsem is locked too, but now in
different order than in sync_buffer(). In theory this causes a locking
dependency, what does not occur in practice since task_exit_notify()
is always called after the notifier is registered which means the lock
is already released.

However, after checking the notifier functions it turned out the
buffer_mutex in sync_start() is unnecessary. This is because
sync_buffer() may be called from the notifiers even if sync_start()
did not finish yet, the buffers are already allocated but empty. No
need to protect this with the mutex.

So we fix this theoretical locking dependency by removing buffer_mutex
in sync_start(). This is similar to the implementation before commit:

 750d857 oprofile: fix crash when accessing freed task structs

which introduced the locking dependency.

Lockdep warning:

oprofiled/4447 is trying to acquire lock:
 (buffer_mutex){+.+...}, at: [] sync_buffer+0x31/0x3ec [oprofile]

but task is already holding lock:
 ((task_exit_notifier).rwsem){++++..}, at: [] __blocking_notifier_call_chain+0x39/0x67

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 ((task_exit_notifier).rwsem){++++..}:
       [] lock_acquire+0xf8/0x11e
       [] down_write+0x44/0x67
       [] blocking_notifier_chain_register+0x52/0x8b
       [] profile_event_register+0x2d/0x2f
       [] sync_start+0x47/0xc6 [oprofile]
       [] oprofile_setup+0x60/0xa5 [oprofile]
       [] event_buffer_open+0x59/0x8c [oprofile]
       [] __dentry_open+0x1eb/0x308
       [] nameidata_to_filp+0x60/0x67
       [] do_last+0x5be/0x6b2
       [] path_openat+0xc7/0x360
       [] do_filp_open+0x3d/0x8c
       [] do_sys_open+0x110/0x1a9
       [] sys_open+0x20/0x22
       [] system_call_fastpath+0x16/0x1b

-> #0 (buffer_mutex){+.+...}:
       [] __lock_acquire+0x1085/0x1711
       [] lock_acquire+0xf8/0x11e
       [] mutex_lock_nested+0x63/0x309
       [] sync_buffer+0x31/0x3ec [oprofile]
       [] task_exit_notify+0x16/0x1a [oprofile]
       [] notifier_call_chain+0x37/0x63
       [] __blocking_notifier_call_chain+0x50/0x67
       [] blocking_notifier_call_chain+0x14/0x16
       [] profile_task_exit+0x1a/0x1c
       [] do_exit+0x2a/0x6fc
       [] do_group_exit+0x83/0xae
       [] sys_exit_group+0x17/0x1b
       [] system_call_fastpath+0x16/0x1b

other info that might help us debug this:

1 lock held by oprofiled/4447:
 #0:  ((task_exit_notifier).rwsem){++++..}, at: [] __blocking_notifier_call_chain+0x39/0x67

stack backtrace:
Pid: 4447, comm: oprofiled Not tainted 2.6.39-00007-gcf4d8d4 #10
Call Trace:
 [] print_circular_bug+0xae/0xbc
 [] __lock_acquire+0x1085/0x1711
 [] ? sync_buffer+0x31/0x3ec [oprofile]
 [] lock_acquire+0xf8/0x11e
 [] ? sync_buffer+0x31/0x3ec [oprofile]
 [] ? mark_lock+0x42f/0x552
 [] ? sync_buffer+0x31/0x3ec [oprofile]
 [] mutex_lock_nested+0x63/0x309
 [] ? sync_buffer+0x31/0x3ec [oprofile]
 [] sync_buffer+0x31/0x3ec [oprofile]
 [] ? __blocking_notifier_call_chain+0x39/0x67
 [] ? __blocking_notifier_call_chain+0x39/0x67
 [] task_exit_notify+0x16/0x1a [oprofile]
 [] notifier_call_chain+0x37/0x63
 [] __blocking_notifier_call_chain+0x50/0x67
 [] blocking_notifier_call_chain+0x14/0x16
 [] profile_task_exit+0x1a/0x1c
 [] do_exit+0x2a/0x6fc
 [] ? retint_swapgs+0xe/0x13
 [] do_group_exit+0x83/0xae
 [] sys_exit_group+0x17/0x1b
 [] system_call_fastpath+0x16/0x1b

Reported-by: Marcin Slusarz 
Cc: Carl Love 
Cc:  # .36+
Signed-off-by: Robert Richter

oprofile: Free potentially owned tasks in case of errors

2011-05-31T14:33:33+00:00

After registering the task free notifier we possibly have tasks in our
dying_tasks list. Free them after unregistering the notifier in case
of an error.

Cc:  # .36+
Signed-off-by: Robert Richter

oprofile: Remove deprecated use of flush_scheduled_work()

2010-10-29T09:54:18+00:00

flush_scheduled_work() is deprecated and scheduled to be removed.
sync_stop() currently cancels cpu_buffer works inside buffer_mutex and
flushes the system workqueue outside.  Instead, split end_cpu_work()
into two parts - stopping further work enqueues and flushing works -
and do the former inside buffer_mutex and latter outside.

For stable kernels v2.6.35.y and v2.6.36.y.

Signed-off-by: Tejun Heo 
Cc: stable@kernel.org
Signed-off-by: Robert Richter

oprofile: fix crash when accessing freed task structs

2010-08-25T07:09:09+00:00

This patch fixes a crash during shutdown reported below. The crash is
caused by accessing already freed task structs. The fix changes the
order for registering and unregistering notifier callbacks.

All notifiers must be initialized before buffers start working. To
stop buffer synchronization we cancel all workqueues, unregister the
notifier callback and then flush all buffers. After all of this we
finally can free all tasks listed.

This should avoid accessing freed tasks.

On 22.07.10 01:14:40, Benjamin Herrenschmidt wrote:

> So the initial observation is a spinlock bad magic followed by a crash
> in the spinlock debug code:
>
> [ 1541.586531] BUG: spinlock bad magic on CPU#5, events/5/136
> [ 1541.597564] Unable to handle kernel paging request for data at address 0x6b6b6b6b6b6b6d03
>
> Backtrace looks like:
>
>       spin_bug+0x74/0xd4
>       ._raw_spin_lock+0x48/0x184
>       ._spin_lock+0x10/0x24
>       .get_task_mm+0x28/0x8c
>       .sync_buffer+0x1b4/0x598
>       .wq_sync_buffer+0xa0/0xdc
>       .worker_thread+0x1d8/0x2a8
>       .kthread+0xa8/0xb4
>       .kernel_thread+0x54/0x70
>
> So we are accessing a freed task struct in the work queue when
> processing the samples.

Reported-by: Benjamin Herrenschmidt 
Cc: stable@kernel.org
Signed-off-by: Robert Richter

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

2010-03-30T13:02:32+00:00

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

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

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

The script does the followings.

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

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

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

The conversion was done in the following steps.

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

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

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

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

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

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

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

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

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

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

cpumask: use zalloc_cpumask_var() where possible

2009-09-24T00:04:24+00:00

Remove open-coded zalloc_cpumask_var() and zalloc_cpumask_var_node().

Signed-off-by: Li Zefan 
Signed-off-by: Rusty Russell

cpumask: modifiy oprofile initialization

2009-01-22T13:37:06+00:00

Delta patch to f7df8ed164996cd2c6aca9674388be6ef78d8b37 for
tip/cpus4096.

Moved initialization to sync_start()/sync_stop(). No changes needed in
buffer_sync.h and oprof.c anymore.

Signed-off-by: Robert Richter 
Signed-off-by: Ingo Molnar

cpumask: convert misc driver functions

2009-01-11T18:12:52+00:00

Impact: use new cpumask API.

Convert misc driver functions to use struct cpumask.

To Do:
  - Convert iucv_buffer_cpumask to cpumask_var_t.

Signed-off-by: Rusty Russell 
Signed-off-by: Mike Travis 
Acked-by: Dean Nelson 
Cc: Robert Richter 
Cc: oprofile-list@lists.sf.net
Cc: Jeremy Fitzhardinge 
Cc: Chris Wright 
Cc: virtualization@lists.osdl.org
Cc: xen-devel@lists.xensource.com
Cc: Ursula Braun 
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile

2009-01-09T20:43:06+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile: (31 commits)
  powerpc/oprofile: fix whitespaces in op_model_cell.c
  powerpc/oprofile: IBM CELL: add SPU event profiling support
  powerpc/oprofile: fix cell/pr_util.h
  powerpc/oprofile: IBM CELL: cleanup and restructuring
  oprofile: make new cpu buffer functions part of the api
  oprofile: remove #ifdef CONFIG_OPROFILE_IBS in non-ibs code
  ring_buffer: fix ring_buffer_event_length()
  oprofile: use new data sample format for ibs
  oprofile: add op_cpu_buffer_get_data()
  oprofile: add op_cpu_buffer_add_data()
  oprofile: rework implementation of cpu buffer events
  oprofile: modify op_cpu_buffer_read_entry()
  oprofile: add op_cpu_buffer_write_reserve()
  oprofile: rename variables in add_ibs_begin()
  oprofile: rename add_sample() in cpu_buffer.c
  oprofile: rename variable ibs_allowed to has_ibs in op_model_amd.c
  oprofile: making add_sample_entry() inline
  oprofile: remove backtrace code for ibs
  oprofile: remove unused ibs macro
  oprofile: remove unused components in struct oprofile_cpu_buffer
  ...