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Bug #635

closed

Add mutex_is_locked() to model of rule#32

Added by Alexey Khoroshilov almost 14 years ago. Updated almost 14 years ago.

Status:
Closed
Priority:
High
Assignee:
Category:
Rules and Models
Start date:
12/21/2010
Due date:
% Done:

0%

Estimated time:
Detected in build:
588b549
Platform:
Published in build:
4b63f97716aff56612b5252b9409b96c78846bfe

Description

Lack of the mutex_is_locked() in our model leads to false positives.

/**
 * mutex_is_locked - is the mutex locked
 * @lock: the mutex to be queried
 *
 * Returns 1 if the mutex is locked, 0 if unlocked.
 */
static inline int mutex_is_locked(struct mutex *lock)
{
        return atomic_read(&lock->count) != 1;
}

Files

mutexislocked.c (978 Bytes) mutexislocked.c Broken regression test file Evgeny Novikov, 01/29/2011 12:49 PM
Actions #1

Updated by Alexey Khoroshilov almost 14 years ago

Drivers where false positive appears (linus-tree):
cx23885-vbi.ko
saa7134-video.ko

Actions #2

Updated by Vadim Mutilin almost 14 years ago

What model do you use? 32_7?
Is it ldv-git?
Also an error trace would be preferable (link to loaded stats or file) or description of called functions and lines in files where it occurs.

Actions #3

Updated by Pavel Shved almost 14 years ago

Вадим Мутилин wrote:

What model do you use? 32_7?
Is it ldv-git?
Also an error trace would be preferable (link to loaded stats or file) or description of called functions and lines in files where it occurs.

Perhaps, writing a couple of small drivers manually would be enough to test if your fix works? It would be a nice thing to do anyway.

Actions #4

Updated by Vadim Mutilin almost 14 years ago

It would be a nice thing but possibly not enough because false positive may be more malicious

Actions #5

Updated by Alexey Khoroshilov almost 14 years ago

Вадим Мутилин wrote:

What model do you use? 32_7?
Is it ldv-git?
Also an error trace would be preferable (link to loaded stats or file) or description of called functions and lines in files where it occurs.

32_7, ldv-git

ldv_initialize_FOREACH
IN_INTERRUPT = 1;
vbi_setup
vbi_prepare
vbi_queue
vbi_release
  cx23885_free_buffer
    videobuf_waiton(q /* q */, buf vb /* vb */, 0 /* non_blocking */, 0 /* intr */);
    {
      ret = 0;
      assert(* (vb ).magic == 537331496);
      __cil_tmp22 = 0;
      tmp___7 = __builtin_expect(__cil_tmp22 /* val */, 0 /* res */);
      {
        return val;
      }
      assert(tmp___7 == 0);
      assert(non_blocking == 0);
      assert(* (q ).ext_lock != 0);
      tmp___9 = mutex_is_locked(* (q ).ext_lock /* lock */);
      {
        tmp = atomic_read(lock foffset count /* v */);
        {
          mem_2 = v foffset counter;
          __retres3 = * (mem_2 );
          return __retres3;
        }
        assert(tmp != 1);
        __cil_tmp3 = 1;
        return __cil_tmp3;
      }
      assert(tmp___9 != 0);
      tmp___10 = 1;
      is_ext_locked = tmp___10;
      assert(is_ext_locked != 0);
      mutex_unlock_ext_lock(* (q ).ext_lock /* lock */);
      {
        assert(ldv_mutex_ext_lock != 2);
        __blast_assert();
Actions #6

Updated by Vadim Mutilin almost 14 years ago

rule model 32_7

module cx23885-vbi.ko ldv_main0_plain_sorted_withcheck
Main generated for file cx23885-vbi.c
callback vbi_release->cx23885_free_buffer(cx23885-core.c)->videobuf_waiton(videobuf-core.c line 102)

module saa7134-video.ko ldv_main0_plain_sorted_withcheck
Main generated for saa7134-video.c
callback buffer_prepare->saa7134_dma_free->videobuf_waiton(videobuf-core.c line 102)

Actions #7

Updated by Vadim Mutilin almost 14 years ago

  • Status changed from New to Feedback
  • Published in build set to c47eb81

fixed in c47eb81
tested on ldv-tests/regr-tests/test-sets/small/drivers/tests-model-32_7/test-mutexislocked/mutexislocked.c

Actions #8

Updated by Pavel Shved almost 14 years ago

  • Status changed from Feedback to Resolved

Maybe it should be closed now?

Actions #9

Updated by Alexey Khoroshilov almost 14 years ago

  • Status changed from Resolved to Closed
Actions #10

Updated by Alexey Khoroshilov almost 14 years ago

  • Status changed from Closed to Open

К сожалению, обнаружилось, что почему-то mutex_is_locked не работает. См. например:

ldv-git --force --keep-work --rule=32_7 --filter=media/video/bt8xx/bttv-vbi check

Actions #11

Updated by Vadim Mutilin almost 14 years ago

I forgot to update rerouting options. Fixed it in d1a476a

Actions #12

Updated by Evgeny Novikov almost 14 years ago

Nowadays mutex_is_locked becomes completely broken! Even small regression test says it (see attachment).
Don't forget to update small regression test set after bug fixing!!!

Actions #13

Updated by Vadim Mutilin almost 14 years ago

Small tests fixed to find both errors old and new.
New error is fixed in 4b63f97716aff56612b5252b9409b96c78846bfe
(bug #754 in rerouting is found, which does not prevent fixing this bug)

Actions #14

Updated by Evgeny Novikov almost 14 years ago

Should this bug be closed after all?

Actions #15

Updated by Vadim Mutilin almost 14 years ago

test with ldv-git didn't finished yet

Actions #16

Updated by Vadim Mutilin almost 14 years ago

  • Status changed from Open to Resolved
  • Published in build changed from c47eb81 to 4b63f97716aff56612b5252b9409b96c78846bfe

bttv-vbi.ko is safe now

Actions #18

Updated by Vadim Mutilin almost 14 years ago

Looks like kernel-rules submodule is not updated in your repository.
File bttv-vbi.c.common.c contains the old model.

Actions #19

Updated by Alexey Khoroshilov almost 14 years ago

  • Status changed from Open to Closed

Sorry, I have looked in a wrong tab. It was a result of the previous run.

bttv-vbi.c is UNKNOWN now, but other issues of this kind are fixed.

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