1. 09 Jun, 2008 1 commit
  2. 29 May, 2008 1 commit
    • Lothar Waßmann's avatar
      [CPUFREQ] fix double unlock of cpu_policy_rwsem in drivers/cpufreq/cpufreq.c · dca02613
      Lothar Waßmann authored
      In drivers/cpufreq/cpufreq.c the function cpufreq_add_dev() takes the
      error exit 'err_out_unregister' from different places once with the
      'cpu_policy_rwsem' lock held, once with the lock released:
      |		if (ret)
      |			goto err_out_unregister;
      |	}
      |
      |	policy->governor = NULL; /* to assure that the starting sequence is
      |				  * run in cpufreq_set_policy */
      |
      |	/* set default policy */
      |	ret = __cpufreq_set_policy(policy, &new_policy);
      |	policy->user_policy.policy = policy->policy;
      |	policy->user_policy.governor = policy->governor;
      |
      |	unlock_policy_rwsem_write(cpu);
      |
      |	if (ret) {
      |		dprintk("setting policy failed\n");
      |		goto err_out_unregister;
      |	}
      
      This leads to the following error message in case of a failing
      __cpufreq_set_policy() call:
      =====================================
      [ BUG: bad unlock balance detected! ]
      -------------------------------------
      swapper/1 is trying to release lock (&per_cpu(cpu_policy_rwsem, cpu)) at:
      [<c01b4564>] unlock_policy_rwsem_write+0x30/0x40
      but there are no more locks to release!
      
      other info that might help us debug this:
      1 lock held by swapper/1:
       #0:  (sysdev_drivers_lock){--..}, at: [<c018fd18>] sysdev_driver_register+0x74/0x130
      
      stack backtrace:
      [<c002f588>] (dump_stack+0x0/0x14) from [<c00692fc>] (print_unlock_inbalance_bug+0xc8/0x104)
      [<c0069234>] (print_unlock_inbalance_bug+0x0/0x104) from [<c006b7ac>] (lock_release_non_nested+0xc4/0x19c)
       r6:00000028 r5:c3c1ab80 r4:c01b4564
      [<c006b6e8>] (lock_release_non_nested+0x0/0x19c) from [<c006b9e0>] (lock_release+0x15c/0x18c)
       r8:60000013 r7:00000001 r6:c01b4564 r5:c0541bb4 r4:c3c1ab80
      [<c006b884>] (lock_release+0x0/0x18c) from [<c0061ba0>] (up_write+0x24/0x30)
       r8:c0541b80 r7:00000000 r6:ffffffea r5:c3c34828 r4:c0541b8c
      [<c0061b7c>] (up_write+0x0/0x30) from [<c01b4564>] (unlock_policy_rwsem_write+0x30/0x40)
       r4:c3c34884
      [<c01b4534>] (unlock_policy_rwsem_write+0x0/0x40) from [<c01b4c40>] (cpufreq_add_dev+0x324/0x398)
      [<c01b491c>] (cpufreq_add_dev+0x0/0x398) from [<c018fd64>] (sysdev_driver_register+0xc0/0x130)
      [<c018fca4>] (sysdev_driver_register+0x0/0x130) from [<c01b3574>] (cpufreq_register_driver+0xbc/0x174)
      Signed-off-by: default avatarLothar Waßmann <LW@KARO-electronics.de>
      Signed-off-by: default avatarDave Jones <davej@redhat.com>
      dca02613
  3. 22 May, 2008 1 commit
  4. 21 May, 2008 1 commit
  5. 19 May, 2008 13 commits
  6. 18 May, 2008 23 commits