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    SubjectRe: RT Mutex patch and tester [PREEMPT_RT]
    On Wed, Jan 11, 2006 at 06:25:36PM +0100, Esben Nielsen wrote:
    > So how many locks do we have to worry about? Two.
    > One for locking the lock. One for locking various PI related data on the
    > task structure, as the pi_waiters list, blocked_on, pending_owner - and
    > also prio.
    > Therefore only lock->wait_lock and sometask->pi_lock will be locked at the
    > same time. And in that order. There is therefore no spinlock deadlocks.
    > And the code is simpler.

    Ok, got a question. How do deal with the false reporting and handling of
    a lock circularity window involving the handoff of task A's BKL to another
    task B ? Task A is blocked trying to get a mutex owned by task B, task A
    is block B since it owns BKL which task B is contending on. It's not a
    deadlock since it's a hand off situation.

    I didn't see any handling of this case in the code and I was wondering
    if the traversal logic you wrote avoids this case as an inherent property
    and I missed that stuff ?


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      Last update: 2006-01-15 05:30    [W:0.029 / U:3.428 seconds]
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