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    SubjectRe: [PATCH 1/1] ptrace: do_wait(traced_leader_killed_by_mt_exec) can block forever
    Hello,

    On Thu, Jul 21, 2011 at 08:00:43PM +0200, Oleg Nesterov wrote:
    > It is racy, exit_notify() does __wake_up_parent() too. But in the
    > likely case it triggers the problem: de_thread() does release_task()
    > and the old leader goes away without the notification, the tracer
    > sleeps in do_wait() without children/tracees.
    >
    > Change de_thread() to do __wake_up_parent(traced_leader->parent).
    > Since it is already EXIT_DEAD we can do this without ptrace_unlink(),
    > EXIT_DEAD threads do not exist from do_wait's pov.
    >
    > Signed-off-by: Oleg Nesterov <oleg@redhat.com>

    Nice catch as always. :)

    Acked-by: Tejun Heo <tj@kernel.org>

    Thanks.

    --
    tejun


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