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    Subject[patch 079/114] copy_process: fix CLONE_PARENT && parent_exec_id interaction
    2.6.28-stable review patch.  If anyone has any objections, please let us know.

    ------------------

    From: Oleg Nesterov <oleg@redhat.com>

    commit 2d5516cbb9daf7d0e342a2e3b0fc6f8c39a81205 upstream.

    CLONE_PARENT can fool the ->self_exec_id/parent_exec_id logic. If we
    re-use the old parent, we must also re-use ->parent_exec_id to make
    sure exit_notify() sees the right ->xxx_exec_id's when the CLONE_PARENT'ed
    task exits.

    Also, move down the "p->parent_exec_id = p->self_exec_id" thing, to place
    two different cases together.

    Signed-off-by: Oleg Nesterov <oleg@redhat.com>
    Cc: Roland McGrath <roland@redhat.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: David Howells <dhowells@redhat.com>
    Cc: Serge E. Hallyn <serge@hallyn.com>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    kernel/fork.c | 11 +++++------
    1 file changed, 5 insertions(+), 6 deletions(-)

    --- a/kernel/fork.c
    +++ b/kernel/fork.c
    @@ -1176,10 +1176,6 @@ static struct task_struct *copy_process(
    #endif
    clear_all_latency_tracing(p);

    - /* Our parent execution domain becomes current domain
    - These must match for thread signalling to apply */
    - p->parent_exec_id = p->self_exec_id;
    -
    /* ok, now we should be set up.. */
    p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
    p->pdeath_signal = 0;
    @@ -1217,10 +1213,13 @@ static struct task_struct *copy_process(
    set_task_cpu(p, smp_processor_id());

    /* CLONE_PARENT re-uses the old parent */
    - if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
    + if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
    p->real_parent = current->real_parent;
    - else
    + p->parent_exec_id = current->parent_exec_id;
    + } else {
    p->real_parent = current;
    + p->parent_exec_id = current->self_exec_id;
    + }

    spin_lock(&current->sighand->siglock);




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