lkml.org 
[lkml]   [2012]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH 1/1] CLONE_PARENT shouldn't allow to set ->exit_signal
    The child must not control its ->exit_signal, it is the parent who
    decides which signal the child should use for notification.

    This means that CLONE_PARENT should not use "clone_flags & CSIGNAL",
    the forking task is the sibling of the new process and their parent
    doesn't control exit_signal in this case.

    This patch uses ->exit_signal of the forking process, but perhaps
    we should simply use SIGCHLD.

    We read group_leader->exit_signal lockless, this can race with the
    ORIGINAL_SIGNAL -> SIGCHLD transition, but this is fine.

    Potentially this change allows to kill self_exec_id/parent_exec_id.

    Signed-off-by: Oleg Nesterov <oleg@redhat.com>
    ---
    kernel/fork.c | 8 +++++++-
    1 files changed, 7 insertions(+), 1 deletions(-)

    diff --git a/kernel/fork.c b/kernel/fork.c
    index b77fd55..34d7ed1 100644
    --- a/kernel/fork.c
    +++ b/kernel/fork.c
    @@ -1310,7 +1310,13 @@ static struct task_struct *copy_process(unsigned long clone_flags,
    clear_all_latency_tracing(p);

    /* ok, now we should be set up.. */
    - p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
    + if (clone_flags & CLONE_THREAD)
    + p->exit_signal = -1;
    + else if (clone_flags & CLONE_PARENT)
    + p->exit_signal = current->group_leader->exit_signal;
    + else
    + p->exit_signal = (clone_flags & CSIGNAL);
    +
    p->pdeath_signal = 0;
    p->exit_state = 0;

    --
    1.5.5.1



    \
     
     \ /
      Last update: 2012-03-14 20:59    [W:0.020 / U:32.432 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site