pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig()
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From: Serge E. Hallyn on 4 Mar 2010 02:30 Quoting Oleg Nesterov (oleg(a)redhat.com): > zap_pid_ns_processes() uses force_sig(SIGKILL) to ensure SIGKILL > will be delivered to sub-namespace inits as well. This is correct, > but we are going to change force_sig_info() semantics. > See http://bugzilla.kernel.org/show_bug.cgi?id=15395#c31 > > We can use send_sig_info(SEND_SIG_NOINFO) instead, since > 614c517d7c00af1b26ded20646b329397d6f51a1 SEND_SIG_NOINFO means > "from user" and therefore send_signal() will get the correct > from_ancestor_ns = T flag. > > Signed-off-by: Oleg Nesterov <oleg(a)redhat.com> Justification makes sense, and (in some superficial testing, killing some nested pid_ns's) the patch seems to do the right thing. Acked-by: Serge Hallyn <serue(a)us.ibm.com> > --- > > kernel/pid_namespace.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > --- mm/kernel/pid_namespace.c~NS_DONT_ABUSE_FORCE 2010-02-25 15:22:13.000000000 +0100 > +++ mm/kernel/pid_namespace.c 2010-03-03 20:58:12.000000000 +0100 > @@ -161,13 +161,12 @@ void zap_pid_ns_processes(struct pid_nam > rcu_read_lock(); > > /* > - * Use force_sig() since it clears SIGNAL_UNKILLABLE ensuring > - * any nested-container's init processes don't ignore the > - * signal > + * Any nested-container's init processes won't ignore the > + * SEND_SIG_NOINFO signal, see send_signal()->si_fromuser(). > */ > task = pid_task(find_vpid(nr), PIDTYPE_PID); > if (task) > - force_sig(SIGKILL, task); > + send_sig_info(SIGKILL, SEND_SIG_NOINFO, task); > > rcu_read_unlock(); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |