Commit 13aa9a6b authored Mar 10, 2010 by Oleg Nesterov Committed by Linus Torvalds Mar 12, 2010

pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig()

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
614c517d ("signals: SEND_SIG_NOINFO should
be considered as SI_FROMUSER()") 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@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 6edb6764

kernel/pid_namespace.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -161,13 +161,12 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
		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();

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