* Re: [PATCH] pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig()
2010-03-03 20:26 ` [PATCH] pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig() Oleg Nesterov
@ 2010-03-04 7:20 ` Serge E. Hallyn
2010-03-04 16:06 ` Linus Torvalds
2010-03-04 20:48 ` Roland McGrath
2 siblings, 0 replies; 4+ messages in thread
From: Serge E. Hallyn @ 2010-03-04 7:20 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Andrew Morton, Roland McGrath, wylda, gregkh, jkosina,
Linus Torvalds, Sukadev Bhattiprolu, linux-kernel
Quoting Oleg Nesterov (oleg@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@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@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();
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig()
2010-03-03 20:26 ` [PATCH] pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig() Oleg Nesterov
2010-03-04 7:20 ` Serge E. Hallyn
@ 2010-03-04 16:06 ` Linus Torvalds
2010-03-04 20:48 ` Roland McGrath
2 siblings, 0 replies; 4+ messages in thread
From: Linus Torvalds @ 2010-03-04 16:06 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Andrew Morton, Roland McGrath, wylda, gregkh, jkosina,
Sukadev Bhattiprolu, Serge Hallyn, linux-kernel
On Wed, 3 Mar 2010, Oleg Nesterov wrote:
>
> 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@redhat.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig()
2010-03-03 20:26 ` [PATCH] pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig() Oleg Nesterov
2010-03-04 7:20 ` Serge E. Hallyn
2010-03-04 16:06 ` Linus Torvalds
@ 2010-03-04 20:48 ` Roland McGrath
2 siblings, 0 replies; 4+ messages in thread
From: Roland McGrath @ 2010-03-04 20:48 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Andrew Morton, wylda, gregkh, jkosina, Linus Torvalds,
Sukadev Bhattiprolu, Serge Hallyn, linux-kernel
Acked-by: Roland McGrath <roland@redhat.com>
^ permalink raw reply [flat|nested] 4+ messages in thread