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Date: Sun, 11 Jan 2009 07:15:05 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: ebiederm@xmission.com, roland@redhat.com, bastian@waldi.eu.org,
       containers@lists.osdl.org, linux-kernel@vger.kernel.org,
       xemul@openvz.org
Subject: Re: [PATCH 6/7][v6] Protect cinit from blocked fatal signals
Message-ID: <20090111061505.GB9014@redhat.com>
References: <20090107074558.GA27881@us.ibm.com> <20090107075214.GF27985@us.ibm.com>
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On 01/06, Sukadev Bhattiprolu wrote:
>
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -1890,9 +1890,16 @@ relock:
>
>  		/*
>  		 * Global init gets no signals it doesn't want.
> +		 * Container-init gets no signals it doesn't want from same
> +		 * container.
> +		 *
> +		 * Note that if global/container-init sees a sig_kernel_only()
> +		 * signal here, the signal must have been generated internally
> +		 * or must have come from an ancestor namespace. In either
> +		 * case, the signal cannot be dropped.
>  		 */
>  		if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
> -		    !signal_group_exit(signal))
> +				!sig_kernel_only(signr))

Just for record. We still have small problem with fatal_signal_pending(cinit),
we should add a similar change to complete_signal to ensure that the pending
SIGKILL implies SIGNAL_GROUP_EXIT. But this needs another patch, and this
series is imho fine.

Oleg.