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,
daniel@hozac.com, xemul@openvz.org, containers@lists.osdl.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/6][v5] Define siginfo_from_ancestor_ns()
Date: Mon, 5 Jan 2009 15:33:34 +0100 [thread overview]
Message-ID: <20090105143334.GD3313@redhat.com> (raw)
In-Reply-To: <20081227205222.GB27337@us.ibm.com>
Really minor nit, just noticed...
On 12/27, Sukadev Bhattiprolu wrote:
>
> +static inline int siginfo_from_ancestor_ns(struct task_struct *t,
> + siginfo_t *info)
> +{
> + struct pid_namespace *ns;
> +
> + /*
> + * Ensure signal is from user-space before checking pid namespace.
> + * (We maybe called from interrupt context and dereferencing
> + * pid namespace would be safe).
> + */
> + if (siginfo_from_user(info)) {
I can't parse the comment above, and imho it is confusing and
misleading. We can dereference pid namespace even in interrupt
context.
Also, the comment looks as if "when siginfo_from_user() is false,
it is not safe/possible to derive from_ancestor_ns". This is not
true, in that case we know that from_ancestor_ns must be false.
from_ancestor_ns == T means the signal was sent from the user
space, and it was sent to the task in the sub-namespace, so it
is clear why we check siginfo_from_user().
Oleg.
next prev parent reply other threads:[~2009-01-05 14:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-27 20:46 [PATCH 0/6][v5]: Container-init signal semantics Sukadev Bhattiprolu
2008-12-27 20:49 ` [PATCH 1/6][v5] Remove 'handler' parameter to tracehook functions Sukadev Bhattiprolu
2008-12-27 20:51 ` [PATCH 2/6][v5] Protect init from unwanted signals more Sukadev Bhattiprolu
2008-12-27 20:52 ` [PATCH 3/6][v5] Define siginfo_from_ancestor_ns() Sukadev Bhattiprolu
2008-12-31 0:12 ` Roland McGrath
2009-01-05 12:42 ` Oleg Nesterov
2009-01-05 14:33 ` Oleg Nesterov [this message]
2008-12-27 20:53 ` [PATCH 4/6][v5] Protect cinit from unblocked SIG_DFL signals Sukadev Bhattiprolu
2008-12-31 0:19 ` Roland McGrath
2009-01-05 13:24 ` Oleg Nesterov
2008-12-27 20:54 ` [PATCH 5/6][v5] Protect cinit from blocked fatal signals Sukadev Bhattiprolu
2009-01-05 15:16 ` Oleg Nesterov
2008-12-27 20:55 ` [PATCH 6/6][v5] SI_USER: Masquerade si_pid when crossing pid ns boundary Sukadev Bhattiprolu
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