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From: Richard Guy Briggs <rgb@redhat.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	linux-audit@redhat.com, Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [RFC PATCH v3] audit: use proper refcount locking on audit_sock
Date: Tue, 13 Dec 2016 23:00:05 -0500	[thread overview]
Message-ID: <20161214040005.GL22660@madcap2.tricolour.ca> (raw)
In-Reply-To: <CAM_iQpVFkNdEirvBDi8wV=iExt9BnCm3KU7+Q8oqhrJJtcnu9Q@mail.gmail.com>

On 2016-12-13 16:19, Cong Wang wrote:
> On Tue, Dec 13, 2016 at 7:03 AM, Richard Guy Briggs <rgb@redhat.com> wrote:
> > @@ -1283,8 +1299,10 @@ static void __net_exit audit_net_exit(struct net *net)
> >  {
> >         struct audit_net *aunet = net_generic(net, audit_net_id);
> >         struct sock *sock = aunet->nlsk;
> > +       mutex_lock(&audit_cmd_mutex);
> >         if (sock == audit_sock)
> >                 auditd_reset();
> > +       mutex_unlock(&audit_cmd_mutex);
> 
> This still doesn't look correct to me, b/c here we release the audit_sock
> refcnt twice:
> 
> 1) inside audit_reset()

The audit_reset() refcount decrement corresponds to a setting of
audit_sock only if audit_sock is still non-NULL.

> 2) netlink_kernel_release()

This refcount decrement corresponds to netlink_kernel_create().

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Kernel Security Engineering, Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635

  reply	other threads:[~2016-12-14  4:00 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CACT4Y+aG1+91U1PWMTwpE_6vbEuqG7CdLCM1H=3WVJWtz=>
     [not found] ` <CAM_iQpVeLvfYV+1jX1ZKOntZim4roof4=>
2016-11-29 16:48   ` netlink: GPF in sock_sndtimeo Richard Guy Briggs
2016-11-29 23:13     ` Cong Wang
2016-11-30  4:52       ` Richard Guy Briggs
2016-12-09  6:02         ` Richard Guy Briggs
2016-12-09  6:57           ` Cong Wang
2016-12-09 11:01             ` Richard Guy Briggs
2016-12-10  4:13               ` Cong Wang
2016-12-10  7:40                 ` Cong Wang
2016-12-12 10:07                   ` Dmitry Vyukov
2016-12-13  7:51                   ` Richard Guy Briggs
2016-12-13  8:28                     ` Richard Guy Briggs
2016-12-12 10:02                 ` Richard Guy Briggs
2016-12-12 10:03                   ` [PATCH v2] audit: use proper refcount locking on audit_sock Richard Guy Briggs
2016-12-12 17:10                     ` Paul Moore
2016-12-13  4:49                       ` Richard Guy Briggs
2016-12-12 20:18                     ` Paul Moore
2016-12-13  5:10                       ` Richard Guy Briggs
2016-12-13 15:01                         ` Richard Guy Briggs
2016-12-12 23:58                     ` Cong Wang
2016-12-13 14:55                       ` Richard Guy Briggs
2016-12-13  0:10                   ` netlink: GPF in sock_sndtimeo Cong Wang
2016-12-13 10:52                     ` Richard Guy Briggs
2016-12-14  0:17                       ` Cong Wang
2016-12-14  4:17                         ` Richard Guy Briggs
2016-12-13 15:03                   ` [RFC PATCH v3] audit: use proper refcount locking on audit_sock Richard Guy Briggs
2016-12-13 20:50                     ` Paul Moore
2016-12-14  0:19                     ` Cong Wang
2016-12-14  4:00                       ` Richard Guy Briggs [this message]
2016-12-14  5:36                         ` Cong Wang
2016-12-09 10:49           ` netlink: GPF in sock_sndtimeo Dmitry Vyukov
2016-12-09 11:48             ` Richard Guy Briggs
2016-12-09 11:53               ` Dmitry Vyukov
2016-12-09 12:12                 ` Richard Guy Briggs

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