From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Jakub Kicinski <kubakici@wp.pl>,
davem@davemloft.net, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 3/3] tap: XDP support
Date: Fri, 28 Jul 2017 06:46:40 +0300 [thread overview]
Message-ID: <20170728064603-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <7d1cb7bf-43c1-3993-be00-04e4676dd917@redhat.com>
On Fri, Jul 28, 2017 at 11:28:54AM +0800, Jason Wang wrote:
> > > + old_prog = rtnl_dereference(tun->xdp_prog);
> > > + if (old_prog)
> > > + bpf_prog_put(old_prog);
> > > + rcu_assign_pointer(tun->xdp_prog, prog);
> > Is this OK? Could this lead to the program getting freed and then
> > datapath accessing a stale pointer? I mean in the scenario where the
> > process gets pre-empted between the bpf_prog_put() and
> > rcu_assign_pointer()?
>
> Will call bpf_prog_put() after rcu_assign_pointer().
I suspect you need to sync RCU or something before that.
next prev parent reply other threads:[~2017-07-28 3:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-27 9:25 [PATCH net-next 0/3] XDP support for tap Jason Wang
2017-07-27 9:25 ` [PATCH net-next 1/3] tap: use build_skb() for small packet Jason Wang
2017-07-27 9:25 ` [PATCH net-next 2/3] net: export some generic xdp helpers Jason Wang
2017-07-27 9:25 ` [PATCH net-next 3/3] tap: XDP support Jason Wang
2017-07-28 3:13 ` Jakub Kicinski
2017-07-28 3:28 ` Jason Wang
2017-07-28 3:46 ` Michael S. Tsirkin [this message]
2017-07-28 3:50 ` Jason Wang
2017-07-28 4:05 ` Michael S. Tsirkin
2017-07-28 3:51 ` Jakub Kicinski
2017-07-28 15:11 ` Daniel Borkmann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170728064603-mutt-send-email-mst@kernel.org \
--to=mst@redhat.com \
--cc=davem@davemloft.net \
--cc=jasowang@redhat.com \
--cc=kubakici@wp.pl \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.