From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Jason Wang <jasowang@redhat.com>,
Eric Dumazet <edumazet@google.com>,
Neil Horman <nhorman@tuxdriver.com>,
netdev@vger.kernel.org, Brad Hubbard <bhubbard@redhat.com>
Subject: Re: [PATCH net] tun: fix recovery from gup errors
Date: Sun, 23 Jun 2013 19:36:21 +0400 [thread overview]
Message-ID: <51C715F5.2050300@cogentembedded.com> (raw)
In-Reply-To: <20130623141903.GA21029@redhat.com>
Hello.
On 23-06-2013 18:19, Michael S. Tsirkin wrote:
> get user pages might fail partially in tun zero copy
> mode. To recover we need to put all pages that we got,
> but code used a wrong index resulting in double-free
> errors.
> Reported-by: Brad Hubbard <bhubbard@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> I haven't figured out why do we get failures,
> but recovery is clearly wrong.
> This is also -stable material.
> drivers/net/tun.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index bfa9bb4..c098b1e 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1010,8 +1010,9 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
> return -EMSGSIZE;
> num_pages = get_user_pages_fast(base, size, 0, &page[i]);
> if (num_pages != size) {
> - for (i = 0; i < num_pages; i++)
> - put_page(page[i]);
> + int j;
Empty line wouldn't hurt here, after declaration.
> + for (j = 0; j < num_pages; j++)
> + put_page(page[i + j]);
next prev parent reply other threads:[~2013-06-23 15:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-23 14:19 [PATCH net] tun: fix recovery from gup errors Michael S. Tsirkin
2013-06-23 15:36 ` Sergei Shtylyov [this message]
2013-06-24 12:54 ` Michael S. Tsirkin
2013-06-24 18:34 ` David Miller
2013-06-24 3:22 ` Jason Wang
2013-06-25 23:24 ` David Miller
2013-06-24 11:31 ` Neil Horman
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