Messages in this thread | | | Date | Sun, 23 Jun 2013 19:36:21 +0400 | From | Sergei Shtylyov <> | Subject | Re: [PATCH net] tun: fix recovery from gup errors |
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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]);
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