lkml.org 
[lkml]   [2013]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 044/106] macvtap: fix recovery from gup errors
    Date
    3.5.7.18 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: "Michael S. Tsirkin" <mst@redhat.com>

    commit 4c7ab054ab4f5d63625508ed6f8a607184cae7c2 upstream.

    get user pages might fail partially in macvtap 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>
    Acked-by: Jason Wang <jasowang@redhat.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    ---
    drivers/net/macvtap.c | 6 ++++--
    1 file changed, 4 insertions(+), 2 deletions(-)

    diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
    index 2ee56de..d566234 100644
    --- a/drivers/net/macvtap.c
    +++ b/drivers/net/macvtap.c
    @@ -534,8 +534,10 @@ 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;
    +
    + for (j = 0; j < num_pages; j++)
    + put_page(page[i + j]);
    return -EFAULT;
    }
    truesize = size * PAGE_SIZE;
    --
    1.8.3.2


    \
     
     \ /
      Last update: 2013-07-30 12:01    [W:8.103 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site