blob: 95ec2985029a4a158200d55f8656bf80288ea94a [file] [log] [blame]
From b716ef2d9113847c893a292d9624a53b8b0d472f Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Sun, 23 Jun 2013 17:26:58 +0300
Subject: macvtap: fix recovery from gup errors
From: "Michael S. Tsirkin" <mst@redhat.com>
[ Upstream commit 4c7ab054ab4f5d63625508ed6f8a607184cae7c2 ]
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/macvtap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -534,8 +534,10 @@ static int zerocopy_sg_from_iovec(struct
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]);
}
truesize = size * PAGE_SIZE;
skb->data_len += len;