From 7e24bfbe43b545b1689a5f134ed83645b9e34b86 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 23 Jun 2013 17:19:03 +0300 Subject: [PATCH] tun: fix recovery from gup errors 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 Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Acked-by: Neil Horman Signed-off-by: David S. Miller --- drivers/net/tun.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index bfa9bb48e42d..9c61f8734a40 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1010,8 +1010,10 @@ 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;