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 <bhubb...@redhat.com> Signed-off-by: Michael S. Tsirkin <m...@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]);
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/