On 07/09/2013 06:35 PM, Michael S. Tsirkin wrote: > On Tue, Jul 09, 2013 at 06:10:51PM +0800, Jason Wang wrote: >> Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to >> linearize parts of the skb to let the rest of iov to be fit in >> the frags, we need count copylen into linear when calling macvtap_alloc_skb() >> instead of partly counting it into data_len. Since this breaks >> zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should >> be zero at beginning. This cause nr_frags to be increased wrongly without >> setting the correct frags. >> >> This bug were introduced from b92946e2919134ebe2a4083e4302236295ea2a73 >> (macvtap: zerocopy: validate vectors before building skb). >> >> Cc: Michael S. Tsirkin <[email protected]> >> Signed-off-by: Jason Wang <[email protected]> >> --- >> This patch is needed for stable. >> --- >> drivers/net/macvtap.c | 3 ++- >> 1 files changed, 2 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c >> index f2c4a3b..b213020 100644 >> --- a/drivers/net/macvtap.c >> +++ b/drivers/net/macvtap.c >> @@ -770,7 +770,8 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, >> struct msghdr *m, >> copylen = len; >> >> skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, >> - vnet_hdr.hdr_len, noblock, &err); >> + zerocopy ? copylen : vnet_hdr.hdr_len, >> + noblock, &err); >> if (!skb) >> goto err; > Same comment as for tun - let's add code for the if statement above. > Thanks! >
Sure, I will post v2. Thanks >> -- >> 1.7.1 > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
