On Thu, Dec 22, 2016 at 04:12:13PM -0800, Andrey Vagin wrote: > On Thu, Dec 22, 2016 at 03:34:15PM -0800, Andrey Vagin wrote: > > On Thu, Dec 22, 2016 at 06:41:42PM +0300, Cyrill Gorcunov wrote: > > > When skb_copy_datagram_iovec called to fetch queued data > > > it may fail with EFAULT and if MSG_PEEK set by a caller > > > the position get advanced even if data hasn't been read. > > > So we might loose data bits here on subsequent recvmsg > > > calls. Instead lets exit early with error. > > > > > > In sake of https://jira.sw.ru/browse/PSBM-57921 > > > > > > CC: Andrey Vagin <ava...@openvz.org> > > > Signed-off-by: Cyrill Gorcunov <gorcu...@openvz.org> > > > --- > > > net/netlink/af_netlink.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > Index: linux-pcs7.git/net/netlink/af_netlink.c > > > =================================================================== > > > --- linux-pcs7.git.orig/net/netlink/af_netlink.c > > > +++ linux-pcs7.git/net/netlink/af_netlink.c > > > @@ -2473,6 +2473,10 @@ static int netlink_recvmsg(struct kiocb > > > > > > skb_reset_transport_header(data_skb); > > > err = skb_copy_datagram_iovec(data_skb, skip, msg->msg_iov, copied); > > > + if (err) { > > > + skb_free_datagram(sk, skb); > > > > hmmm, why do we need to call skb_free_datagram? > > It should be ok, skb_free_datagram() decriments a reference counter > > Acked-by: Andrey Vagin <ava...@virtuozzo.com>
Actually, this patch breaks the old behaviour even when MSG_PEEK isn't set. I was thinking a bit more and I don't understand why it is a problem. If we can't fill a buffer, an error will be returned and a user will be able to set peek_offset to get these data again. > > > > + goto out; > > > + } > > > > > > if (flags & MSG_PEEK) > > > sk_peek_offset_fwd(sk, copied); > > _______________________________________________ > > Devel mailing list > > Devel@openvz.org > > https://lists.openvz.org/mailman/listinfo/devel > _______________________________________________ > Devel mailing list > Devel@openvz.org > https://lists.openvz.org/mailman/listinfo/devel _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel