From: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx> commit 45a36a18d01907710bad5258d81f76c18882ad88 upstream. xfrm interfaces currently test for !skb->ignore_df when deciding whether to update the pmtu on the skb's dst. Because of this, no pmtu exception is created when we do something like: ping -s 1438 <dest> By dropping this check, the pmtu exception will be created and the next ping attempt will work. Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces") Reported-by: Xiumei Mu <xmu@xxxxxxxxxx> Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx> Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/xfrm/xfrm_interface.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/xfrm/xfrm_interface.c +++ b/net/xfrm/xfrm_interface.c @@ -293,7 +293,7 @@ xfrmi_xmit2(struct sk_buff *skb, struct } mtu = dst_mtu(dst); - if (!skb->ignore_df && skb->len > mtu) { + if (skb->len > mtu) { skb_dst_update_pmtu_no_confirm(skb, mtu); if (skb->protocol == htons(ETH_P_IPV6)) {