diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index fc6d7d143f2c..844642682b83 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1682,16 +1682,16 @@ static int grec_size(struct ifmcaddr6 *pmc, int type, int gdel, int sdel) } static struct sk_buff *add_grhead(struct sk_buff *skb, struct ifmcaddr6 *pmc, - int type, struct mld2_grec **ppgr) + int type, struct mld2_grec **ppgr, unsigned int mtu) { - struct net_device *dev = pmc->idev->dev; struct mld2_report *pmr; struct mld2_grec *pgr; - if (!skb) - skb = mld_newpack(pmc->idev, dev->mtu); - if (!skb) - return NULL; + if (!skb) { + skb = mld_newpack(pmc->idev, mtu); + if (!skb) + return NULL; + } pgr = skb_put(skb, sizeof(struct mld2_grec)); pgr->grec_type = type; pgr->grec_auxwords = 0; @@ -1714,10 +1714,15 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, struct mld2_grec *pgr = NULL; struct ip6_sf_list *psf, *psf_next, *psf_prev, **psf_list; int scount, stotal, first, isquery, truncate; + unsigned int mtu; if (pmc->mca_flags & MAF_NOREPORT) return skb; + mtu = READ_ONCE(dev->mtu); + if (mtu < IPV6_MIN_MTU) + return skb; + isquery = type == MLD2_MODE_IS_INCLUDE || type == MLD2_MODE_IS_EXCLUDE; truncate = type == MLD2_MODE_IS_EXCLUDE || @@ -1738,7 +1743,7 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, AVAILABLE(skb) < grec_size(pmc, type, gdeleted, sdeleted)) { if (skb) mld_sendpack(skb); - skb = mld_newpack(idev, dev->mtu); + skb = mld_newpack(idev, mtu); } } first = 1; @@ -1774,12 +1779,12 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, pgr->grec_nsrcs = htons(scount); if (skb) mld_sendpack(skb); - skb = mld_newpack(idev, dev->mtu); + skb = mld_newpack(idev, mtu); first = 1; scount = 0; } if (first) { - skb = add_grhead(skb, pmc, type, &pgr); + skb = add_grhead(skb, pmc, type, &pgr, mtu); first = 0; } if (!skb) @@ -1814,7 +1819,7 @@ empty_source: mld_sendpack(skb); skb = NULL; /* add_grhead will get a new one */ } - skb = add_grhead(skb, pmc, type, &pgr); + skb = add_grhead(skb, pmc, type, &pgr, mtu); } } if (pgr)