Merge remote-tracking branch 'remotes/fslc/4.9-2.3.x-imx' into toradex_4.9-2.3.x-imx-nextColibri-iMX7_LXDE-Image_2.8b6.184-20190401Colibri-iMX6_LXDE-Image_2.8b6.184-20190401Colibri-iMX6ULL_LXDE-Image_2.8b6.184-20190401Apalis-iMX6_LXDE-Image_2.8b6.184-20190401

21 files changed, 170 insertions, 58 deletions

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 571d079e262f..71bcab94c5c7 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -667,7 +667,8 @@ static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
 	case CIPSO_V4_MAP_PASS:
 		return 0;
 	case CIPSO_V4_MAP_TRANS:
-		if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL)
+		if ((level < doi_def->map.std->lvl.cipso_size) &&
+		    (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL))
 			return 0;
 		break;
 	}
@@ -1735,13 +1736,26 @@ validate_return:
  */
 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
 {
+	unsigned char optbuf[sizeof(struct ip_options) + 40];
+	struct ip_options *opt = (struct ip_options *)optbuf;
+
 	if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
 		return;
 
+	/*
+	 * We might be called above the IP layer,
+	 * so we can not use icmp_send and IPCB here.
+	 */
+
+	memset(opt, 0, sizeof(struct ip_options));
+	opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
+	if (__ip_options_compile(dev_net(skb->dev), opt, skb, NULL))
+		return;
+
 	if (gateway)
-		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
+		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, opt);
 	else
-		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
+		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, opt);
 }
 
 /**
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 9364c39d0555..cbe3fdba4a2c 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -193,7 +193,7 @@ static void fib_flush(struct net *net)
 		struct fib_table *tb;
 
 		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
-			flushed += fib_table_flush(net, tb);
+			flushed += fib_table_flush(net, tb, false);
 	}
 
 	if (flushed)
@@ -1277,7 +1277,7 @@ static void ip_fib_net_exit(struct net *net)
 
 		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
 			hlist_del(&tb->tb_hlist);
-			fib_table_flush(net, tb);
+			fib_table_flush(net, tb, true);
 			fib_free_table(tb);
 		}
 	}
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index ef40bb659a7a..36f0a8c581d0 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1826,7 +1826,7 @@ void fib_table_flush_external(struct fib_table *tb)
 }
 
 /* Caller must hold RTNL. */
-int fib_table_flush(struct net *net, struct fib_table *tb)
+int fib_table_flush(struct net *net, struct fib_table *tb, bool flush_all)
 {
 	struct trie *t = (struct trie *)tb->tb_data;
 	struct key_vector *pn = t->kv;
@@ -1874,7 +1874,17 @@ int fib_table_flush(struct net *net, struct fib_table *tb)
 		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
 			struct fib_info *fi = fa->fa_info;
 
-			if (!fi || !(fi->fib_flags & RTNH_F_DEAD)) {
+			if (!fi ||
+			    (!(fi->fib_flags & RTNH_F_DEAD) &&
+			     !fib_props[fa->fa_type].error)) {
+				slen = fa->fa_slen;
+				continue;
+			}
+
+			/* Do not flush error routes if network namespace is
+			 * not being dismantled
+			 */
+			if (!flush_all && fib_props[fa->fa_type].error) {
 				slen = fa->fa_slen;
 				continue;
 			}
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 31f17f0bbd1c..172d3dfed0c4 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -565,7 +565,8 @@ relookup_failed:
  *			MUST reply to only the first fragment.
  */
 
-void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
+void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
+		 const struct ip_options *opt)
 {
 	struct iphdr *iph;
 	int room;
@@ -679,7 +680,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
 					  iph->tos;
 	mark = IP4_REPLY_MARK(net, skb_in->mark);
 
-	if (ip_options_echo(&icmp_param->replyopts.opt.opt, skb_in))
+	if (__ip_options_echo(&icmp_param->replyopts.opt.opt, skb_in, opt))
 		goto out_unlock;
 
 
@@ -731,7 +732,7 @@ out_free:
 	kfree(icmp_param);
 out:;
 }
-EXPORT_SYMBOL(icmp_send);
+EXPORT_SYMBOL(__icmp_send);
 
 
 static void icmp_socket_deliver(struct sk_buff *skb, u32 info)
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 528a6777cda0..1bcbb7399fe6 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -790,7 +790,6 @@ static void inet_child_forget(struct sock *sk, struct request_sock *req,
 		tcp_sk(child)->fastopen_rsk = NULL;
 	}
 	inet_csk_destroy_sock(child);
-	reqsk_put(req);
 }
 
 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
@@ -861,6 +860,7 @@ void inet_csk_listen_stop(struct sock *sk)
 		sock_hold(child);
 
 		inet_child_forget(sk, req, child);
+		reqsk_put(req);
 		bh_unlock_sock(child);
 		local_bh_enable();
 		sock_put(child);
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index 5a8c26c9872d..0fb49dedc9fb 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -90,7 +90,7 @@ static void inet_frags_free_cb(void *ptr, void *arg)
 
 void inet_frags_exit_net(struct netns_frags *nf)
 {
-	nf->low_thresh = 0; /* prevent creation of new frags */
+	nf->high_thresh = 0; /* prevent creation of new frags */
 
 	rhashtable_free_and_destroy(&nf->rhashtable, inet_frags_free_cb, NULL);
 }
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 86fa45809540..0c5862914f05 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -448,6 +448,7 @@ relookup:
 		atomic_set(&p->rid, 0);
 		p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW;
 		p->rate_tokens = 0;
+		p->n_redirects = 0;
 		/* 60*HZ is arbitrary, but chosen enough high so that the first
 		 * calculation of tokens is at its maximum.
 		 */
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 80e48f40c3a8..c7334d1e392a 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -345,10 +345,10 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 	struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
 	struct rb_node **rbn, *parent;
 	struct sk_buff *skb1, *prev_tail;
+	int ihl, end, skb1_run_end;
 	struct net_device *dev;
 	unsigned int fragsize;
 	int flags, offset;
-	int ihl, end;
 	int err = -ENOENT;
 	u8 ecn;
 
@@ -418,9 +418,12 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 	 *   overlapping fragment, the entire datagram (and any constituent
 	 *   fragments) MUST be silently discarded.
 	 *
-	 * We do the same here for IPv4 (and increment an snmp counter).
+	 * We do the same here for IPv4 (and increment an snmp counter) but
+	 * we do not want to drop the whole queue in response to a duplicate
+	 * fragment.
 	 */
 
+	err = -EINVAL;
 	/* Find out where to put this fragment.  */
 	prev_tail = qp->q.fragments_tail;
 	if (!prev_tail)
@@ -442,13 +445,17 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 		do {
 			parent = *rbn;
 			skb1 = rb_to_skb(parent);
+			skb1_run_end = skb1->ip_defrag_offset +
+				       FRAG_CB(skb1)->frag_run_len;
 			if (end <= skb1->ip_defrag_offset)
 				rbn = &parent->rb_left;
-			else if (offset >= skb1->ip_defrag_offset +
-						FRAG_CB(skb1)->frag_run_len)
+			else if (offset >= skb1_run_end)
 				rbn = &parent->rb_right;
-			else /* Found an overlap with skb1. */
-				goto discard_qp;
+			else if (offset >= skb1->ip_defrag_offset &&
+				 end <= skb1_run_end)
+				goto err; /* No new data, potential duplicate */
+			else
+				goto discard_qp; /* Found an overlap */
 		} while (*rbn);
 		/* Here we have parent properly set, and rbn pointing to
 		 * one of its NULL left/right children. Insert skb.
@@ -493,7 +500,6 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 
 discard_qp:
 	inet_frag_kill(&qp->q);
-	err = -EINVAL;
 	__IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
 err:
 	kfree_skb(skb);
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index d6feabb03516..bcadca26523b 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -475,6 +475,7 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 		goto drop;
 	}
 
+	iph = ip_hdr(skb);
 	skb->transport_header = skb->network_header + iph->ihl*4;
 
 	/* Remove any debris in the socket control block */
diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index 4d158ff1def1..4cd3b5ad9cee 100644
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -253,8 +253,9 @@ static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb)
  * If opt == NULL, then skb->data should point to IP header.
  */
 
-int ip_options_compile(struct net *net,
-		       struct ip_options *opt, struct sk_buff *skb)
+int __ip_options_compile(struct net *net,
+			 struct ip_options *opt, struct sk_buff *skb,
+			 __be32 *info)
 {
 	__be32 spec_dst = htonl(INADDR_ANY);
 	unsigned char *pp_ptr = NULL;
@@ -470,11 +471,22 @@ eol:
 		return 0;
 
 error:
-	if (skb) {
-		icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
-	}
+	if (info)
+		*info = htonl((pp_ptr-iph)<<24);
 	return -EINVAL;
 }
+
+int ip_options_compile(struct net *net,
+		       struct ip_options *opt, struct sk_buff *skb)
+{
+	int ret;
+	__be32 info;
+
+	ret = __ip_options_compile(net, opt, skb, &info);
+	if (ret != 0 && skb)
+		icmp_send(skb, ICMP_PARAMETERPROB, 0, info);
+	return ret;
+}
 EXPORT_SYMBOL(ip_options_compile);
 
 /*
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index a5851c0bc278..e39895ea1b77 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -133,19 +133,17 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 
 static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
 {
+	__be16 _ports[2], *ports;
 	struct sockaddr_in sin;
-	__be16 *ports;
-	int end;
-
-	end = skb_transport_offset(skb) + 4;
-	if (end > 0 && !pskb_may_pull(skb, end))
-		return;
 
 	/* All current transport protocols have the port numbers in the
 	 * first four bytes of the transport header and this function is
 	 * written with this assumption in mind.
 	 */
-	ports = (__be16 *)skb_transport_header(skb);
+	ports = skb_header_pointer(skb, skb_transport_offset(skb),
+				   sizeof(_ports), &_ports);
+	if (!ports)
+		return;
 
 	sin.sin_family = AF_INET;
 	sin.sin_addr.s_addr = ip_hdr(skb)->daddr;
diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index cbff0d6ff1ac..270e79f4d40e 100644
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -74,6 +74,33 @@ drop:
 	return 0;
 }
 
+static int vti_input_ipip(struct sk_buff *skb, int nexthdr, __be32 spi,
+		     int encap_type)
+{
+	struct ip_tunnel *tunnel;
+	const struct iphdr *iph = ip_hdr(skb);
+	struct net *net = dev_net(skb->dev);
+	struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
+
+	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
+				  iph->saddr, iph->daddr, 0);
+	if (tunnel) {
+		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
+			goto drop;
+
+		XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = tunnel;
+
+		skb->dev = tunnel->dev;
+
+		return xfrm_input(skb, nexthdr, spi, encap_type);
+	}
+
+	return -EINVAL;
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
 static int vti_rcv(struct sk_buff *skb)
 {
 	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
@@ -82,6 +109,14 @@ static int vti_rcv(struct sk_buff *skb)
 	return vti_input(skb, ip_hdr(skb)->protocol, 0, 0);
 }
 
+static int vti_rcv_ipip(struct sk_buff *skb)
+{
+	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
+	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
+
+	return vti_input_ipip(skb, ip_hdr(skb)->protocol, ip_hdr(skb)->saddr, 0);
+}
+
 static int vti_rcv_cb(struct sk_buff *skb, int err)
 {
 	unsigned short family;
@@ -439,6 +474,12 @@ static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = {
 	.priority	=	100,
 };
 
+static struct xfrm_tunnel ipip_handler __read_mostly = {
+	.handler	=	vti_rcv_ipip,
+	.err_handler	=	vti4_err,
+	.priority	=	0,
+};
+
 static int __net_init vti_init_net(struct net *net)
 {
 	int err;
@@ -622,6 +663,13 @@ static int __init vti_init(void)
 	if (err < 0)
 		goto xfrm_proto_comp_failed;
 
+	msg = "ipip tunnel";
+	err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
+	if (err < 0) {
+		pr_info("%s: cant't register tunnel\n",__func__);
+		goto xfrm_tunnel_failed;
+	}
+
 	msg = "netlink interface";
 	err = rtnl_link_register(&vti_link_ops);
 	if (err < 0)
@@ -631,6 +679,8 @@ static int __init vti_init(void)
 
 rtnl_link_failed:
 	xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
+xfrm_tunnel_failed:
+	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
 xfrm_proto_comp_failed:
 	xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 xfrm_proto_ah_failed:
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 742a3432c3ea..354926e61f06 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -68,6 +68,8 @@
 #include <linux/netconf.h>
 #include <net/nexthop.h>
 
+#include <linux/nospec.h>
+
 struct ipmr_rule {
 	struct fib_rule		common;
 };
@@ -1562,6 +1564,7 @@ int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
 			return -EFAULT;
 		if (vr.vifi >= mrt->maxvif)
 			return -EINVAL;
+		vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
 		read_lock(&mrt_lock);
 		vif = &mrt->vif_table[vr.vifi];
 		if (VIF_EXISTS(mrt, vr.vifi)) {
diff --git a/net/ipv4/netfilter/nft_masq_ipv4.c b/net/ipv4/netfilter/nft_masq_ipv4.c
index 51ced81b616c..dc3628a396ec 100644
--- a/net/ipv4/netfilter/nft_masq_ipv4.c
+++ b/net/ipv4/netfilter/nft_masq_ipv4.c
@@ -26,10 +26,10 @@ static void nft_masq_ipv4_eval(const struct nft_expr *expr,
 	memset(&range, 0, sizeof(range));
 	range.flags = priv->flags;
 	if (priv->sreg_proto_min) {
-		range.min_proto.all =
-			*(__be16 *)&regs->data[priv->sreg_proto_min];
-		range.max_proto.all =
-			*(__be16 *)&regs->data[priv->sreg_proto_max];
+		range.min_proto.all = (__force __be16)nft_reg_load16(
+			&regs->data[priv->sreg_proto_min]);
+		range.max_proto.all = (__force __be16)nft_reg_load16(
+			&regs->data[priv->sreg_proto_max]);
 	}
 	regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, pkt->hook,
 						    &range, pkt->out);
diff --git a/net/ipv4/netfilter/nft_redir_ipv4.c b/net/ipv4/netfilter/nft_redir_ipv4.c
index c09d4381427e..f760524e1353 100644
--- a/net/ipv4/netfilter/nft_redir_ipv4.c
+++ b/net/ipv4/netfilter/nft_redir_ipv4.c
@@ -26,10 +26,10 @@ static void nft_redir_ipv4_eval(const struct nft_expr *expr,
 
 	memset(&mr, 0, sizeof(mr));
 	if (priv->sreg_proto_min) {
-		mr.range[0].min.all =
-			*(__be16 *)&regs->data[priv->sreg_proto_min];
-		mr.range[0].max.all =
-			*(__be16 *)&regs->data[priv->sreg_proto_max];
+		mr.range[0].min.all = (__force __be16)nft_reg_load16(
+			&regs->data[priv->sreg_proto_min]);
+		mr.range[0].max.all = (__force __be16)nft_reg_load16(
+			&regs->data[priv->sreg_proto_max]);
 		mr.range[0].flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
 	}
 
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 890141d32ab9..c42fb2330b45 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -882,13 +882,15 @@ void ip_rt_send_redirect(struct sk_buff *skb)
 	/* No redirected packets during ip_rt_redirect_silence;
 	 * reset the algorithm.
 	 */
-	if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
+	if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
 		peer->rate_tokens = 0;
+		peer->n_redirects = 0;
+	}
 
 	/* Too many ignored redirects; do not send anything
 	 * set dst.rate_last to the last seen redirected packet.
 	 */
-	if (peer->rate_tokens >= ip_rt_redirect_number) {
+	if (peer->n_redirects >= ip_rt_redirect_number) {
 		peer->rate_last = jiffies;
 		goto out_put_peer;
 	}
@@ -905,6 +907,7 @@ void ip_rt_send_redirect(struct sk_buff *skb)
 		icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
 		peer->rate_last = jiffies;
 		++peer->rate_tokens;
+		++peer->n_redirects;
 #ifdef CONFIG_IP_ROUTE_VERBOSE
 		if (log_martians &&
 		    peer->rate_tokens == ip_rt_redirect_number)
@@ -1610,6 +1613,10 @@ static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
 		if (fnhe->fnhe_daddr == daddr) {
 			rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
 				fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
+			/* set fnhe_daddr to 0 to ensure it won't bind with
+			 * new dsts in rt_bind_exception().
+			 */
+			fnhe->fnhe_daddr = 0;
 			fnhe_flush_routes(fnhe);
 			kfree_rcu(fnhe, rcu);
 			break;
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 0597ad73a1fa..b596c413d297 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -225,7 +225,12 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
 	if (child) {
 		atomic_set(&req->rsk_refcnt, 1);
 		sock_rps_save_rxhash(child, skb);
-		inet_csk_reqsk_queue_add(sk, req, child);
+		if (!inet_csk_reqsk_queue_add(sk, req, child)) {
+			bh_unlock_sock(child);
+			sock_put(child);
+			child = NULL;
+			reqsk_put(req);
+		}
 	} else {
 		reqsk_free(req);
 	}
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9de77d946f5a..2ededb32b754 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2292,7 +2292,6 @@ int tcp_disconnect(struct sock *sk, int flags)
 	tp->write_seq += tp->max_window + 2;
 	if (tp->write_seq == 0)
 		tp->write_seq = 1;
-	icsk->icsk_backoff = 0;
 	tp->snd_cwnd = 2;
 	icsk->icsk_probes_out = 0;
 	tp->packets_out = 0;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index dbb153c6b21a..cd4f13dda49e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6374,13 +6374,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 			goto drop;
 	}
 
-
-	/* Accept backlog is full. If we have already queued enough
-	 * of warm entries in syn queue, drop request. It is better than
-	 * clogging syn queue with openreqs with exponentially increasing
-	 * timeout.
-	 */
-	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) {
+	if (sk_acceptq_is_full(sk)) {
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
 		goto drop;
 	}
@@ -6479,7 +6473,13 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 		af_ops->send_synack(fastopen_sk, dst, &fl, req,
 				    &foc, TCP_SYNACK_FASTOPEN);
 		/* Add the child socket directly into the accept queue */
-		inet_csk_reqsk_queue_add(sk, req, fastopen_sk);
+		if (!inet_csk_reqsk_queue_add(sk, req, fastopen_sk)) {
+			reqsk_fastopen_remove(fastopen_sk, req, false);
+			bh_unlock_sock(fastopen_sk);
+			sock_put(fastopen_sk);
+			reqsk_put(req);
+			goto drop;
+		}
 		sk->sk_data_ready(sk);
 		bh_unlock_sock(fastopen_sk);
 		sock_put(fastopen_sk);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1ea0c91ba994..82c1064ff4aa 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -464,14 +464,15 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 		if (sock_owned_by_user(sk))
 			break;
 
+		skb = tcp_write_queue_head(sk);
+		if (WARN_ON_ONCE(!skb))
+			break;
+
 		icsk->icsk_backoff--;
 		icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
 					       TCP_TIMEOUT_INIT;
 		icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
 
-		skb = tcp_write_queue_head(sk);
-		BUG_ON(!skb);
-
 		remaining = icsk->icsk_rto -
 			    min(icsk->icsk_rto,
 				tcp_time_stamp - tcp_skb_timestamp(skb));
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index bd68f073570b..6f35cdd5f2f0 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2346,14 +2346,18 @@ void tcp_send_loss_probe(struct sock *sk)
 		skb = tcp_write_queue_tail(sk);
 	}
 
+	if (unlikely(!skb)) {
+		WARN_ONCE(tp->packets_out,
+			  "invalid inflight: %u state %u cwnd %u mss %d\n",
+			  tp->packets_out, sk->sk_state, tp->snd_cwnd, mss);
+		inet_csk(sk)->icsk_pending = 0;
+		return;
+	}
+
 	/* At most one outstanding TLP retransmission. */
 	if (tp->tlp_high_seq)
 		goto rearm_timer;
 
-	/* Retransmit last segment. */
-	if (WARN_ON(!skb))
-		goto rearm_timer;
-
 	if (skb_still_in_host_queue(sk, skb))
 		goto rearm_timer;