[PATCH 6.19 130/220] ip_tunnel: adapt iptunnel_xmit_stats() to NETDEV_PCPU_STAT_DSTATS

Greg Kroah-Hartman
2026-03-23T13:56:01Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 8431c602f551549f082bbfa67f3003f2d8e3e132 ]

Blamed commits forgot that vxlan/geneve use udp_tunnel[6]_xmit_skb() which
call iptunnel_xmit_stats().

iptunnel_xmit_stats() was assuming tunnels were only using
NETDEV_PCPU_STAT_TSTATS.

@syncp offset in pcpu_sw_netstats and pcpu_dstats is different.

32bit kernels would either have corruptions or freezes if the syncp
sequence was overwritten.

This patch also moves pcpu_stat_type closer to dev->{t,d}stats to avoid
a potential cache line miss since iptunnel_xmit_stats() needs to read it.

Fixes: 6fa6de302246 ("geneve: Handle stats using NETDEV_PCPU_STAT_DSTATS.")
Fixes: be226352e8dc ("vxlan: Handle stats using NETDEV_PCPU_STAT_DSTATS.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Link: https://patch.msgid.link/20260311123110.1471930-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/netdevice.h | 3 +--
include/net/ip_tunnels.h | 30 +++++++++++++++++++++++-------
2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 65d85dc9c8f05..444e52eb8ed99 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2153,6 +2153,7 @@ struct net_device {
unsigned long state;
unsigned int flags;
unsigned short hard_header_len;
+ enum netdev_stat_type pcpu_stat_type:8;
netdev_features_t features;
struct inet6_dev __rcu *ip6_ptr;
__cacheline_group_end(net_device_read_txrx);
@@ -2401,8 +2402,6 @@ struct net_device {
void *ml_priv;
enum netdev_ml_priv_type ml_priv_type;

- enum netdev_stat_type pcpu_stat_type:8;
-
#if IS_ENABLED(CONFIG_GARP)
struct garp_port __rcu *garp_port;
#endif
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 80662f8120803..1f577a4f8ce9b 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -665,13 +665,29 @@ static inline int iptunnel_pull_offloads(struct sk_buff *skb)
static inline void iptunnel_xmit_stats(struct net_device *dev, int pkt_len)
{
if (pkt_len > 0) {
- struct pcpu_sw_netstats *tstats = get_cpu_ptr(dev->tstats);
-
- u64_stats_update_begin(&tstats->syncp);
- u64_stats_add(&tstats->tx_bytes, pkt_len);
- u64_stats_inc(&tstats->tx_packets);
- u64_stats_update_end(&tstats->syncp);
- put_cpu_ptr(tstats);
+ if (dev->pcpu_stat_type == NETDEV_PCPU_STAT_DSTATS) {
+ struct pcpu_dstats *dstats = get_cpu_ptr(dev->dstats);
+
+ u64_stats_update_begin(&dstats->syncp);
+ u64_stats_add(&dstats->tx_bytes, pkt_len);
+ u64_stats_inc(&dstats->tx_packets);
+ u64_stats_update_end(&dstats->syncp);
+ put_cpu_ptr(dstats);
+ return;
+ }
+ if (dev->pcpu_stat_type == NETDEV_PCPU_STAT_TSTATS) {
+ struct pcpu_sw_netstats *tstats = get_cpu_ptr(dev->tstats);
+
+ u64_stats_update_begin(&tstats->syncp);
+ u64_stats_add(&tstats->tx_bytes, pkt_len);
+ u64_stats_inc(&tstats->tx_packets);
+ u64_stats_update_end(&tstats->syncp);
+ put_cpu_ptr(tstats);
+ return;
+ }
+ pr_err_once("iptunnel_xmit_stats pcpu_stat_type=%d\n",
+ dev->pcpu_stat_type);
+ WARN_ON_ONCE(1);
return;
}

--
2.51.0