Merge: geneve: fetching stats vs destroy race

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6932

JIRA: https://issues.redhat.com/browse/RHEL-93467

the device per cpu tstats are destroyed at uninit time, but OVS (and even NL I suspect) could still reach for them even later. Using the core helpers move the stats free at netdevice deallocation time, closing the race.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Approved-by: Guillaume Nault <gnault@redhat.com>
Approved-by: Lenny Szubowicz <lszubowi@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

drivers/net/geneve.c

@@ -328,19 +328,12 @@ static int geneve_init(struct net_device *dev)
 	struct geneve_dev *geneve = netdev_priv(dev);
 	int err;
 
-	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!dev->tstats)
-		return -ENOMEM;
-
 	err = gro_cells_init(&geneve->gro_cells, dev);
-	if (err) {
-		free_percpu(dev->tstats);
+	if (err)
 		return err;
-	}
 
 	err = dst_cache_init(&geneve->cfg.info.dst_cache, GFP_KERNEL);
 	if (err) {
-		free_percpu(dev->tstats);
 		gro_cells_destroy(&geneve->gro_cells);
 		return err;
 	}
@@ -354,7 +347,6 @@ static void geneve_uninit(struct net_device *dev)
 
 	dst_cache_destroy(&geneve->cfg.info.dst_cache);
 	gro_cells_destroy(&geneve->gro_cells);
-	free_percpu(dev->tstats);
 }
 
 /* Callback from net/ipv4/udp.c to receive packets */
@@ -1190,6 +1182,7 @@ static void geneve_setup(struct net_device *dev)
 	dev->hw_features |= NETIF_F_RXCSUM;
 	dev->hw_features |= NETIF_F_GSO_SOFTWARE;
 
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	/* MTU range: 68 - (something less than 65535) */
 	dev->min_mtu = ETH_MIN_MTU;
 	/* The max_mtu calculation does not take account of GENEVE