[PATCH] net: pfcp: allocate per-cpu tstats for PFCP netdevs

[PATCH] net: pfcp: allocate per-cpu tstats for PFCP netdevs

[Samuel Moelius]

PFCP uses dev_get_tstats64() as its ndo_get_stats64 callback, but
pfcp_link_setup() does not request NETDEV_PCPU_STAT_TSTATS.  The net
core therefore leaves dev->tstats NULL for PFCP devices.

Creating a PFCP rtnetlink device can immediately ask the new netdev for
stats while building the RTM_NEWLINK notification.  That reaches
dev_get_tstats64() and dereferences the NULL dev->tstats pointer.

Set pcpu_stat_type to NETDEV_PCPU_STAT_TSTATS during PFCP link setup so
the net core allocates the storage expected by dev_get_tstats64().

Assisted-by: Codex:gpt-5.5-cyber-preview
Signed-off-by: Samuel Moelius <sam.moelius@trailofbits.com>
---
 drivers/net/pfcp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/pfcp.c b/drivers/net/pfcp.c
index 28e6bc4a1f14..a6aa30ae0af7 100644
--- a/drivers/net/pfcp.c
+++ b/drivers/net/pfcp.c
@@ -148,6 +148,7 @@ static void pfcp_link_setup(struct net_device *dev)
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 	dev->priv_flags |= IFF_NO_QUEUE;
 
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	netif_keep_dst(dev);
 }
 
-- 
2.43.0

Re: [PATCH] net: pfcp: allocate per-cpu tstats for PFCP netdevs

[Eric Dumazet]

On Fri, Jun 5, 2026 at 8:13 AM Samuel Moelius
<sam.moelius@trailofbits.com> wrote:
>
> PFCP uses dev_get_tstats64() as its ndo_get_stats64 callback, but
> pfcp_link_setup() does not request NETDEV_PCPU_STAT_TSTATS.  The net
> core therefore leaves dev->tstats NULL for PFCP devices.
>
> Creating a PFCP rtnetlink device can immediately ask the new netdev for
> stats while building the RTM_NEWLINK notification.  That reaches
> dev_get_tstats64() and dereferences the NULL dev->tstats pointer.
>
> Set pcpu_stat_type to NETDEV_PCPU_STAT_TSTATS during PFCP link setup so
> the net core allocates the storage expected by dev_get_tstats64().
>
> Assisted-by: Codex:gpt-5.5-cyber-preview
> Signed-off-by: Samuel Moelius <sam.moelius@trailofbits.com>
> ---
>  drivers/net/pfcp.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/pfcp.c b/drivers/net/pfcp.c
> index 28e6bc4a1f14..a6aa30ae0af7 100644
> --- a/drivers/net/pfcp.c
> +++ b/drivers/net/pfcp.c
> @@ -148,6 +148,7 @@ static void pfcp_link_setup(struct net_device *dev)
>         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
>         dev->priv_flags |= IFF_NO_QUEUE;
>
> +       dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
>         netif_keep_dst(dev);
>  }
>

We request Fixes: tags in networking tree.

Please look at Documentation/process/maintainer-netdev.rst