[PATCH 6.18 164/212] netdevsim: drop PSP ext ref on forward failure

Greg Kroah-Hartman
2026-03-23T14:09:03Z

From: Wesley Atwell <atwellwea@gmail.com>

[ Upstream commit 7d9351435ebba08bbb60f42793175c9dc714d2fb ]

nsim_do_psp() takes an extra reference to the PSP skb extension so the
extension survives __dev_forward_skb(). That forward path scrubs the skb
and drops attached skb extensions before nsim_psp_handle_ext() can
reattach the PSP metadata.

If __dev_forward_skb() fails in nsim_forward_skb(), the function returns
before nsim_psp_handle_ext() can attach that extension to the skb, leaving
the extra reference leaked.

Drop the saved PSP extension reference before returning from the
forward-failure path. Guard the put because plain or non-decapsulated
traffic can also fail forwarding without ever taking the extra PSP
reference.

Fixes: f857478d6206 ("netdevsim: a basic test PSP implementation")
Signed-off-by: Wesley Atwell <atwellwea@gmail.com>
Reviewed-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20260317061431.1482716-1-atwellwea@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/netdevsim/netdev.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index fa1d97885caaf..06446b03cd9bc 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -109,8 +109,11 @@ static int nsim_forward_skb(struct net_device *tx_dev,
int ret;

ret = __dev_forward_skb(rx_dev, skb);
- if (ret)
+ if (ret) {
+ if (psp_ext)
+ __skb_ext_put(psp_ext);
return ret;
+ }

nsim_psp_handle_ext(skb, psp_ext);

--
2.51.0