[PATCH 6.18 079/198] net: increase IP_TUNNEL_RECURSION_LIMIT to 5

Greg Kroah-Hartman
2026-04-20T16:02:01Z

From: Chris J Arges <carges@cloudflare.com>

[ Upstream commit 77facb35227c421467cdb49268de433168c2dcef ]

In configurations with multiple tunnel layers and MPLS lwtunnel routing, a
single tunnel hop can increment the counter beyond this limit. This causes
packets to be dropped with the "Dead loop on virtual device" message even
when a routing loop doesn't exist.

Increase IP_TUNNEL_RECURSION_LIMIT from 4 to 5 to handle this use-case.

Fixes: 6f1a9140ecda ("net: add xmit recursion limit to tunnel xmit functions")
Link: https://lore.kernel.org/netdev/88deb91b-ef1b-403c-8eeb-0f971f27e34f@redhat.com/
Signed-off-by: Chris J Arges <carges@cloudflare.com>
Link: https://patch.msgid.link/20260402222401.3408368-1-carges@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/ip_tunnels.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 80662f8120803..253ed3930f6ef 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -32,7 +32,7 @@
* recursion involves route lookups and full IP output, consuming much
* more stack per level, so a lower limit is needed.
*/
-#define IP_TUNNEL_RECURSION_LIMIT 4
+#define IP_TUNNEL_RECURSION_LIMIT 5

/* Keep error state on tunnel for 30 sec */
#define IPTUNNEL_ERR_TIMEO (30*HZ)
--
2.53.0