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From: Chris Arges <carges@cloudflare.com>
To: Weiming Shi <bestswngs@gmail.com>,
	Eric Dumazet <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com,
	jgriege@cloudflare.com
Subject: [REGRESSION] net: add xmit recursion limit to tunnel xmit functions
Date: Tue, 31 Mar 2026 15:09:33 -0500	[thread overview]
Message-ID: <acwp_cVAflwTQCBh@20HS2G4> (raw)

Hello,

Commit 6f1a9140ecda ("net: add xmit recursion limit to tunnel xmit functions")
introduces a regression in our systems using legitimate multi-level tunnel
encapsulation stacks. Our testing was with stable 6.12.y and 6.18.y where this
patch was backported.

One of the usecases we have are packets being sent to a GRE device, then
MPLS/LWT route, then IPIP device, then SIT/FOU device. What we observed is that
packets are getting dropped at the last device and we get the message "Dead
loop on virtual device" sent from the iptunnel_xmit function.

I'm looking for some approaches to retain the mitigation while still having a
recursion limit. One idea is to just increase the limit. Happy to provide
additional testing and debugging.

Thanks,
--chris

             reply	other threads:[~2026-03-31 20:09 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-31 20:09 Chris Arges [this message]
2026-04-02  0:38 ` [REGRESSION] net: add xmit recursion limit to tunnel xmit functions Jakub Kicinski
2026-04-02  9:31   ` Paolo Abeni

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