From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f174.google.com (mail-oi1-f174.google.com [209.85.167.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 741C738F93D for ; Tue, 31 Mar 2026 20:09:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774987778; cv=none; b=kM0WJcFdttkFJ/8NOMwQjkOMsTWeiRaeUB5O6IpbM1FWOHx97Ed5lKWe6ScR6YtPLctgUZLfq1fuzAyWCb5Y7g9fjWTv7ps1Wg0ZJfuFycntPKWuW0Vejfw9Ij89BXaNYuefQlw3KLS0Q8YNjZFtfgW3wKlRHkiLAb0BToHKul4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774987778; c=relaxed/simple; bh=FhNqwVSQY4PYFF8G5roI2acw0d3B6JJ9JEkTmXmuARI=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=KDvNQP7m6zCWVItVFYqP9yssAnO1nW88eTrKqgO7CajVIwnxvHXiH4zZpb+R1pwzPW4/3LyZintLuyz+Haq0GV9lO6a8t2IJAImPQ36oU+WdyTy6lcBUc8a7vMjVNTHXZVeS2i0wVZ4NPuV7Jd9aGa9ZVYgVsMqOPpXHzp7/flk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com; spf=pass smtp.mailfrom=cloudflare.com; dkim=pass (2048-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b=UV5gQCT1; arc=none smtp.client-ip=209.85.167.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=cloudflare.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="UV5gQCT1" Received: by mail-oi1-f174.google.com with SMTP id 5614622812f47-467fd082ffeso3815294b6e.1 for ; Tue, 31 Mar 2026 13:09:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google09082023; t=1774987776; x=1775592576; darn=vger.kernel.org; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :from:to:cc:subject:date:message-id:reply-to; bh=FhNqwVSQY4PYFF8G5roI2acw0d3B6JJ9JEkTmXmuARI=; b=UV5gQCT1YW1HA5Bjalt1a/719pg8W6SqtN2q2Othixi8qcANeJwHdCnMbG5LDmgeAZ ObNQe20xRvxXN9UNsFZHdhEyAwHwwxD/pDDiTRD+p4RJEAFq0tENz0mmcVxYXbL9F1/y kkiIMnDPxhCv14C9ueu1yo50EXu0DE4yX2CZ6Il9A+YoG63mEOKDJQc9I0qPZsk/bUcS WygH/6ht4pxt1vAUg+0ahUlx4vREGUqnP8HQil0smkqOudHEDtKX6dtaOwypYkLPD0cE fAgp/ycSo9M25qF5jaSltFawgsxaN1QSGoedubjrsqhD0DBNi+bBg/47Ax1Rl9nAU2l+ n5fg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774987776; x=1775592576; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=FhNqwVSQY4PYFF8G5roI2acw0d3B6JJ9JEkTmXmuARI=; b=CJirC+O4ACyL8s48R6FKpf25DBM9MFAftICzzEmji2CA5Ess+wzZfhXKlr9uLctDZc MpcdOMrUB/y7tQ1a20wWpqY9M7NjYA7YQVlshsGAD5Vb2KeqwH0zh409MeGBoP+r/pDY J/4yFW7MKtnbF2ihOrifGsAS9X1ChV5BBOddmFYP96mLeBBpEA9g7K67LhBb7lJks5hU KYrCurd5N+hLjy5pfQa45JjcghahEgrjcWOVfVqxzzumfFk+AaG3AflxFz/fsfAbPOYR mVzNEnYDMgZnRFMJVTpHkka225fQR6Rj2+Nh32D1NaDn6yj3GFt28+wqyknsHUQxlWLI GF7Q== X-Gm-Message-State: AOJu0Yy9H+wtfkKo7Qmtfc2rB9IcYYUFJs55epoSG4S5BDR6Bpo3uU4x T3eqP9XkV7SmPnrxLDKlVK6tcYxaGkkjvqVt7mOM/wfvBA5WRbE4lRpoqGDnhE+/WPo= X-Gm-Gg: ATEYQzwP/rsSE40XOAk/oPIBQavTFwEQ6F3+1Y17YZeUNnt2ZaMKEzdneDqGqxJDjxS Ca3jj960Bv7I9a6gMFE5Sf5XnlGup5sMh9tlqrLUWJV+1gdoluTQbsLOKyYdteFSq8s1o3ZkSSB d6+/OVnSB8jJ9kQSRrQ0+ImhBOp/39gn2qqoOR4Dja+5sH++Db2BXTRTyU9H9O/EC8KxSAwv/I0 oT4jiuI/04R0EaXIPbCuXoc+wpkIrpyJyuXIFgX/wnyrb8f+t79O1JVg7rJ1lAVkjUdSYyZbYYn Lmpd/Ys5yQPdrH9k2/O8ft2vCjiUGl3n7u6gH+5w9F+3O0cxNxDvNHSjxSEb6Wj2KBCNnQ44X/0 Zx9JE4c5EX6xFj4fNQ0kUh3WjoSQCdRbzXKMKThyulCpjQy0YF/9OuKiKr+S1PRH45fus9F7BI2 1k2V04E7Y= X-Received: by 2002:a05:6808:1909:b0:467:2609:126f with SMTP id 5614622812f47-46ae008269dmr498540b6e.24.1774987776146; Tue, 31 Mar 2026 13:09:36 -0700 (PDT) Received: from 20HS2G4 ([2a09:bac6:bf21:2632::3ce:1f]) by smtp.gmail.com with ESMTPSA id 5614622812f47-46aa03a9179sm6593649b6e.14.2026.03.31.13.09.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 Mar 2026 13:09:34 -0700 (PDT) Date: Tue, 31 Mar 2026 15:09:33 -0500 From: Chris Arges To: Weiming Shi , Eric Dumazet , Paolo Abeni Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com, jgriege@cloudflare.com Subject: [REGRESSION] net: add xmit recursion limit to tunnel xmit functions Message-ID: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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