From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8C23D21D3C5; Tue, 2 Dec 2025 19:08:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764702488; cv=none; b=b81zOGDYQlm1/C/seu8Evxg5NahquMCRA7G9glb0Yn9clWHS+wOa7JMSySyPYtQZxqFgz8A2lmXoPiMmQew1paoojk0fmeDG+obJ78HUkatJvn1aUvRzYyFe7VbiALAxcOFYxMyc9yLgwiCaaFrkWKmmhvC2/fdZ1CFsTmwtgxo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764702488; c=relaxed/simple; bh=qzF6qpnCYLfLMh/GEXQ0ExYLuCvljL6XKotj2oFdnBE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Y2vKdHg5/ah21cVQGx/yLZClfjZwk3p+qzr//KYQql4GsCpQ3VTU9vUNe02sBhvlrvX93461qtkyjoe8Dn3ofV0r4tJ4bCIsmf5skmot3LQ00SoVx0YAwJGCeiZcD3A6CU/GmhC5jwGxTYGAbHUVkFE5SgLimOClQX/0JdYzeOY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SkSvLBRE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SkSvLBRE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87F46C4CEF1; Tue, 2 Dec 2025 19:08:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764702487; bh=qzF6qpnCYLfLMh/GEXQ0ExYLuCvljL6XKotj2oFdnBE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=SkSvLBREnRcZrNhP9XyGgIseNO+qMt4yRTev6PRVBjxYy9xmtLcq2FUdqxYgMOGkK 4u5VgOcEki8jvh1rxFw8tWOZJPJVnEr93/sdYMFSK15ShWtytOJR1/Rfqf7QxfKNR1 /11zxPxEL/pJetGsUgyBeb9wiUl3TJz/j1pYNLGQDiCnHUslQnvHL6SaoBdF+9Ufzi SiZ3CCiyVcTaSN9fkA8HZ2lU+Dce3JKdzBvSstDnW86QT9KnTOBg04lgZMqUmX8ewi 5WQkmc5Sf6bby8yhbDuMaX6GJ2TxM4wNGtcUAzlozw+0O1CurZ175660uO4Elqod4P oXZ9UH7d2b9Pg== Date: Tue, 2 Dec 2025 11:08:05 -0800 From: Jakub Kicinski To: Mikhail Lobanov Cc: "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , David Bauer , James Chapman , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, lvc-project@linuxtesting.org Subject: Re: [PATCH net-next v6] l2tp: fix double dst_release() on sk_dst_cache race Message-ID: <20251202110805.765fa71d@kernel.org> In-Reply-To: <20251202180545.18974-1-m.lobanov@rosa.ru> References: <20251202180545.18974-1-m.lobanov@rosa.ru> 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-Transfer-Encoding: 7bit On Tue, 2 Dec 2025 21:05:43 +0300 Mikhail Lobanov wrote: > A reproducible rcuref - imbalanced put() warning is observed under > IPv6 L2TP (pppol2tp) traffic with blackhole routes, indicating an > imbalance in dst reference counting for routes cached in > sk->sk_dst_cache and pointing to a subtle lifetime/synchronization > issue between the helpers that validate and drop cached dst entries. Breaks allmodconfig build: ERROR: modpost: "ip_options_build" [net/l2tp/l2tp_core.ko] undefined! Please note that net-next is closed for the duration of the merge window. If you want to repost this (after waiting the customary 24h) please do so as an RFC. -- pw-bot: cr