From nobody Sun Sep 20 16:45:32 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 45395411FA3; Mon, 3 Aug 2026 16:17:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785773841; cv=none; b=m/mTwQVvc87kGAZa+vl+j1q+mEBu4/ub1StOoyPVBRcxUXSsDUFlf3d44stcPjmVPDm2fgqAX7sXqGo6tnbzJ+vZ13p+iwZPQtXPNZr5cUyWwPF9KvTmPoODMtZ3ggi22iH8ngDQEcGXnojjY5HTiBdlavNys6bSXq3zyiEKWaU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785773841; c=relaxed/simple; bh=2LCtQYaFHMYShjE0L774cau909DKU6IxvzHD3daSzt8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=BjeVjHgNKbQuGIvYls2TrHLXbkMdjNaawEmO9vxyrAm7T03dSu+Fn5JfQiCv2m/QNKqheA73e5pQJxFiWXJjQa9RBTT4pvRSk80P41nkXKC7UwMoypYsyjfvFJ7mo5R2/Nv2e0h6FjkkgggG/fSv+UjOHFtmQYBaXAk1rEoDlAY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZXb5lbk3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZXb5lbk3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC3F31F000E9; Mon, 3 Aug 2026 16:17:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785773839; bh=CHz7hPGcuGQaXXaAvcxIgvtwBW6pE1qWtUMNAIp/Hpw=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=ZXb5lbk3U2Cm5cd/gEH44ystsRNdr1zre2oUmXbG8QEnqE77841Z857R3YWC3pDg7 B0tAEJeDTt5/7fBYcPRUdixNKbpkdYDPURnHy4di3jGnJFEUKn76O9+7TMWW4HEuZb CIdAjNFxYNcRfshGef/LJhbDJYjGABYPxxyNYwRZ46hkUd6mmX0NumNP+ao8AfP1zB m22e0F1SYV/dNPL9HBtAZjJSs/h82zlSJqvsNxs7iIEpZ+ivHNBUKxt38Q0EGPAyCr LIyGuSxC04oEveYZQYSuGPLe9JWR9NWGvtzhc0DitPGwlvwuJRApcFoXHy3U+8AzCi RmVVELdv/zbJw== From: "Matthieu Baerts (NGI0)" Date: Mon, 03 Aug 2026 18:16:40 +0200 Subject: [PATCH net v2 8/8] mptcp: reclaim forward-allocated memory on RX path errors Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260803-net-mptcp-misc-fixes-7-2-rc6-v2-8-b8f496d71664@kernel.org> References: <20260803-net-mptcp-misc-fixes-7-2-rc6-v2-0-b8f496d71664@kernel.org> In-Reply-To: <20260803-net-mptcp-misc-fixes-7-2-rc6-v2-0-b8f496d71664@kernel.org> To: Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman Cc: netdev@vger.kernel.org, mptcp@lists.linux.dev, linux-kernel@vger.kernel.org, "Matthieu Baerts (NGI0)" , stable@vger.kernel.org X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1341; i=matttbe@kernel.org; h=from:subject:message-id; bh=13ycqCYB6Icqk3NK7EG0GaWaP44YW7kNbjVu5JUlTgc=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGLIK9n2RaFxZbX1qsdwdSfa7ps8W371q1Kye9mfeCt+mS 1+299cs7yhlYRDjYpAVU2SRbovMn/m8irfEy88CZg4rE8gQBi5OAZiI1WZGhm7LDVtfKlxxmz6x 9lJHaMlmfjXmK4s5LMvtero0TnH/cGb4X7v3tuWJ640GO56uZIqtPfd0cvjh3ws3bpE/oraoYfb 0r9wA X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 From: Paolo Abeni After commit 9db5b3cec4ec ("mptcp: borrow forward memory from subflow"), errors in the receive path prior to queueing skbs into the receive queue do not trigger forward-allocated memory reclaiming. Prevent forward memory from growing unboundedly in pathological drop scenarios by explicitly reclaiming memory when skbs are dropped. Fixes: 9db5b3cec4ec ("mptcp: borrow forward memory from subflow") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) --- v2: Start comment on the same line as the opening /*, like in most places in the code. (Clashiko) --- net/mptcp/protocol.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index ca644ec53eed..7c8180d8d5ef 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -149,6 +149,12 @@ struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk) =20 static void mptcp_drop(struct sock *sk, struct sk_buff *skb) { + /* The skb forward memory was already transferred to sk by + * mptcp_borrow_fwdmem(), even before setting the destructor. + */ + if (!skb->destructor) + sk_mem_reclaim(sk); + sk_drops_skbadd(sk, skb); __kfree_skb(skb); } --=20 2.53.0