From nobody Mon Feb 9 03:33:43 2026 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (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 6748820300 for ; Wed, 10 Apr 2024 06:34:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712730856; cv=none; b=qPlLOB2JsBCOB5+nfLdfHDG6+07diYlh42Qq8pDs6tJLZpDyXBq/4cPFgtzqOXVq3lSo9RUZFVXqFMOY3w5GJX4UxJoQrAB5Qv10t6rGKQ1U5lcDMWMwGvRZvPipJ6+d2epBcQmgtCqeQOjX/MCrGvs6CrZwBzvgtoPNuTuMWGw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712730856; c=relaxed/simple; bh=L8qUFpUH7Renm5tiH9WqQL0bEhl/mJAzS7iP1fS8R1U=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=SuaIKXOp7yPo7dU3xGdQY1x8MX6czzk/q9xgJM7GvnY2piqd0+Yokrug5Najg2pH+xKSbN7TDV1uStpm+2Nv6fj5oinYj9od/765HcfGOsKUNjXYjJEOGo4CKgIbzYWgDA7pLZZ1++o89nhdzYsuv4oke5jGr3gv8CfPTWL/6iU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ruRX0-0001d0-MD; Wed, 10 Apr 2024 08:34:02 +0200 Received: from [2a0a:edc0:0:1101:1d::28] (helo=dude02.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ruRWy-00BRRq-U5; Wed, 10 Apr 2024 08:34:00 +0200 Received: from localhost ([::1] helo=dude02.red.stw.pengutronix.de) by dude02.red.stw.pengutronix.de with esmtp (Exim 4.96) (envelope-from ) id 1ruRWy-0057ls-2k; Wed, 10 Apr 2024 08:34:00 +0200 From: Sascha Hauer Date: Wed, 10 Apr 2024 08:33:07 +0200 Subject: [PATCH] tls: defer close to kernel task Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20240410-ktls-defer-close-v1-1-b59e6626b8e4@pengutronix.de> X-B4-Tracking: v=1; b=H4sIAKIyFmYC/x3MwQpAQBCA4VfRnE2NtRSvIgfWLBOhHUlp393m+ B3+/wXlIKzQZi8EvkXl2BOKPAO3DPvMKFMyGDKWbEG4XpvixJ4Duu1QRiLTlLaq7UgNpOwM7OX 5l10f4wdE1IL9YgAAAA== To: Boris Pismenny , John Fastabend , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Paolo Abeni Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Pavel Begunkov , Jens Axboe , kernel@pengutronix.de, Sascha Hauer X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1712730840; l=3347; i=s.hauer@pengutronix.de; s=20230412; h=from:subject:message-id; bh=L8qUFpUH7Renm5tiH9WqQL0bEhl/mJAzS7iP1fS8R1U=; b=ZWLnNgSyiZsCAzmR7gR76h5X3Eps1/swO+Yn89chwI9IWznsIqLFQWRoWpJdGL+f3VBXgiTT7 Jiq7fXS28WAALdd6n/HyKZbwulGDbeoLWiE3Hpq0R45tvv2Rk3niDcl X-Developer-Key: i=s.hauer@pengutronix.de; a=ed25519; pk=4kuc9ocmECiBJKWxYgqyhtZOHj5AWi7+d0n/UjhkwTg= X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: s.hauer@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org proto->close is normally called from a userspace task which can be interrupted by signals. When asynchronous encryption is used then KTLS sends out the final data at close time. When a signal comes in during close then it can happen tcp_sendmsg_locked() is interrupted by that signal while waiting for memory in sk_stream_wait_memory() which then returns with -ERSTARTSYS. It is not possible to recover from this situation and the final transmit data is lost. With this patch we defer the close operation to a kernel task which doesn't get signals. The described situation happens when KTLS is used in conjunction with io_uring, as io_uring uses task_work_add() to add work to the current userspace task. The problem is discussed in [1] and [2] and the solution implemented in this patch is suggested by Pavel Begunkov here [3] [1] https://lore.kernel.org/all/20231010141932.GD3114228@pengutronix.de/ [2] https://lore.kernel.org/all/20240315100159.3898944-1-s.hauer@pengutroni= x.de/ [3] https://lore.kernel.org/all/bfc6afa9-501f-40b6-929a-3aa8c0298265@gmail.= com Signed-off-by: Sascha Hauer --- Note I only need this asynchronous close for the ctx->tx_conf =3D=3D TLS_SW case. I can refactor the patch to only go asynchronous when necessary if that's desired. --- net/tls/tls_main.c | 37 +++++++++++++++++++++++++++++++------ 1 file changed, 31 insertions(+), 6 deletions(-) diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c index b4674f03d71a9..b0b7e0d2f1145 100644 --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -365,16 +365,21 @@ static void tls_sk_proto_cleanup(struct sock *sk, } } =20 -static void tls_sk_proto_close(struct sock *sk, long timeout) +struct tls_close_work { + struct work_struct work; + struct tls_context *ctx; + long timeout; +}; + +static void deferred_close(struct work_struct *work) { + struct tls_close_work *cw =3D container_of(work, struct tls_close_work, w= ork); + struct tls_context *ctx =3D cw->ctx; + struct sock *sk =3D ctx->sk; struct inet_connection_sock *icsk =3D inet_csk(sk); - struct tls_context *ctx =3D tls_get_ctx(sk); long timeo =3D sock_sndtimeo(sk, 0); bool free_ctx; =20 - if (ctx->tx_conf =3D=3D TLS_SW) - tls_sw_cancel_work_tx(ctx); - lock_sock(sk); free_ctx =3D ctx->tx_conf !=3D TLS_HW && ctx->rx_conf !=3D TLS_HW; =20 @@ -395,10 +400,30 @@ static void tls_sk_proto_close(struct sock *sk, long = timeout) tls_sw_strparser_done(ctx); if (ctx->rx_conf =3D=3D TLS_SW) tls_sw_free_ctx_rx(ctx); - ctx->sk_proto->close(sk, timeout); + ctx->sk_proto->close(sk, cw->timeout); =20 if (free_ctx) tls_ctx_free(sk, ctx); + + kfree(cw); +} + +static void tls_sk_proto_close(struct sock *sk, long timeout) +{ + struct tls_context *ctx =3D tls_get_ctx(sk); + struct tls_close_work *cw; + + if (ctx->tx_conf =3D=3D TLS_SW) + tls_sw_cancel_work_tx(ctx); + + cw =3D kmalloc(sizeof(*cw), GFP_KERNEL); + if (!cw) + return; + + INIT_WORK(&cw->work, deferred_close); + cw->timeout =3D timeout; + cw->ctx =3D ctx; + queue_work(system_unbound_wq, &cw->work); } =20 static __poll_t tls_sk_poll(struct file *file, struct socket *sock, --- base-commit: fec50db7033ea478773b159e0e2efb135270e3b7 change-id: 20240410-ktls-defer-close-002934564b09 Best regards, --=20 Sascha Hauer