From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 2940F24C82 for ; Tue, 10 Oct 2023 14:19:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [IPv6:2a0a:edc0:2:b01:1d::104]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF78CB6 for ; Tue, 10 Oct 2023 07:19:41 -0700 (PDT) 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 1qqDa8-0005FO-NP; Tue, 10 Oct 2023 16:19:32 +0200 Received: from [2a0a:edc0:2:b01:1d::c0] (helo=ptx.whiteo.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 1qqDa8-000gWG-7a; Tue, 10 Oct 2023 16:19:32 +0200 Received: from sha by ptx.whiteo.stw.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1qqDa8-00Dktd-3i; Tue, 10 Oct 2023 16:19:32 +0200 Date: Tue, 10 Oct 2023 16:19:32 +0200 To: Jens Axboe Cc: Pavel Begunkov , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, Boris Pismenny , John Fastabend , Jakub Kicinski , netdev@vger.kernel.org Subject: Problem with io_uring splice and KTLS Message-ID: <20231010141932.GD3114228@pengutronix.de> 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 X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain User-Agent: Mutt/1.10.1 (2018-07-13) From: Sascha Hauer X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Hi, I am working with a webserver using io_uring in conjunction with KTLS. The webserver basically splices static file data from a pipe to a socket which uses KTLS for encryption. When splice is done the socket is closed. This works fine when using software encryption in KTLS. Things go awry though when the software encryption is replaced with the CAAM driver which replaces the synchronous encryption with a asynchronous queue/interrupt/completion flow. So far I have traced it down to tls_push_sg() calling tcp_sendmsg_locked() to send the completed encrypted messages. tcp_sendmsg_locked() sometimes waits for more memory on the socket by calling sk_stream_wait_memory(). This in turn returns -ERESTARTSYS due to: if (signal_pending(current)) goto do_interrupted; The current task has the TIF_NOTIFY_SIGNAL set due to: io_req_normal_work_add() { ... /* This interrupts sk_stream_wait_memory() (notify_method == TWA_SIGNAL) */ task_work_add(req->task, &tctx->task_work, ctx->notify_method))) } The call stack when sk_stream_wait_memory() fails is as follows: [ 1385.428816] dump_backtrace+0xa0/0x128 [ 1385.432568] show_stack+0x20/0x38 [ 1385.435878] dump_stack_lvl+0x48/0x60 [ 1385.439539] dump_stack+0x18/0x28 [ 1385.442850] tls_push_sg+0x100/0x238 [ 1385.446424] tls_tx_records+0x118/0x1d8 [ 1385.450257] tls_sw_release_resources_tx+0x74/0x1a0 [ 1385.455135] tls_sk_proto_close+0x2f8/0x3f0 [ 1385.459315] inet_release+0x58/0xb8 [ 1385.462802] inet6_release+0x3c/0x60 [ 1385.466374] __sock_release+0x48/0xc8 [ 1385.470035] sock_close+0x20/0x38 [ 1385.473347] __fput+0xbc/0x280 [ 1385.476399] ____fput+0x18/0x30 [ 1385.479537] task_work_run+0x80/0xe0 [ 1385.483108] io_run_task_work+0x40/0x108 [ 1385.487029] __arm64_sys_io_uring_enter+0x164/0xad8 [ 1385.491907] invoke_syscall+0x50/0x128 [ 1385.495655] el0_svc_common.constprop.0+0x48/0xf0 [ 1385.500359] do_el0_svc_compat+0x24/0x40 [ 1385.504279] el0_svc_compat+0x38/0x108 [ 1385.508026] el0t_32_sync_handler+0x98/0x140 [ 1385.512294] el0t_32_sync+0x194/0x198 So the socket is being closed and KTLS tries to send out the remaining completed messages. From a splice point of view everything has been sent successfully, but not everything made it through KTLS to the socket and the remaining data is sent while closing the socket. I vaguely understand what's going on here, but I haven't got the slightest idea what to do about this. Any ideas? Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |