From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8447CC10F27 for ; Tue, 10 Mar 2020 13:11:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52F31208E4 for ; Tue, 10 Mar 2020 13:11:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583845897; bh=1Ab1FCoddUe1BX9XPSIJ0DoL+dXn+oXOQ+sECh6PTO0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=NiKIuMmv0qutRODrRJIRZ0KFI90c8uYBsFEVDFQ3wtCAU7oPSx3gK69AHvyf3eFmM +Jic4LHnPLxISEvNYXE9vgV0L7JEuQA2zUc1SWWeSDe7xcHtbCxJ0WeF0ibVbEqGz6 xHsLYw6bO6Korz/OsH3OotcmX5yoUubxQSKMtt3A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731449AbgCJNLg (ORCPT ); Tue, 10 Mar 2020 09:11:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:33096 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730887AbgCJNLc (ORCPT ); Tue, 10 Mar 2020 09:11:32 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 98E9B208E4; Tue, 10 Mar 2020 13:11:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583845892; bh=1Ab1FCoddUe1BX9XPSIJ0DoL+dXn+oXOQ+sECh6PTO0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N/1KLIKNIaBHdNgx9wSw7+XBrgWB8NFamn2EMV2WH2Da3nJkiqJFo5F9Zb+WfG3DW f2TuM4pW/V9ch5SUg1lwx0koovXpljqB8arGr479/SAC6R0BTe88wi64PZ/vsSD7Dl yNIlgyisG0JHmKbsZqCbXupHZVLsGlRHNt+GBHNQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sergey Organov , =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= , Felipe Balbi , Sasha Levin Subject: [PATCH 4.19 12/86] usb: gadget: serial: fix Tx stall after buffer overflow Date: Tue, 10 Mar 2020 13:44:36 +0100 Message-Id: <20200310124531.459641903@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200310124530.808338541@linuxfoundation.org> References: <20200310124530.808338541@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sergey Organov [ Upstream commit e4bfded56cf39b8d02733c1e6ef546b97961e18a ] Symptom: application opens /dev/ttyGS0 and starts sending (writing) to it while either USB cable is not connected, or nobody listens on the other side of the cable. If driver circular buffer overflows before connection is established, no data will be written to the USB layer until/unless /dev/ttyGS0 is closed and re-opened again by the application (the latter besides having no means of being notified about the event of establishing of the connection.) Fix: on open and/or connect, kick Tx to flush circular buffer data to USB layer. Signed-off-by: Sergey Organov Reviewed-by: Michał Mirosław Signed-off-by: Felipe Balbi Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/u_serial.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index d4d317db89df5..38afe96c5cd26 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -567,8 +567,10 @@ static int gs_start_io(struct gs_port *port) port->n_read = 0; started = gs_start_rx(port); - /* unblock any pending writes into our circular buffer */ if (started) { + gs_start_tx(port); + /* Unblock any pending writes into our circular buffer, in case + * we didn't in gs_start_tx() */ tty_wakeup(port->port.tty); } else { gs_free_requests(ep, head, &port->read_allocated); -- 2.20.1