From patchwork Tue Sep 15 18:56:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: patricia.domingues@canonical.com X-Patchwork-Id: 1364592 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4BrXYk3DQLz9sVB; Wed, 16 Sep 2020 04:58:18 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1kIG9e-0000MW-Aq; Tue, 15 Sep 2020 18:58:14 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kIG9d-0000MN-4W for kernel-team@lists.ubuntu.com; Tue, 15 Sep 2020 18:58:13 +0000 Received: from 1.general.patriciasd.us.vpn ([10.172.64.192] helo=localhost.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kIG9c-0001Qu-5Q for kernel-team@lists.ubuntu.com; Tue, 15 Sep 2020 18:58:12 +0000 From: patricia.domingues@canonical.com To: kernel-team@lists.ubuntu.com Subject: [SRU][X][B][F][G][PATCH 1/1] tty: hvcs: Don't NULL tty->driver_data until hvcs_cleanup() Date: Tue, 15 Sep 2020 15:56:49 -0300 Message-Id: <20200915185649.24706-2-patricia.domingues@canonical.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200915185649.24706-1-patricia.domingues@canonical.com> References: <20200915185649.24706-1-patricia.domingues@canonical.com> X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Tyrel Datwyler BugLink: https://bugs.launchpad.net/bugs/1892546 The code currently NULLs tty->driver_data in hvcs_close() with the intent of informing the next call to hvcs_open() that device needs to be reconfigured. However, when hvcs_cleanup() is called we copy hvcsd from tty->driver_data which was previoulsy NULLed by hvcs_close() and our call to tty_port_put(&hvcsd->port) doesn't actually do anything since &hvcsd->port ends up translating to NULL by chance. This has the side effect that when hvcs_remove() is called we have one too many port references preventing hvcs_destuct_port() from ever being called. This also prevents us from reusing the /dev/hvcsX node in a future hvcs_probe() and we can eventually run out of /dev/hvcsX devices. Fix this by waiting to NULL tty->driver_data in hvcs_cleanup(). Fixes: 27bf7c43a19c ("TTY: hvcs, add tty install") Signed-off-by: Tyrel Datwyler Link: https://lore.kernel.org/r/20200820234643.70412-1-tyreld@linux.ibm.com Signed-off-by: Greg Kroah-Hartman (cherry picked from commit 63ffcbdad738e3d1c857027789a2273df3337624) Signed-off-by: Patricia Domingues Acked-by: Kleber Sacilotto de Souza --- drivers/tty/hvc/hvcs.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c index 5997b1731111..cba662c50f91 100644 --- a/drivers/tty/hvc/hvcs.c +++ b/drivers/tty/hvc/hvcs.c @@ -1232,13 +1232,6 @@ static void hvcs_close(struct tty_struct *tty, struct file *filp) tty_wait_until_sent(tty, HVCS_CLOSE_WAIT); - /* - * This line is important because it tells hvcs_open that this - * device needs to be re-configured the next time hvcs_open is - * called. - */ - tty->driver_data = NULL; - free_irq(irq, hvcsd); return; } else if (hvcsd->port.count < 0) { @@ -1254,6 +1247,13 @@ static void hvcs_cleanup(struct tty_struct * tty) { struct hvcs_struct *hvcsd = tty->driver_data; + /* + * This line is important because it tells hvcs_open that this + * device needs to be re-configured the next time hvcs_open is + * called. + */ + tty->driver_data = NULL; + tty_port_put(&hvcsd->port); }