From patchwork Tue Oct 27 13:48:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 290114 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=-12.8 required=3.0 tests=BAYES_00,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=ham 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 E3604C55179 for ; Tue, 27 Oct 2020 14:12:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC32C22202 for ; Tue, 27 Oct 2020 14:12:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603807936; bh=l8K4TD6xszqs05CgqhSK96Mtk0Jyenp1xZxIL67tMP4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JrDBXUQXw5h61AwoLShtKJpuuYPdysXd+WPrhqleIPBB0tYxQVd1+u5IvbGRDOqEN xT72X209KY+g3EGNhAO2PYOnjXX0+ojotZZx2cTS897tfbEeqZYgYmFw7daoiG/G/b Ki3wQKpyoaIrdnuiXernted8u3S/Vzk9UIdEfWrg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756257AbgJ0OMP (ORCPT ); Tue, 27 Oct 2020 10:12:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:59392 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755582AbgJ0OKa (ORCPT ); Tue, 27 Oct 2020 10:10:30 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 31D2C2072D; Tue, 27 Oct 2020 14:10:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603807829; bh=l8K4TD6xszqs05CgqhSK96Mtk0Jyenp1xZxIL67tMP4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TWJ6i/MYI1ua0jTY/6Y72aV13s6Hwh+ugrrETomstL37TXZDX4Jr547G37Xnmg54B QEs9KdHhTAJM9ls3AsVVDlDOZ2KJqFacWiAmLLvarEfzIag/XnRPPePwB0isJjOtA/ Da1W1Z+kapdVnBvZ94bFI/Ct3NqySkZnIVSwM1Zo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tyrel Datwyler , Sasha Levin Subject: [PATCH 4.14 056/191] tty: hvcs: Dont NULL tty->driver_data until hvcs_cleanup() Date: Tue, 27 Oct 2020 14:48:31 +0100 Message-Id: <20201027134912.428757015@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027134909.701581493@linuxfoundation.org> References: <20201027134909.701581493@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tyrel Datwyler [ Upstream commit 63ffcbdad738e3d1c857027789a2273df3337624 ] 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 Signed-off-by: Sasha Levin --- 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 63c29fe9d21f1..f77d7f39c113c 100644 --- a/drivers/tty/hvc/hvcs.c +++ b/drivers/tty/hvc/hvcs.c @@ -1231,13 +1231,6 @@ 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) { @@ -1252,6 +1245,13 @@ 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); }