From patchwork Thu Apr 14 13:13:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 562507 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5094DC433F5 for ; Thu, 14 Apr 2022 13:33:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244842AbiDNNgK (ORCPT ); Thu, 14 Apr 2022 09:36:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57650 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344112AbiDNNa2 (ORCPT ); Thu, 14 Apr 2022 09:30:28 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07F03E6; Thu, 14 Apr 2022 06:28:04 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B233CB82985; Thu, 14 Apr 2022 13:28:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F04E2C385A5; Thu, 14 Apr 2022 13:28:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649942881; bh=qedZ/DiD1BGM2zpjtJoVkqrA0QPzqzuFdcPCJjoXqQI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aJIYbGXlM54feJGx3ymmg9c/MksPwLFA/Nv8LhYvNdeCJ35QIXX7nBQ8ZvVv+ACs0 OMk+c9RSnEhWUTeqlfD39UXrCha7//qhNgPnTYeQ0m78wXBJQZGGz/LXTIM+tBTN3j oJulOgo3ytmDV1Wg6158xq7hcyLRpK65WffoWMak= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Abraham , Kyungmin Park , Hyeonkook Kim , Jiri Slaby , Sasha Levin Subject: [PATCH 4.19 296/338] serial: samsung_tty: do not unlock port->lock for uart_write_wakeup() Date: Thu, 14 Apr 2022 15:13:19 +0200 Message-Id: <20220414110847.311340500@linuxfoundation.org> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220414110838.883074566@linuxfoundation.org> References: <20220414110838.883074566@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jiri Slaby [ Upstream commit 988c7c00691008ea1daaa1235680a0da49dab4e8 ] The commit c15c3747ee32 (serial: samsung: fix potential soft lockup during uart write) added an unlock of port->lock before uart_write_wakeup() and a lock after it. It was always problematic to write data from tty_ldisc_ops::write_wakeup and it was even documented that way. We fixed the line disciplines to conform to this recently. So if there is still a missed one, we should fix them instead of this workaround. On the top of that, s3c24xx_serial_tx_dma_complete() in this driver still holds the port->lock while calling uart_write_wakeup(). So revert the wrap added by the commit above. Cc: Thomas Abraham Cc: Kyungmin Park Cc: Hyeonkook Kim Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220308115153.4225-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/samsung.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index 1528a7ba2bf4..49661cef5469 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -761,11 +761,8 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id) goto out; } - if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) { - spin_unlock(&port->lock); + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); - spin_lock(&port->lock); - } if (uart_circ_empty(xmit)) s3c24xx_serial_stop_tx(port);