From patchwork Thu Apr 14 13:13:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 562256 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 42BB6C433F5 for ; Thu, 14 Apr 2022 14:03:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238001AbiDNOFq (ORCPT ); Thu, 14 Apr 2022 10:05:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347297AbiDNN6o (ORCPT ); Thu, 14 Apr 2022 09:58:44 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8F5118385; Thu, 14 Apr 2022 06:49:23 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 188B661D29; Thu, 14 Apr 2022 13:49:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29A34C385A1; Thu, 14 Apr 2022 13:49:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649944162; bh=leA5SjVEI+OFdMEEiqCpgxxL7VQwPeWyvqNgqzEKnOs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yKGdTCNRLDccHF1FSyS7JW2CuHlPmBiKkCSnvbGBMKgfwLjm6TKmG+0a6B5wXl472 chuNPTeW0GACoFttFuEMySb32QwIpfN9q4hgG+/a18czoZVVqSwXaYPuRqnQrARskd uKRjXfKPjag3rbM1Ot/S3RpFzNuWBTgxyJBnKPWc= 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 5.4 416/475] serial: samsung_tty: do not unlock port->lock for uart_write_wakeup() Date: Thu, 14 Apr 2022 15:13:21 +0200 Message-Id: <20220414110906.705000925@linuxfoundation.org> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220414110855.141582785@linuxfoundation.org> References: <20220414110855.141582785@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 c7683beb3412..6040d5a6139a 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);