From patchwork Tue Apr 12 06:29:39 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: 560759 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 2CE08C4332F for ; Tue, 12 Apr 2022 06:43:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350500AbiDLGpl (ORCPT ); Tue, 12 Apr 2022 02:45:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350835AbiDLGn1 (ORCPT ); Tue, 12 Apr 2022 02:43:27 -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 D3341381B0; Mon, 11 Apr 2022 23:36:50 -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 44AA2618C8; Tue, 12 Apr 2022 06:36:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56848C385A1; Tue, 12 Apr 2022 06:36:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649745409; bh=rma41m+xS7wxqcblXcOKWTwihmSCb05KPyPCQ5lDTtI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DXmGJlHU7+MNRQKQDk/P+Idj6eLpToWojz8ycj0oI+zvYyywl+2i1NSbC99gdfxlK JylSyb/4hF6tfkrJCnHnWtbXPhMmCQHd4X/tDPdo+LeGsMRT1taXl9IHff65wadKX2 M0z+6PqndJzdCx+oFQt4KfjNpN+encwMVFcBZXO8= 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 5.10 088/171] serial: samsung_tty: do not unlock port->lock for uart_write_wakeup() Date: Tue, 12 Apr 2022 08:29:39 +0200 Message-Id: <20220412062930.432670587@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062927.870347203@linuxfoundation.org> References: <20220412062927.870347203@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_tty.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c index 8ae3e03fbd8c..81faead3c4f8 100644 --- a/drivers/tty/serial/samsung_tty.c +++ b/drivers/tty/serial/samsung_tty.c @@ -883,11 +883,8 @@ 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);