From mboxrd@z Thu Jan 1 00:00:00 1970 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 9061DCE79CF for ; Wed, 20 Sep 2023 12:42:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236246AbjITMmO (ORCPT ); Wed, 20 Sep 2023 08:42:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236255AbjITMmN (ORCPT ); Wed, 20 Sep 2023 08:42:13 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC13A9E for ; Wed, 20 Sep 2023 05:42:07 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33696C433C8; Wed, 20 Sep 2023 12:42:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695213727; bh=Vxl0vpbnLmvYPcwQQdhAcimMr1M3skkvMmvCwyeeWKs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MNJIVJT1uFOJMtxdNah/y7OrK4j0OjcNosUire2TUZ6klR+C3wKE70j8/IqwMS1pk Uv2d48xLwXJHO7F4FrJNQH0AQmAzQbVBYsWzaIbu5wgm3xoTwP+rNkFKVCWAkgaZhD KmwSLZchV+LPTtNbVafLLS8du6K62b9vld1Ugdcg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christophe Leroy , Sasha Levin Subject: [PATCH 5.4 343/367] serial: cpm_uart: Avoid suspicious locking Date: Wed, 20 Sep 2023 13:32:00 +0200 Message-ID: <20230920112907.384811576@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112858.471730572@linuxfoundation.org> References: <20230920112858.471730572@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christophe Leroy [ Upstream commit 36ef11d311f405e55ad8e848c19b212ff71ef536 ] CHECK drivers/tty/serial/cpm_uart/cpm_uart_core.c drivers/tty/serial/cpm_uart/cpm_uart_core.c:1271:39: warning: context imbalance in 'cpm_uart_console_write' - unexpected unlock Allthough 'nolock' is not expected to change, sparse find the following form suspicious: if (unlikely(nolock)) { local_irq_save(flags); } else { spin_lock_irqsave(&pinfo->port.lock, flags); } cpm_uart_early_write(pinfo, s, count, true); if (unlikely(nolock)) { local_irq_restore(flags); } else { spin_unlock_irqrestore(&pinfo->port.lock, flags); } Rewrite it a more obvious form: if (unlikely(oops_in_progress)) { local_irq_save(flags); cpm_uart_early_write(pinfo, s, count, true); local_irq_restore(flags); } else { spin_lock_irqsave(&pinfo->port.lock, flags); cpm_uart_early_write(pinfo, s, count, true); spin_unlock_irqrestore(&pinfo->port.lock, flags); } Signed-off-by: Christophe Leroy Link: https://lore.kernel.org/r/f7da5cdc9287960185829cfef681a7d8614efa1f.1691068700.git.christophe.leroy@csgroup.eu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/cpm_uart/cpm_uart_core.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/cpm_uart/cpm_uart_core.c b/drivers/tty/serial/cpm_uart/cpm_uart_core.c index de6d02f7abe2b..c37036fee231d 100644 --- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c +++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c @@ -1267,19 +1267,14 @@ static void cpm_uart_console_write(struct console *co, const char *s, { struct uart_cpm_port *pinfo = &cpm_uart_ports[co->index]; unsigned long flags; - int nolock = oops_in_progress; - if (unlikely(nolock)) { + if (unlikely(oops_in_progress)) { local_irq_save(flags); - } else { - spin_lock_irqsave(&pinfo->port.lock, flags); - } - - cpm_uart_early_write(pinfo, s, count, true); - - if (unlikely(nolock)) { + cpm_uart_early_write(pinfo, s, count, true); local_irq_restore(flags); } else { + spin_lock_irqsave(&pinfo->port.lock, flags); + cpm_uart_early_write(pinfo, s, count, true); spin_unlock_irqrestore(&pinfo->port.lock, flags); } } -- 2.40.1