From patchwork Thu Aug 3 13:56:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 710794 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 4219BEB64DD for ; Thu, 3 Aug 2023 14:20:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235906AbjHCOUV (ORCPT ); Thu, 3 Aug 2023 10:20:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235913AbjHCOUU (ORCPT ); Thu, 3 Aug 2023 10:20:20 -0400 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0978011B; Thu, 3 Aug 2023 07:20:18 -0700 (PDT) Received: from localhost (mailhub3.si.c-s.fr [192.168.12.233]) by localhost (Postfix) with ESMTP id 4RGr4c1Jw0z9t3S; 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Thu, 3 Aug 2023 15:56:57 +0200 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 373Duv1P494160; Thu, 3 Aug 2023 15:56:57 +0200 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Greg Kroah-Hartman , Jiri Slaby , Michael Ellerman , Nicholas Piggin , Timur Tabi Cc: Christophe Leroy , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-serial@vger.kernel.org Subject: [PATCH v1 01/12] serial: cpm_uart: Avoid suspicious locking Date: Thu, 3 Aug 2023 15:56:42 +0200 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1691071000; l=2066; i=christophe.leroy@csgroup.eu; s=20211009; h=from:subject:message-id; bh=g1/VJfSY6urnYolQkf6XjuqARyJIyQnB+2i32ZVNAL8=; b=ox36XmAYX8W9jeRLvNG7fKCBBZNkkZiraAKzbwxaL6IRb4RnMjidksKybn8nHV7gQhBFVWUS2 KtQcpca72eOB3BTBWKygA/DrIogB5ilpy3rzlEEst3AvHs/emqviZtG X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org 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 --- 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 66afa9bea6bf..71366a4cea22 100644 --- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c +++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c @@ -1255,19 +1255,14 @@ 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); } }