From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2612030FA4 for ; Wed, 20 Sep 2023 12:20:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E4BEC433C7; Wed, 20 Sep 2023 12:20:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695212427; bh=Cq01sCi9B6NTPpql0haHiVIYmoVmQe8f7I/dHpLSHNE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xb3fDqjd4eEkUl9PTci3rBBPEAC6mDqpLZlXu14V2yFymIDkmGkhxk6BYIVjDAcDq fi6z5jKeSkn6C97X8XoIQdsJ1ZMEfGc5KcvpiTJxENhaU0d9oS4R3YWXh/wrNNGC0J A1RoAN7UuDRln+VOVnr9+Y9vOdAjew8pUIkZDqFA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christophe Leroy , Sasha Levin Subject: [PATCH 4.19 264/273] serial: cpm_uart: Avoid suspicious locking Date: Wed, 20 Sep 2023 13:31:44 +0200 Message-ID: <20230920112854.400913936@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112846.440597133@linuxfoundation.org> References: <20230920112846.440597133@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-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 ad40c75bb58f8..375d4790e058b 100644 --- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c +++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c @@ -1269,19 +1269,14 @@ 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