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 C945027F34 for ; Fri, 21 Jul 2023 19:05:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4790CC433C8; Fri, 21 Jul 2023 19:05:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689966352; bh=IT4g9tmBPoY8YV40W/F8oLhCHzK5qZea8NXwewSCheE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kfNHYGYc9lo4tAvzVMjidZ/7nsNCQTXU3pKFoi59N9yJ//Hs4B+Q/ZI6vOJq3AvVH 8JeF67mdSrJE1U6rnGixXByBXGVvRTJNLLbPEmEU2L+t6dioNnk+QvxasWWeF7t/ws +WwXviHd9KjPdOrGYsA0Pij6Sesy2Sb0VA57bQXo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, John Ogness , Tony Lindgren , Sasha Levin Subject: [PATCH 5.15 286/532] serial: 8250: lock port for UART_IER access in omap8250_irq() Date: Fri, 21 Jul 2023 18:03:10 +0200 Message-ID: <20230721160629.935749549@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160614.695323302@linuxfoundation.org> References: <20230721160614.695323302@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: John Ogness [ Upstream commit 25614735a647693c1260f253dc3ab32127697806 ] omap8250_irq() accesses UART_IER. This register is modified twice by each console write (serial8250_console_write()) under the port lock. omap8250_irq() must also take the port lock to guanentee synchronized access to UART_IER. Since the port lock is already being taken for the stop_rx() callback and since it is safe to call cancel_delayed_work() while holding the port lock, simply extend the port lock region to include UART_IER access. Fixes: 1fe0e1fa3209 ("serial: 8250_omap: Handle optional overrun-throttle-ms property") Signed-off-by: John Ogness Reviewed-by: Tony Lindgren Link: https://lore.kernel.org/r/20230525093159.223817-8-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/8250/8250_omap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index 28e243312286f..de0447c87846b 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -653,17 +653,18 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id) if ((lsr & UART_LSR_OE) && up->overrun_backoff_time_ms > 0) { unsigned long delay; + /* Synchronize UART_IER access against the console. */ + spin_lock(&port->lock); up->ier = port->serial_in(port, UART_IER); if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) { - spin_lock(&port->lock); port->ops->stop_rx(port); - spin_unlock(&port->lock); } else { /* Keep restarting the timer until * the input overrun subsides. */ cancel_delayed_work(&up->overrun_backoff); } + spin_unlock(&port->lock); delay = msecs_to_jiffies(up->overrun_backoff_time_ms); schedule_delayed_work(&up->overrun_backoff, delay); -- 2.39.2