From: Jaidev Shastri via B4 Relay <devnull+jaidevshastri.vt.edu@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>,
Michal Simek <michal.simek@amd.com>
Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Jaidev Shastri <jaidevshastri@vt.edu>
Subject: [PATCH] serial: xilinx_uartps: publish console_port with release semantics
Date: Mon, 21 Sep 2026 21:21:13 -0400 [thread overview]
Message-ID: <20260921-mb-uartps-v1-1-9fc2f3d4b1a5@vt.edu> (raw)
From: Jaidev Shastri <jaidevshastri@vt.edu>
cdns_uart_probe() assigns the first probed port to console_port with a
plain store once the port is set up. cdns_uart_console_write() and
cdns_uart_console_setup() read it with plain loads.
Store it with smp_store_release() and read it with smp_load_acquire().
Found with MBCheck, a static herd7-based memory consistency checker.
Signed-off-by: Jaidev Shastri <jaidevshastri@vt.edu>
---
drivers/tty/serial/xilinx_uartps.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index a072b75db..59e0d388d 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1371,7 +1371,8 @@ static struct uart_port *console_port;
static void cdns_uart_console_write(struct console *co, const char *s,
unsigned int count)
{
- struct uart_port *port = console_port;
+ /* Pairs with the smp_store_release() in cdns_uart_probe(). */
+ struct uart_port *port = smp_load_acquire(&console_port);
unsigned long flags;
unsigned int imr, ctrl;
int locked = 1;
@@ -1414,7 +1415,8 @@ static void cdns_uart_console_write(struct console *co, const char *s,
*/
static int cdns_uart_console_setup(struct console *co, char *options)
{
- struct uart_port *port = console_port;
+ /* Pairs with the smp_store_release() in cdns_uart_probe(). */
+ struct uart_port *port = smp_load_acquire(&console_port);
int baud = 9600;
int bits = 8;
@@ -1812,7 +1814,8 @@ static int cdns_uart_probe(struct platform_device *pdev)
*/
if (!console_port) {
cdns_uart_console.index = id;
- console_port = port;
+ /* Pairs with the smp_load_acquire() in the console callbacks. */
+ smp_store_release(&console_port, port);
}
#endif
if (cdns_uart_data->port->rs485.flags & SER_RS485_ENABLED)
---
base-commit: 93f51579e7df248780214094418f205253383cc5
change-id: 20260921-mb-uartps-ce1b1ca29a83
Best regards,
--
Jaidev Shastri <jaidevshastri@vt.edu>
next reply other threads:[~2026-09-22 1:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 1:21 Jaidev Shastri via B4 Relay [this message]
2026-09-23 12:08 ` Greg Kroah-Hartman
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