The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e0a851fe6b9b619527bd928aa93caaddd003f70c Mon Sep 17 00:00:00 2001
From: Lukas Wunner <lukas@xxxxxxxxx>
Date: Tue, 12 May 2020 14:40:01 +0200
Subject: [PATCH] serial: 8250: Avoid error message on reprobe
If the call to uart_add_one_port() in serial8250_register_8250_port()
fails, a half-initialized entry in the serial_8250ports[] array is left
behind.
A subsequent reprobe of the same serial port causes that entry to be
reused. Because uart->port.dev is set, uart_remove_one_port() is called
for the half-initialized entry and bails out with an error message:
bcm2835-aux-uart 3f215040.serial: Removing wrong port: (null) != (ptrval)
The same happens on failure of mctrl_gpio_init() since commit
4a96895f74c9 ("tty/serial/8250: use mctrl_gpio helpers").
Fix by zeroing the uart->port.dev pointer in the probe error path.
The bug was introduced in v2.6.10 by historical commit befff6f5bf5f
("[SERIAL] Add new port registration/unregistration functions."):
https://git.kernel.org/tglx/history/c/befff6f5bf5f
The commit added an unconditional call to uart_remove_one_port() in
serial8250_register_port(). In v3.7, commit 835d844d1a28 ("8250_pnp:
do pnp probe before legacy probe") made that call conditional on
uart->port.dev which allows me to fix the issue by zeroing that pointer
in the error path. Thus, the present commit will fix the problem as far
back as v3.7 whereas still older versions need to also cherry-pick
835d844d1a28.
Fixes: 835d844d1a28 ("8250_pnp: do pnp probe before legacy probe")
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v2.6.10
Cc: stable@xxxxxxxxxxxxxxx # v2.6.10: 835d844d1a28: 8250_pnp: do pnp probe before legacy
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/b4a072013ee1a1d13ee06b4325afb19bda57ca1b.1589285873.git.lukas@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 45d9117cab68..9548d3f8fc8e 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1040,7 +1040,7 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
gpios = mctrl_gpio_init(&uart->port, 0);
if (IS_ERR(gpios)) {
ret = PTR_ERR(gpios);
- goto out_unlock;
+ goto err;
} else {
uart->gpios = gpios;
}
@@ -1089,8 +1089,10 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
serial8250_apply_quirks(uart);
ret = uart_add_one_port(&serial8250_reg,
&uart->port);
- if (ret == 0)
- ret = uart->port.line;
+ if (ret)
+ goto err;
+
+ ret = uart->port.line;
} else {
dev_info(uart->port.dev,
"skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
@@ -1112,10 +1114,14 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
}
}
-out_unlock:
mutex_unlock(&serial_mutex);
return ret;
+
+err:
+ uart->port.dev = NULL;
+ mutex_unlock(&serial_mutex);
+ return ret;
}
EXPORT_SYMBOL(serial8250_register_8250_port);
