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[1/2] tty: serial_core: Fix serial console crash on port shutdown

Message ID 20161028120748.27763-2-robh@kernel.org
State New
Headers show

Commit Message

Rob Herring Oct. 28, 2016, 12:07 p.m. UTC 
From: Geert Uytterhoeven <geert+renesas@glider.be>


The port->console flag is always false, as uart_console() is called
before the serial console has been registered.

Hence for a serial port used as the console, uart_tty_port_shutdown()
will still be called when userspace closes the port, powering it down.
This may lead to a system lock up when the serial console driver writes
to the serial port's registers.

To fix this, move the setting of port->console after the call to
uart_configure_port(), which registers the serial console.

Fixes: 761ed4a94582ab29 ("tty: serial_core: convert uart_close to use tty_port_close")
Reported-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Acked-by: Rob Herring <robh@kernel.org>

Tested-by: Mugunthan V N <mugunthanvnm@ti.com>

Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

[robh: rebased on tty-linus]
Signed-off-by: Rob Herring <robh@kernel.org>

---
 drivers/tty/serial/serial_core.c | 2 ++
 1 file changed, 2 insertions(+)

-- 
2.10.1
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Patch

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 664c99aeeca5..ce8899c13af3 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2759,6 +2759,8 @@  int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
 
 	uart_configure_port(drv, state, uport);
 
+	port->console = uart_console(uport);
+
 	num_groups = 2;
 	if (uport->attr_group)
 		num_groups++;