hso_spinlockfix.patch]

-------- Original Message --------
Subject: [PATCH] hso_spinlockfix.patch
Date: Wed, 14 Jan 2009 10:54:51 +0100
From: Denis Joseph Barrow <[email protected]>
To: Linux USB kernel mailing list <[email protected]>, Linux netdev Mailing list <[email protected]>

Hi,
This is a really important fix it fixes a consistent kernel deadlock when the hso driver starts going. It's against 2.6.29-rc1, 2.6.29-rc6 worked fine.

This patch obviously wasn't tested & I neither I or Filip was subscribed to the tty mailing list to catch it.

Even with this patch the driver is still broken.
opening the serial port on the driver a second time causes a -EIO, I've yet to figure out what but it is not returned from hso_serial_open but a parent function.

This patch fixes a double grabbing of a spinlock all
functions which call put_rxbuf_data already have serial->serial_lock grabbed.

Index: linux-2.6/drivers/net/usb/hso.c
===================================================================
@@ -2043,9 +2043,7 @@
 		return -2;
 	}
 
-	spin_lock(&serial->serial_lock);
 	tty = tty_kref_get(serial->tty);
-	spin_unlock(&serial->serial_lock);
 
 	/* Push data to tty */
 	if (tty) {

best regards,
D.J. Barrow

Linux Kernel Developer
Option NV, Gaston Geenslaan 14, 3001 Leuven, Belgium
 
T: +32 16 311 621
F: +32 16 207 164
[email protected]
www.option.com

Disclaimer:
http://www.option.com/company/disclaimer.shtml


-- 
best regards,
D.J. Barrow

Linux Kernel Developer
Option NV, Gaston Geenslaan 14, 3001 Leuven, Belgium
 
T: +32 16 311 621
F: +32 16 207 164
[email protected]
www.option.com

Disclaimer:
http://www.option.com/company/disclaimer.shtml

This patch fixes a double grabbing of a spinlock all
functions which call put_rxbuf_data already have serial->serial_lock grabbed.

Index: linux-2.6/drivers/net/usb/hso.c
===================================================================
@@ -2043,9 +2043,7 @@
 		return -2;
 	}
 
-	spin_lock(&serial->serial_lock);
 	tty = tty_kref_get(serial->tty);
-	spin_unlock(&serial->serial_lock);
 
 	/* Push data to tty */
 	if (tty) {