[PATCH 105/142] USB: usb-skeleton leaking locks on open

Greg Kroah-Hartman <[email protected]>
Newsgroups gmane.linux.usb.devel
Message-ID <[email protected]>
From: Mark Gross <[email protected]>

This weekend I was hacking around with a trivial USB driver for talking
to the boot load firmware of a USB Bit Whacker.  It's running the
MicroChip Pic18 boot loader firmware and I'm putting together a flash
program for writing new FW to the thing.

Anyway in my use of the usb-skeleton.c as my starting point I discovered
my test program was getting hung up after attempting to write a buffer.
The application and driver where hung in a way that required me to
reboot to get it to clean up so I could try again.

It turned out the code path through skel_open can grap the driver's
io_mutex lock and forget to release it.

The following patch fixes the problem for me.

Signed-off-by: Mark Gross <[email protected]>
Cc: Oliver Neukum <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/usb/usb-skeleton.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 8de11de..c815a40 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -125,6 +125,7 @@ static int skel_open(struct inode *inode, struct file *file)
 
 	/* save our object in the file's private structure */
 	file->private_data = dev;
+	mutex_unlock(&dev->io_mutex);
 
 exit:
 	return retval;
-- 
1.5.3.4


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