Re: [patch] usb-skeleton leaking locks on open.
From: Mark Gross
Date: Mon Sep 24 2007 - 12:36:59 EST
forgot to CC greg ...
On Mon, Sep 24, 2007 at 09:18:22AM -0700, Mark Gross wrote:
> 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 <mgross@xxxxxxxxxxxxxxx>
> diff -urN -X linux-2.6.23-rc7/Documentation/dontdiff linux-2.6.23-rc7/drivers/usb/usb-skeleton.c linux-2.6.23-rc7-bugfix/drivers/usb/usb-skeleton.c
> --- linux-2.6.23-rc7/drivers/usb/usb-skeleton.c 2007-09-24 08:57:54.000000000 -0700
> +++ linux-2.6.23-rc7-bugfix/drivers/usb/usb-skeleton.c 2007-09-24 09:01:43.000000000 -0700
> @@ -125,6 +125,7 @@
> /* save our object in the file's private structure */
> file->private_data = dev;
> + mutex_unlock(&dev->io_mutex);
> return retval;
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