From 5b89db02a5a7c8bad3c6fb7888778082a441b385 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Tue, 16 Jan 2007 22:56:26 -0800 Subject: [PATCH] USB: gadgetfs race fix This resolves a race in gadgetfs associated with changing device/ep0 when processing control requests. The fix is to change that state earlier, when the control response is issued, so there's no window in which userspace could see the wrong state; and enlarge the scope of the spinlock during the ep0 request completion handler. Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/inode.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c index ea8e3160d05..e5ce4f0bb7c 100644 --- a/drivers/usb/gadget/inode.c +++ b/drivers/usb/gadget/inode.c @@ -933,28 +933,24 @@ static void clean_req (struct usb_ep *ep, struct usb_request *req) static void ep0_complete (struct usb_ep *ep, struct usb_request *req) { struct dev_data *dev = ep->driver_data; + unsigned long flags; int free = 1; /* for control OUT, data must still get to userspace */ + spin_lock_irqsave(&dev->lock, flags); if (!dev->setup_in) { dev->setup_out_error = (req->status != 0); if (!dev->setup_out_error) free = 0; dev->setup_out_ready = 1; ep0_readable (dev); - } else { - unsigned long flags; - - spin_lock_irqsave(&dev->lock, flags); - if (dev->state == STATE_DEV_SETUP) - dev->state = STATE_DEV_CONNECTED; - spin_unlock_irqrestore(&dev->lock, flags); } /* clean up as appropriate */ if (free && req->buf != &dev->rbuf) clean_req (ep, req); req->complete = epio_complete; + spin_unlock_irqrestore(&dev->lock, flags); } static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len) @@ -1036,6 +1032,13 @@ ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr) spin_lock_irq (&dev->lock); if (retval) goto done; + + if (dev->state != STATE_DEV_SETUP) { + retval = -ECANCELED; + goto done; + } + dev->state = STATE_DEV_CONNECTED; + if (dev->setup_out_error) retval = -EIO; else { @@ -1187,6 +1190,7 @@ ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr) if (dev->setup_in) { retval = setup_req (dev->gadget->ep0, dev->req, len); if (retval == 0) { + dev->state = STATE_DEV_CONNECTED; spin_unlock_irq (&dev->lock); if (copy_from_user (dev->req->buf, buf, len)) retval = -EFAULT; -- 2.20.1