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| author | Alan Stern <stern@rowland.harvard.edu> | 2017-09-21 16:12:01 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-09-22 18:29:00 +0200 |
| commit | 6e76c01e71551cb221c1f3deacb9dcd9a7346784 (patch) | |
| tree | 7d82a827794b423e0e7232a87f0656f2aa5add8a /drivers | |
| parent | 786de92b3cb26012d3d0f00ee37adf14527f35c4 (diff) | |
| download | linux-6e76c01e71551cb221c1f3deacb9dcd9a7346784.tar.gz linux-6e76c01e71551cb221c1f3deacb9dcd9a7346784.tar.bz2 linux-6e76c01e71551cb221c1f3deacb9dcd9a7346784.zip | |
USB: gadgetfs: fix copy_to_user while holding spinlock
The gadgetfs driver as a long-outstanding FIXME, regarding a call of
copy_to_user() made while holding a spinlock. This patch fixes the
issue by dropping the spinlock and using the dev->udc_usage mechanism
introduced by another recent patch to guard against status changes
while the lock isn't held.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
CC: <stable@vger.kernel.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/gadget/legacy/inode.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index 684900fcfe24..956b3dc7c3a4 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -983,11 +983,14 @@ ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr) retval = -EIO; else { len = min (len, (size_t)dev->req->actual); -// FIXME don't call this with the spinlock held ... + ++dev->udc_usage; + spin_unlock_irq(&dev->lock); if (copy_to_user (buf, dev->req->buf, len)) retval = -EFAULT; else retval = len; + spin_lock_irq(&dev->lock); + --dev->udc_usage; clean_req (dev->gadget->ep0, dev->req); /* NOTE userspace can't yet choose to stall */ } |