goldfish: locking bugs in goldfish_pipe_read_write()

We recently messed up the error handling here.  We can return with the
pipe->lock held or sometimes we unlock twice by mistake.

Fixes: 2f3be88237 ('goldfish_pipe: Pin pages to memory while copying and other cleanups')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dan Carpenter 2016-02-02 12:48:09 +03:00 committed by Greg Kroah-Hartman
parent d40a094644
commit 5fae054c2b

View File

@ -313,7 +313,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
!is_write, 0, &page, NULL);
up_read(&current->mm->mmap_sem);
if (ret < 0)
return ret;
break;
if (dev->version) {
/* Device version 1 or newer (qemu-android) expects the
@ -400,22 +400,16 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
while (test_bit(wakeBit, &pipe->flags)) {
if (wait_event_interruptible(
pipe->wake_queue,
!test_bit(wakeBit, &pipe->flags))) {
ret = -ERESTARTSYS;
break;
}
!test_bit(wakeBit, &pipe->flags)))
return -ERESTARTSYS;
if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)) {
ret = -EIO;
break;
}
if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
return -EIO;
}
/* Try to re-acquire the lock */
if (mutex_lock_interruptible(&pipe->lock)) {
ret = -ERESTARTSYS;
break;
}
if (mutex_lock_interruptible(&pipe->lock))
return -ERESTARTSYS;
}
mutex_unlock(&pipe->lock);