From c7d8c1c6e0a25cd5ee6b6a4e4e28a1c7c12d3ce6 Mon Sep 17 00:00:00 2001 From: Hans Petter Selasky Date: Fri, 17 Jan 2014 08:21:09 +0000 Subject: [PATCH] Close a minor deadlock. MFC after: 1 week --- sys/dev/usb/usb_dev.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/sys/dev/usb/usb_dev.c b/sys/dev/usb/usb_dev.c index 9e3cef5220a..c5ee368fc9b 100644 --- a/sys/dev/usb/usb_dev.c +++ b/sys/dev/usb/usb_dev.c @@ -597,6 +597,13 @@ usb_fifo_free(struct usb_fifo *f) mtx_unlock(f->priv_mtx); mtx_lock(&usb_ref_lock); + /* + * Check if the "f->refcount" variable reached zero + * during the unlocked time before entering wait: + */ + if (f->refcount == 0) + break; + /* wait for sync */ cv_wait(&f->cv_drain, &usb_ref_lock); }