svn commit: r229097 - stable/9/sys/dev/usb

[Hans Petter Selasky]

Author: hselasky
Date: Sat Dec 31 14:24:22 2011
New Revision: 229097
URL: http://svn.freebsd.org/changeset/base/229097

Log:
  MFC r228758:
  Fix for race against user-space applications trying to change the
  configuration on USB HUBs.
  
  PR:		kern/163091

Modified:
  stable/9/sys/dev/usb/usb_hub.c
Directory Properties:
  stable/9/sys/   (props changed)
  stable/9/sys/amd64/include/xen/   (props changed)
  stable/9/sys/boot/   (props changed)
  stable/9/sys/boot/i386/efi/   (props changed)
  stable/9/sys/boot/ia64/efi/   (props changed)
  stable/9/sys/boot/ia64/ski/   (props changed)
  stable/9/sys/boot/powerpc/boot1.chrp/   (props changed)
  stable/9/sys/boot/powerpc/ofw/   (props changed)
  stable/9/sys/cddl/contrib/opensolaris/   (props changed)
  stable/9/sys/conf/   (props changed)
  stable/9/sys/contrib/dev/acpica/   (props changed)
  stable/9/sys/contrib/octeon-sdk/   (props changed)
  stable/9/sys/contrib/pf/   (props changed)
  stable/9/sys/contrib/x86emu/   (props changed)

Modified: stable/9/sys/dev/usb/usb_hub.c
==============================================================================
--- stable/9/sys/dev/usb/usb_hub.c	Sat Dec 31 14:22:02 2011	(r229096)
+++ stable/9/sys/dev/usb/usb_hub.c	Sat Dec 31 14:24:22 2011	(r229097)
@@ -707,6 +707,13 @@ uhub_explore(struct usb_device *udev)
 		DPRINTF("Device is suspended!\n");
 		return (0);
 	}
+
+	/*
+	 * Make sure we don't race against user-space applications
+	 * like LibUSB:
+	 */
+	usbd_enum_lock(udev);
+
 	for (x = 0; x != hub->nports; x++) {
 		up = hub->ports + x;
 		portno = x + 1;
@@ -784,6 +791,8 @@ uhub_explore(struct usb_device *udev)
 		up->restartcnt = 0;
 	}
 
+	usbd_enum_unlock(udev);
+
 	/* initial status checked */
 	sc->sc_flags |= UHUB_FLAG_DID_EXPLORE;