svn commit: r237398 - head/sys/cam

[Alexander Motin]

Author: mav
Date: Thu Jun 21 14:35:46 2012
New Revision: 237398
URL: http://svn.freebsd.org/changeset/base/237398

Log:
  In camisr() clear CAM_SIM_ON_DONEQ flag after camisr_runqueue() purged SIM
  done queue. Clearing it before caused extra SIM queueing in some cases.
  It was invisible during normal operation, but during USB device unplug and
  respective SIM destruction it could keep pointer on SIM without having
  counted reference and as result crash the system by use afer free.
  
  Reported by:	hselasky
  MFC after:	1 week

Modified:
  head/sys/cam/cam_xpt.c

Modified: head/sys/cam/cam_xpt.c
==============================================================================
--- head/sys/cam/cam_xpt.c	Thu Jun 21 13:53:28 2012	(r237397)
+++ head/sys/cam/cam_xpt.c	Thu Jun 21 14:35:46 2012	(r237398)
@@ -5005,8 +5005,8 @@ camisr(void *dummy)
 		while ((sim = TAILQ_FIRST(&queue)) != NULL) {
 			TAILQ_REMOVE(&queue, sim, links);
 			CAM_SIM_LOCK(sim);
-			sim->flags &= ~CAM_SIM_ON_DONEQ;
 			camisr_runqueue(&sim->sim_doneq);
+			sim->flags &= ~CAM_SIM_ON_DONEQ;
 			CAM_SIM_UNLOCK(sim);
 		}
 		mtx_lock(&cam_simq_lock);