kern/174849: bxe driver can hang kernel when reset

[Mike Karels]

>Number:         174849
>Category:       kern
>Synopsis:       bxe driver can hang kernel when reset
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Dec 31 03:00:00 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Mike Karels
>Release:        FreeBSD 10.0-CURRENT amd64
>Organization:
McAfee, Inc
>Environment:
System: FreeBSD freebsd-current.karels.net 10.0-CURRENT FreeBSD 10.0-CURRENT #1 r244048: Sun Dec  9 18:48:31 UTC 2012     root at snap.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64
	
>Description:
	Resetting the bxe driver can hang the kernel.
	Note: problem was found and fixed on a FreeBSD 8.2 derivative;
	the patch compiles with -current.
>How-To-Repeat:
	ifconfig bxe0 down; ifconfig bxe0 up
>Fix:
--- if_bxe.c.orig	2012-12-22 19:56:36.000000000 -0600
+++ if_bxe.c	2012-12-22 20:17:12.000000000 -0600
@@ -9610,8 +9610,10 @@
 			    __FUNCTION__, fp->index);
 
 			BXE_FP_LOCK(fp);
-			while ((m = buf_ring_dequeue_sc(fp->br)) != NULL)
+			while ((m = buf_ring_dequeue_sc(fp->br)) != NULL) {
 				m_freem(m);
+				fp->br = NULL;
+			}
 			BXE_FP_UNLOCK(fp);
 		}
 	}
>Release-Note:
>Audit-Trail:
>Unformatted: