svn commit: r186483 - head/sys/net
Kip Macy
kmacy at FreeBSD.org
Thu Dec 25 02:14:25 UTC 2008
Author: kmacy
Date: Thu Dec 25 02:14:25 2008
New Revision: 186483
URL: http://svn.freebsd.org/changeset/base/186483
Log:
- Close a race during which the open flag could be cleared but the tun_softc would still be referenced
by adding a separate TUN_CLOSED flag that is set after tunclose is done referencing it.
- drop the tun_mtx after the flag check to avoid holding it across if_detach which can recurse in to
if_tun.c
Modified:
head/sys/net/if_tun.c
Modified: head/sys/net/if_tun.c
==============================================================================
--- head/sys/net/if_tun.c Thu Dec 25 01:59:44 2008 (r186482)
+++ head/sys/net/if_tun.c Thu Dec 25 02:14:25 2008 (r186483)
@@ -79,6 +79,7 @@ struct tun_softc {
#define TUN_RWAIT 0x0040
#define TUN_ASYNC 0x0080
#define TUN_IFHEAD 0x0100
+#define TUN_CLOSED 0x0200
#define TUN_READY (TUN_OPEN | TUN_INITED)
@@ -256,9 +257,11 @@ tun_destroy(struct tun_softc *tp)
/* Unlocked read. */
mtx_lock(&tp->tun_mtx);
- if ((tp->tun_flags & TUN_OPEN) != 0)
+ if ((tp->tun_flags & (TUN_OPEN|TUN_CLOSED)) != TUN_CLOSED)
cv_wait_unlock(&tp->tun_cv, &tp->tun_mtx);
-
+ else
+ mtx_unlock(&tp->tun_mtx);
+
CURVNET_SET(TUN2IFP(tp)->if_vnet);
dev = tp->tun_dev;
bpfdetach(TUN2IFP(tp));
@@ -497,6 +500,7 @@ tunclose(struct cdev *dev, int foo, int
KNOTE_UNLOCKED(&tp->tun_rsel.si_note, 0);
TUNDEBUG (ifp, "closed\n");
+ tp->tun_flags |= TUN_CLOSED;
cv_broadcast(&tp->tun_cv);
mtx_unlock(&tp->tun_mtx);
return (0);
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