svn commit: r346602 - head/sys/net

Kyle Evans kevans at FreeBSD.org
Tue Sep 3 14:07:44 UTC 2019


Author: kevans
Date: Tue Apr 23 17:28:28 2019
New Revision: 346602
URL: https://svnweb.freebsd.org/changeset/base/346602

Log:
  tun(4): Defer clearing TUN_OPEN until much later
  
  tun destruction will not continue until TUN_OPEN is cleared. There are brief
  moments in tunclose where the mutex is dropped and we've already cleared
  TUN_OPEN, so tun_destroy would be able to proceed while we're in the middle
  of cleaning up the tun still. tun_destroy should be blocked until these
  parts (address/route purges, mostly) are complete.
  
  PR:		233955
  MFC after:	2 weeks

Modified:
  head/sys/net/if_tun.c

Modified: head/sys/net/if_tun.c
==============================================================================
--- head/sys/net/if_tun.c	Tue Apr 23 17:18:20 2019	(r346601)
+++ head/sys/net/if_tun.c	Tue Apr 23 17:28:28 2019	(r346602)
@@ -500,8 +500,6 @@ tunclose(struct cdev *dev, int foo, int bar, struct th
 	ifp = TUN2IFP(tp);
 
 	mtx_lock(&tp->tun_mtx);
-	tp->tun_flags &= ~TUN_OPEN;
-	tp->tun_pid = 0;
 
 	/*
 	 * junk all pending output
@@ -540,6 +538,8 @@ tunclose(struct cdev *dev, int foo, int bar, struct th
 	selwakeuppri(&tp->tun_rsel, PZERO + 1);
 	KNOTE_LOCKED(&tp->tun_rsel.si_note, 0);
 	TUNDEBUG (ifp, "closed\n");
+	tp->tun_flags &= ~TUN_OPEN;
+	tp->tun_pid = 0;
 
 	cv_broadcast(&tp->tun_cv);
 	mtx_unlock(&tp->tun_mtx);




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