Date: Tue, 5 Feb 2008 04:00:11 GMT From: KUROSAWA Takahiro <fwkg7679@mb.infoweb.ne.jp> To: freebsd-net@FreeBSD.org Subject: Re: kern/116837: [tun] [panic] [patch] ifconfig tunX destroy: panic Message-ID: <200802050400.m1540Bxi002324@freefall.freebsd.org>
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The following reply was made to PR kern/116837; it has been noted by GNATS.
From: KUROSAWA Takahiro <fwkg7679@mb.infoweb.ne.jp>
To: bug-followup@FreeBSD.org, bvanzant@ironport.com, jkpyvxmzsa@mailinator.com
Cc:
Subject: Re: kern/116837: [tun] [panic] [patch] ifconfig tunX destroy: panic
Date: Tue, 5 Feb 2008 12:58:31 +0900
It seems that lackness of waking up a process sleeping on select(2)
caused the panic. The following patch (instead of the previous one)
might fix the problem.
--- sys/net/if_tun.c 2008/01/11 04:14:11 1.1
+++ sys/net/if_tun.c 2008/01/29 02:22:43
@@ -249,15 +249,16 @@ tun_destroy(struct tun_softc *tp)
{
struct cdev *dev;
- /* Unlocked read. */
- KASSERT((tp->tun_flags & TUN_OPEN) == 0,
- ("tununits is out of sync - unit %d", TUN2IFP(tp)->if_dunit));
-
dev = tp->tun_dev;
+ /* destroy_dev() ensures no threads access /dev/tunX anymore. */
+ destroy_dev(dev);
bpfdetach(TUN2IFP(tp));
if_detach(TUN2IFP(tp));
if_free(TUN2IFP(tp));
- destroy_dev(dev);
+
+ funsetown(&tp->tun_sigio);
+ selwakeuppri(&tp->tun_rsel, PZERO + 1);
+ KNOTE_UNLOCKED(&tp->tun_rsel.si_note, 0);
knlist_destroy(&tp->tun_rsel.si_note);
mtx_destroy(&tp->tun_mtx);
free(tp, M_TUN);
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