Date: Sat, 23 Jun 2007 20:00:14 GMT From: Kazuaki ODA <kazuaki@aliceblue.jp> To: freebsd-usb@FreeBSD.org Subject: Re: usb/113964: [patch] ucom(4): kernel panic when dropping a connection Message-ID: <200706232000.l5NK0EHZ095650@freefall.freebsd.org>
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The following reply was made to PR usb/113964; it has been noted by GNATS. From: Kazuaki ODA <kazuaki@aliceblue.jp> To: "M. Warner Losh" <imp@bsdimp.com> Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: Re: usb/113964: [patch] ucom(4): kernel panic when dropping a connection Date: Sun, 24 Jun 2007 04:56:22 +0900 M. Warner Losh wrote: > In message: <200706231136.l5NBa61H001748@eyes.aliceblue.jp> > Kazuaki ODA <kazuaki@aliceblue.jp> writes: > : I don't know the proper fix but the following patch is workaround for > : me. > : > : --- ucom.c.patch begins here --- > : --- sys/dev/usb/ucom.c.orig 2007-06-22 23:45:37.000000000 +0900 > : +++ sys/dev/usb/ucom.c 2007-06-23 17:47:18.000000000 +0900 > : @@ -532,6 +532,9 @@ > : if (sc->sc_dying) > : return; > : > : + if (sc->sc_oxfer == NULL) > : + return; > : + > : s = spltty(); > : > : if (tp->t_state & TS_TBLOCK) { > : --- ucom.c.patch ends here --- > > This is a good workaround. However, why does the tty->t_oproc get > called after the tty->t_close routine which sets sc->sc_oxfer to NULL? > > Warner Unfortunately, I have no idea. But it seems the changes of tty subsystem and ucom.c rev. 1.56 are related to the issue. * On 5.x-RELEASE, where ucom.c rev. 1.56 has been MFCed, we get no panic. * On 6.x-RELEASE or 7.0-CURRENT, we get a panic. * After backing out ucom.c rev. 1.56, no panic on 6.x-RELEASE or 7.0-CURRENT. -- Kazuaki ODA
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