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>
next in thread | raw e-mail | index | archive | help
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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200706232000.l5NK0EHZ095650>