Date: Wed, 14 Mar 2007 02:50:07 GMT From: Craig Leres <leres@ee.lbl.gov> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/109152: [rp] RocketPort panic from device_unbusy() Message-ID: <200703140250.l2E2o7vg050044@freefall.freebsd.org>
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The following reply was made to PR kern/109152; it has been noted by GNATS.
From: Craig Leres <leres@ee.lbl.gov>
To: bug-followup@FreeBSD.org
Cc: ambrisko@ambrisko.com
Subject: Re: kern/109152: [rp] RocketPort panic from device_unbusy()
Date: Tue, 13 Mar 2007 19:27:01 -0700
I was still able to crash Doug Ambrisko's version of the rp driver.
I think the problem is that in some cases rp_handle_port() calls
rpclose() which calls device_unbusy(). Later rpclose() is called
again and we hit the panic.
I looked at the last known good version of the driver I'd used,
1.45.2.2 from 4.10-RELEASE, and found it has code to avoid calling
rpclose() twice. I did something similar that seems to work.
Note: The appended diffs are against version 1.67.2.2 of rp.c.
Craig
===================================================================
RCS file: RCS/rp.c,v
retrieving revision 1.2
retrieving revision 1.3
diff -c -r1.2 -r1.3
*** rp.c 2007/03/08 04:07:10 1.2
--- rp.c 2007/03/14 02:23:17 1.3
***************
*** 573,578 ****
--- 573,579 ----
static void rpbreak(struct tty *, int);
static void rpclose(struct tty *tp);
+ static void rphardclose(struct tty *tp);
static int rpmodem(struct tty *, int, int);
static int rpparam(struct tty *, struct termios *);
static void rpstart(struct tty *);
***************
*** 697,703 ****
if((tp->t_state & TS_CARR_ON)) {
(void)ttyld_modem(tp, 0);
if(ttyld_modem(tp, 0) == 0) {
! rpclose(tp);
}
}
}
--- 698,704 ----
if((tp->t_state & TS_CARR_ON)) {
(void)ttyld_modem(tp, 0);
if(ttyld_modem(tp, 0) == 0) {
! rphardclose(tp);
}
}
}
***************
*** 936,941 ****
--- 937,952 ----
rpclose(struct tty *tp)
{
struct rp_port *rp;
+
+ rp = tp->t_sc;
+ rphardclose(tp);
+ device_unbusy(rp->rp_ctlp->dev);
+ }
+
+ static void
+ rphardclose(struct tty *tp)
+ {
+ struct rp_port *rp;
CHANNEL_t *cp;
rp = tp->t_sc;
***************
*** 959,965 ****
tp->t_actout = FALSE;
wakeup(&tp->t_actout);
wakeup(TSA_CARR_ON(tp));
- device_unbusy(rp->rp_ctlp->dev);
}
static void
--- 970,975 ----
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