Date: Fri, 26 Feb 1999 03:30:17 -0500 (EST) From: sab@yin.vegamuse.org To: FreeBSD-gnats-submit@freebsd.org Subject: i386/10273: Kernel crash with multiport serial enabled and misconfigured master port Message-ID: <199902260830.DAA17158@yang.vegamuse.org>
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>Number: 10273
>Category: i386
>Synopsis: Kernel crash with multiport serial enabled and misconfigured master port
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Feb 26 10:10:03 PST 1999
>Closed-Date:
>Last-Modified:
>Originator: Stephen Kiernan
>Release: FreeBSD 4.0-CURRENT i386
>Organization:
>Environment:
BOCA 6-port multiport serial card
>Description:
When multiport serial card is enabled in the kernel
(options COM_MULTIPORT) and the master port is setup incorrectly
(read: not configured), the kernel will panic on boot when it
tries setting up one of the multiport card serial ports.
There is a section of the sioattach code in i386/isa/sio.c which
assumes that find_isadev will return a non-NULL pointer to a
struct isa_device. What will happen if the master port is not
configured is find_isadev will return NULL and then the aforementioned
section of code will access the id_irq structure member. This causes
the kernel to panic due to a NULL pointer reference.
>How-To-Repeat:
Enabled multiport serial with multiport card installed.
options COM_MULTIPORT
Do not configure the master port with an irq
Build the kernel and reboot.
Watch the kernel try to set up the first multiport serial port and
panic.
>Fix:
--- sio.c.orig Fri Feb 26 02:48:27 1999
+++ sio.c Fri Feb 26 02:58:09 1999
@@ -1027,13 +1027,15 @@
#ifdef COM_MULTIPORT
if (COM_ISMULTIPORT(isdp)) {
+ struct isa_device *idev;
com->multiport = TRUE;
printf(" (multiport");
if (unit == COM_MPMASTER(isdp))
printf(" master");
printf(")");
- com->no_irq = find_isadev(isa_devtab_tty, &siodriver,
- COM_MPMASTER(isdp))->id_irq == 0;
+ idev = find_isadev(isa_devtab_tty, &siodriver,
+ COM_MPMASTER(isdp));
+ com->no_irq = (idev == NULL) || (idev->id_irq == 0);
}
#endif /* COM_MULTIPORT */
if (unit == comconsole)
>Release-Note:
>Audit-Trail:
>Unformatted:
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