Date: Thu, 4 Sep 2003 05:10:12 -0700 (PDT) From: "James F. Hranicky" <jfh@cise.ufl.edu> To: freebsd-bugs@FreeBSD.org Subject: Re: conf/56031: ipfw hangs on every invocation Message-ID: <200309041210.h84CACrV044328@freefall.freebsd.org>
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The following reply was made to PR conf/56031; it has been noted by GNATS.
From: "James F. Hranicky" <jfh@cise.ufl.edu>
To: Robert Watson <rwatson@FreeBSD.org>
Cc: FreeBSD-gnats-submit@FreeBSD.org, admin@cise.ufl.edu,
freebsd-bugs@FreeBSD.org
Subject: Re: conf/56031: ipfw hangs on every invocation
Date: Thu, 4 Sep 2003 08:01:42 -0400
On Wed, 3 Sep 2003 11:45:41 -0400 (EDT)
Robert Watson <rwatson@FreeBSD.org> wrote:
> On Wed, 3 Sep 2003, James F. Hranicky wrote:
> I'd step up to the ioctl in question, and then see if it really hangs in
> the ioctl(), or if it gets past and starts spinning. If it's the ioctl(),
> it would be very helpful to know which file descriptor it's on, and what
> the arguments are. If it's not the ioctl() call, we need to figure out
> which loop isn't taking something important into account.
I think I've found it. First off, I neglected to mention I've added
IPFW2=TRUE
to /etc/make.conf, so I'm using ipfw2 (sorry!).
After tracing through, it does seem to be a logic error in ipfw2.c .
At line 1036, there a loop like so:
for (l = rule->act_ofs, cmd = rule->cmd ;
l > 0 ; l -= F_LEN(cmd) , cmd += F_LEN(cmd)) {
The loop is supposed to quit when l == 0, and l is supposed to be decremented
by F_LEN(cmd) each time.
F_LEN is defined as
#define F_LEN_MASK 0x3f
#define F_LEN(cmd) ((cmd)->len & F_LEN_MASK)
Checking the values of the cmd struct:
(gdb) p *cmd
$6 = {opcode = O_NOP, len = 0 '\000', arg1 = 0}
Darn, l is always decremented by 0.
I'll probably fix the problem on my end by temporarily disabling ipfw2 (since I'm
not really even using it at the moment).
Hope this helps.
Jim
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