Date: Wed, 27 Jul 2005 12:10:43 -0700 From: Brooks Davis <brooks@one-eyed-alien.net> To: Brooks Davis <brooks@one-eyed-alien.net> Cc: Wilko Bulte <wb@freebie.xs4all.nl>, freebsd-current@FreeBSD.org, Jung-uk Kim <jkim@FreeBSD.org>, Mike Jakubik <mikej@rogers.com> Subject: Re: dhclient taking all cpu Message-ID: <20050727191043.GA17885@odin.ac.hmc.edu> In-Reply-To: <20050726233933.GA13679@odin.ac.hmc.edu> References: <42E58007.9030202@rogers.com> <20050726193324.GA4603@odin.ac.hmc.edu> <20050726200059.GA47478@freebie.xs4all.nl> <200507261853.19211.jkim@FreeBSD.org> <20050726233933.GA13679@odin.ac.hmc.edu>
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On Tue, Jul 26, 2005 at 04:39:33PM -0700, Brooks Davis wrote:
> On Tue, Jul 26, 2005 at 06:53:17PM -0400, Jung-uk Kim wrote:
> > On Tuesday 26 July 2005 04:00 pm, Wilko Bulte wrote:
> > > On Tue, Jul 26, 2005 at 12:33:24PM -0700, Brooks Davis wrote..
> > >
> > > > On Mon, Jul 25, 2005 at 10:39:09PM -0400, Mike Jakubik wrote:
> > > > > On Mon, July 25, 2005 9:54 pm, Brooks Davis said:
> > > > > >>> Probably something wrong with your interface, but you
> > > > > >>> havent't provided any useful information so who knows. At
> > > > > >>> the very least, I need to know what interface you are
> > > > > >>> running on, something about it's status, and if both
> > > > > >>> dhclient processes are running.
> > > > > >>
> > > > > >> The interface is xl0 (3Com 3c905C-TX Fast Etherlink XL), and
> > > > > >> it worked in this machine fine for as long as i remember.
> > > > > >> This seems to have happened since a recent cvsup and
> > > > > >> buildworld from ~6-BETA to 7-CURRENT. I rebooted three
> > > > > >> times, and the problem occured rougly a minute after bootup.
> > > > > >> On the fourth time however, it seems to be ok so far.
> > > > > >
> > > > > > That sounds like a problem with the code that handles the
> > > > > > link state notifications in the interface driver. The
> > > > > > notifications are a reletivly new feature that we're only now
> > > > > > starting to use heavily so there are going to be bumps in the
> > > > > > road. It would be intresting to know if you see link state
> > > > > > messages promptly if you plug and unplug the network cable.
> > > > >
> > > > > It seems to be back at it again, this time it took longer to
> > > > > kick in. Here is a "ps auxw|grep dhclient" :
> > > > >
> > > > > _dhcp 219 93.5 0.2 1484 1136 ?? Rs 8:49PM =20
> > > > > 5:06.00 dhclient: xl0 (dhclient)
> > > > > root 193 0.0 0.2 1484 1088 d0- S 8:49PM =20
> > > > > 0:00.02 dhclient: xl0 [priv] (dhclient)
> > > > >
> > > > > top:
> > > > >
> > > > > PID USERNAME THR PRI NICE SIZE RES STATE TIME =20
> > > > > WCPU COMMAND 219 _dhcp 1 129 0 1484K 1136K RUN =20
> > > > > 9:33 94.24% dhclient
> > > > >
> > > > > Nothing in dmesg about link state changes on xl0. Unplugging
> > > > > and replugging the network cable results in link state
> > > > > notification within a couple seconds.
> > > >
> > > > Could you see what happens if you run dhclient in the foreground?
> > > > Just running "dhclient -d xl0" should do it. I'd like to know
> > > > what sort of output it's generating.
> > >
> > > In my case it is not displaying anything:
> > >
> > >
> > > chuck#dhclient -d ath0
> > > DHCPREQUEST on ath0 to 255.255.255.255 port 67
> > > DHCPACK from 192.168.5.254
> > > bound to 192.168.5.20 -- renewal in 21600 seconds.
> > >
> > > <nothing>
> > >
> > > I can tell the phenomenon occurs when my laptop fan springs to
> > > life:
> > >
> > > CPU states: 96.5% user, 0.0% nice, 2.7% system, 0.8% interrupt,=20
> > > 0.0% idle
> > > Mem: 48M Active, 28M Inact, 50M Wired, 680K Cache, 34M Buf, 115M
> > > Free Swap: 257M Total, 257M Free
> > >
> > > PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU
> > > COMMAND 719 _dhcp 1 129 0 1384K 1092K RUN 2:14
> > > 93.55% dhclient 607 root 1 98 0 34584K 21212K select =20
> > > 0:09 1.81% Xorg 663 wb 4 20 0 46712K 40224K kserel =20
> > > 0:27 0.00% mozilla-bin 503 root 1 8 0 1184K 796K
> > > nanslp 0:07 0.00% powerd
> > >
> > > Took (best guess) approx 5-10 minutes for the effect to kick in.
> >=20
> > FYI, I have the same issues with bge(4) and ndis(4).
>=20
> I've seen it on ath and em interfaces now, but am not sure what's going
> on. and have no idea how to reproduce the problem. As also reported by
> Bakul Shah, we seem to be getting into a state where receive_packet() is
> spinning. I'm not seeing an obvious way for this to be possible.
I think I've found it. There was a really odd typo (=3D instead of +) in
the code that handles undersized captures on the bpf socket. Please try
the following patch and see if it solves the problem. I'm testing here,
but I don't have a reliable way to trigger the bug. The fix is fairly
obvious so I'll commit it to head shortly.
-- Brooks
=3D=3D=3D=3D //depot/user/brooks/cleanup/sbin/dhclient/bpf.c#3 - /usr/home/=
brooks/working/freebsd/p4/cleanup/sbin/dhclient/bpf.c =3D=3D=3D=3D
@@ -316,19 +316,19 @@
continue;
}
=20
+ /* Skip over the BPF header... */
+ interface->rbuf_offset +=3D hdr.bh_hdrlen;
+
/*
* If the captured data wasn't the whole packet, or if
* the packet won't fit in the input buffer, all we can
* do is drop it.
*/
if (hdr.bh_caplen !=3D hdr.bh_datalen) {
- interface->rbuf_offset +=3D hdr.bh_hdrlen =3D hdr.bh_caplen;
+ interface->rbuf_offset +=3D hdr.bh_caplen;
continue;
}
=20
- /* Skip over the BPF header... */
- interface->rbuf_offset +=3D hdr.bh_hdrlen;
-
/* Decode the physical header... */
offset =3D decode_hw_header(interface->rbuf,
interface->rbuf_offset, hfrom);
--=20
Any statement of the form "X is the one, true Y" is FALSE.
PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4
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