Date: Wed, 14 Feb 2001 21:11:44 +0100 From: "Peter Blok" <Peter.Blok@inter.NL.net> To: "'Andrew Gallatin'" <gallatin@cs.duke.edu>, <Peter.Blok@inter.NL.net> Cc: <freebsd-alpha@FreeBSD.ORG> Subject: RE: unaligned access Message-ID: <000101c096c2$5a901df0$8a02a8c0@ntpc> In-Reply-To: <14986.54140.54832.224655@grasshopper.cs.duke.edu>
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Drew, mpd-netgraph is the multi-link ppp netgraph daemon. It uses the kernel netgraph functionality, to connect communication end-points in the kernel. I am using it to setup a pptp connection to my internet provider. All the handshaking stuff is done at user space, the comms are done in the kernel. With pppd I was only able to do 55KB/s, with netgraph it is running at 100KB/s which is the providers limit. The user level part breaks. I haven't reached the kernel part yet. Thanks for the tips, Peter -----Original Message----- From: Andrew Gallatin [mailto:gallatin@cs.duke.edu] Sent: Wednesday, February 14, 2001 19:51 To: Peter.Blok@inter.NL.net Cc: freebsd-alpha@FreeBSD.ORG Subject: Re: unaligned access Peter.Blok@inter.NL.net writes: > Hi, > > I am trying to port mpd-netgraph to alpha, but i'm getting a lot of uac's. I am trying to use gdb, but I am not used to gdb. When I try to lookup the address it tells me it is outside the map. > > Is it possible to make it core dump instead of this warning? It would be nice if you can say: run this command and core dump on uac. > > Are tools available to determine in which function the uac takes place? I can make something myself with perl and nm, but if there is already something out there? > > Which compiler options bring this up at compile time? > > Peter I don't know what mpd netgraph is. Can you elaborate further? Is the kernel crashing, or is it a userland app? If it is a userland app, try running uap -s prior to invoking gdb. Then run gdb on the app. You should get a SIGBUS at the PC of the unaligned access. If gdb misbehaves, try increasing the size of the heuristic-fence-post. Eg: (gdb) set heuristic-fence-post 0xffffffffffffffff Hope this helps, Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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