Bug #82

Problems with pppd

Added by eric.j.christeson about 8 years ago. Updated over 7 years ago.

Status:ClosedStart date:
Priority:NormalDue date:
Assignee:-% Done:

0%

Category:-
Target version:-

Description

I spent this past week updating my Dragonfly 1.2 box to 1.4 source
downloaded on Jan. 20, 2006. I am using dialup with pppd. The
upgrade went w/out problem except that I can't access the Internet.
The ppp chat script seems to connect fine, but trying a ping causes
ping to hang. It is only the ping process, the rest of the box is
quite usable. The ping process will not respond to ^C or kill -9. If
I attach gdb, gdb hangs also, but is killable. I have the kernel
compiled with DDB, but I haven't figured out how to get anything
interesting out of it yet.
Attached are the boot dmesg and kernel config.

Thanks,
Eric

dmesg.out (5.28 KB) eric.j.christeson, 01/27/2006 07:07 PM

robin (5.44 KB) eric.j.christeson, 01/27/2006 07:07 PM

ppp_tty.c.diff Magnifier (605 Bytes) qhwt+dfly, 01/28/2006 05:25 AM

ppp.patch Magnifier (1.43 KB) qhwt+dfly, 02/04/2006 04:39 AM

History

#1 Updated by qhwt+dfly about 8 years ago

On Fri, Jan 27, 2006 at 01:00:05PM -0600, Eric J. Christeson wrote:
> I spent this past week updating my Dragonfly 1.2 box to 1.4 source
> downloaded on Jan. 20, 2006. I am using dialup with pppd. The
> upgrade went w/out problem except that I can't access the Internet.
> The ppp chat script seems to connect fine, but trying a ping causes
> ping to hang. It is only the ping process, the rest of the box is
> quite usable. The ping process will not respond to ^C or kill -9. If
> I attach gdb, gdb hangs also, but is killable. I have the kernel
> compiled with DDB, but I haven't figured out how to get anything
> interesting out of it yet.

Can you try the attached patch and re-compile the kernel?
Thanks.

#2 Updated by corecode about 8 years ago

fix committed by yonetani

#3 Updated by eric.j.christeson about 8 years ago

On 2/2/06, YONETANI Tomokazu <> wrote:
> On Tue, Jan 31, 2006 at 09:24:59PM -0600, ejc wrote:
> > I got a dump thanks to your excellent instructions. It didn't tell me
> > much, but I saved it and uploaded kernel.0.gz and vmcore.0.gz to
> > http://www.crackpot.org/~ejc/dragonfly/
>
> Though my laptop has an RJ-11 port, I have no idea how I can make this
> on-chip modem work. I need to find a real modem before I can dig in
> further. In the meantime I looked at your kernel dump, and I think
> (IIUC) ppp driver has a serializer problem. Can you try a kernel with
> the following options enabled(seems it's commented out now):
> options INVARIANTS
> options INVARIANT_SUPPORT
>
> and run the following command(as root) before running pppd and ping:
> sysctl debug.trace_on_panic=1 debug.debugger_on_panic=1
> if my guess is right, you'll see a panic in lwkt_serialize_enter()
> (but it may be far before you run the ping command...).

I did this last night and have uploaded the files to
http://www.crackpot.org/~ejc/dragonfly/

Out of curiosity, how does one view the coredump file and get stack
traces from it?
Thanks for your time and patience.

Eric

#4 Updated by wa1ter about 8 years ago

ejc wrote:
[...]
> Out of curiosity, how does one view the coredump file and get stack
> traces from it?

These are reasonable places to start:
http://wiki.dragonflybsd.org/index.php/Create_a_coredump
http://wiki.dragonflybsd.org/index.php/Kernel_Debugging_in_DragonFly_BSD

One little thing that might not be obvious to a newcomer: any time you
build a new kernel, the 'old' kernel is stripped of debugging symbols
and saved as kernel.old.

If you need to reboot kernel.old (e.g. the new kernel panics on boot)
then be careful to point gdb to the 'new' kernel which still has the
debugging symbols.

#5 Updated by corecode about 8 years ago

walt wrote:
> ejc wrote:
> [...]
>
>>Out of curiosity, how does one view the coredump file and get stack
>>traces from it?
>
>
> These are reasonable places to start:
> http://wiki.dragonflybsd.org/index.php/Create_a_coredump
> http://wiki.dragonflybsd.org/index.php/Kernel_Debugging_in_DragonFly_BSD
>
> One little thing that might not be obvious to a newcomer: any time you
> build a new kernel, the 'old' kernel is stripped of debugging symbols
> and saved as kernel.old.
>
> If you need to reboot kernel.old (e.g. the new kernel panics on boot)
> then be careful to point gdb to the 'new' kernel which still has the
> debugging symbols.

yea. savecore might even not work if called from the .old kernel. then
you will have to point savecore manually to the panic'ed kernel.

cheers
simon

#6 Updated by qhwt+dfly about 8 years ago

On Fri, Feb 03, 2006 at 12:23:49PM -0600, ejc wrote:
> > Though my laptop has an RJ-11 port, I have no idea how I can make this
> > on-chip modem work. I need to find a real modem before I can dig in
> > further. In the meantime I looked at your kernel dump, and I think
> > (IIUC) ppp driver has a serializer problem. Can you try a kernel with
> > the following options enabled(seems it's commented out now):
> > options INVARIANTS
> > options INVARIANT_SUPPORT
> >
> > and run the following command(as root) before running pppd and ping:
> > sysctl debug.trace_on_panic=1 debug.debugger_on_panic=1
> > if my guess is right, you'll see a panic in lwkt_serialize_enter()
> > (but it may be far before you run the ping command...).
>
> I did this last night and have uploaded the files to
> http://www.crackpot.org/~ejc/dragonfly/

Ok, please try the attached patch, with above options enabled
(and leave the last patch applied).

#7 Updated by eric.j.christeson about 8 years ago

On 2/4/06, YONETANI Tomokazu <> wrote:
> On Fri, Feb 03, 2006 at 12:23:49PM -0600, ejc wrote:

<snip>

> Ok, please try the attached patch, with above options enabled
> (and leave the last patch applied).

It works great! Thank you for your help and time. If I can be of any
further assistance trying patches or providing core dumps, let me
know.

Thanks,
Eric

#8 Updated by dillon about 8 years ago

Please feel free to commit that patch any time. It won't interfere
with my buffer cache work!

-Matt

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