WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] segfault bug in xeno-unstable...

To: sven.kretzschmar@xxxxxx
Subject: Re: [Xen-devel] segfault bug in xeno-unstable...
From: Ian Pratt <Ian.Pratt@xxxxxxxxxxxx>
Date: Mon, 13 Oct 2003 08:47:52 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxxx, Keir.Fraser@xxxxxxxxxxxx, Ian.Pratt@xxxxxxxxxxxx
Delivery-date: Mon, 13 Oct 2003 08:48:12 +0100
Envelope-to: steven.hand@xxxxxxxxxxxx
In-reply-to: Your message of "Mon, 13 Oct 2003 00:30:23 +0200." <3647.1065997823@xxxxxxxxxxxx>
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
 
> The actual version of xeno-unstable (Changeset 1.506) segfaults with some
> standard commands - at least with my 
> RedHat V8 (I haven't tested RedHat V9 yet) installation.
> If you enter "vi" or "vim" or "rpm -qa" as root or non-root user,
> xeno-linux just segfaults with no further comments (the next line of
> output just shows "Segmentation fault", nothing more).
> After a lot of tests with bk pull and bk undo, I was able to find out,
> that this bug was introduced with Changeset 1.478. 

Oops. 

I've just tried "rpm -qa" and "vi" under 1.506 on a RH7.2
installation, and it seems to work. I'll try setting up a RH8
install and retrying. My guess is that this is something to do
with our per-domain ldt switching code. The pthreads library uses
fs/gs for accessing thread local storage, and the exact mechanism
seems to change with every libc and RH version. However, its not
clear that rpm and vi use pthreads.

1.478 was a major change, so I'm not entirely
surprised. Shouldn't be hard to fix, though.
 
> BTW: Especially for production use, it would be nicer if xen could
> somehow pass up "printk"-output in xen to dom0's kernel logger,
> so that you don't need to configure and run a second machine for
> the serial line debug output all the time. While checking the segfault
> bug, I have not connected a debug machine to the serial line, so I
> don't know if it would have showed something helpful :-(

Yes, having Xen output (including boot messages) passed up to
domain0 would certainly be helpful. 
Just writing into a ring buffer and then mapping it from dom0
and having a daemon dump it to syslog should work. Might be worth
looking to see how klogd does it.

 > Another thing I realized while compiling and trying to load the 
> HyperSCSI kernel module:
> When loading the HyperSCSI client kernel module (which was 
> compiled against xeno-linux), it complains about 2 undefined 
> Kernel Symbols:
> 
> do_hypervisior_callback      and
> HYPERVISOR_shared_info
> 
> After adding 2 EXPORT_SYMBOL lines for these symbols in
> ../arch/xeno/kernel/i386_ksyms.c and
> recompiling the kernel, everything loaded and worked OK. 
> I hope it was not against xen design principles to add the
> 2 EXPORT_SYMBOL lines ;-)

We generally don't use modules much, so I'm afraid we hadn't
spotted this. We'll add the exports into the master tree, thanks.
 
> Regards + many thanks to the Xen project team for this nice 
> and professional software :))

Thanks.

Ian



-------------------------------------------------------
This SF.net email is sponsored by: SF.net Giveback Program.
SourceForge.net hosts over 70,000 Open Source Projects.
See the people who have HELPED US provide better services:
Click here: http://sourceforge.net/supporters.php
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel

<Prev in Thread] Current Thread [Next in Thread>