Re: [uml-devel] [mgedmin@b4net.lt: Bug#256873: user-mode-linux: fails to start (kernel panic)]

[Stefan Gybas <sgybas@debian.org>]

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Matt Zimmerman wrote:

> I am receiving many reports from my users that 2.4.26-1um is less functional
> than past versions, especially (but not exclusively) where hostfs is
> concerned.  Are others experiencing problems as well?  I am considering
> reverting the Debian packages to 2.4.24-1um, which was the last version
> which was stable for me (it had only one frustrating hostfs bug, where
> readdir() would read forever).

That's also my experince: I'm currently running Linux 2.4.26 with UML 
patch 2.4.24-1 on a production system (kernel 2.6 with SKAS patch on the 
host) without major problems.

When I used UML patch 2.4.24-2 or higher the guest systems were very 
unstable and crashed after a few hours. The linux processes on the host 
were simply killed by a segmentation fault or I got one of these error 
messages:

Kernel panic: Segfault with no mm
Kernel panic: switch_mm_skas - PTRACE_SWITCH_MM failed, errno = 0

I even tried to build a UML kernel on woody (where the AIO glibc headers 
are not available, so the kernel is built with gcc 2.95 and without AIO 
support) but the resulting kernel also was not very stable.

So I suggest to use kernel 2.4.26 (or higher, when available) with UML 
patch 2.4.24-1 for the user-mode-linux Debian package (which is also 
used by some commercial hosting services like Linode). BTW, thanks for 
packaging!

Stefan

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