On Wednesday 06 April 2005 19:20, Jim Carter wrote: > On Tue, 5 Apr 2005, Rus Foster wrote: > > I've just compiled up a 2.4.29 guest kernel and having a problem that is > > typing "reboot" the guest does more of a power off than a reboot. Anyone > > got a fix for this? > > I saw the same thing in 2.6.8 host & guest, from the SuSE distro. He's speaking about the "guest" doing a poweroff rather than reboot, so guess it's different. However, I'm answering to you. > If you > run your UML as root, when the system call for shutdown/reboot is given, > it is executed faithfully by taking a flying leap into the BIOS, never to > return. When not as root, permission is denied, and the kernel does other > more reasonable things like exiting. > > I didn't investigate very thoroughly, but it looks like the host > architecture specific shutdown code is supposed to be omitted in UML, but > isn't, at least for you and me. Someone else complained that UML shutdown shut off his disks when UML was run as root.
Actually, the fact is that some BIOS interaction might be bundled in userspace code (think of hdparm). Uml shouldn't provide any way to execute the iopl() syscalls, but maybe it does. Even because, it was shown that there were some ways to escape on the host from the UML guest. It was regarded as a security issue, since the escape program must be written for this purpose. Instead, maybe it happens even normally and happened to you. Test 2.6.11-bs1 and/or 2.6.9-bs7, which contain the fixes for the mentioned "security" problems (and are much more stable than 2.6.8), please. Thanks -- Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
