Some googling found a patch which seems to have worked around the
"status = 256" problem. (I'm hoping that the patch is correct):
However, now I'm seeing the "enclosing" UML instance crash when I try to
run nested. The error is:
EXT3-fs: mounted filesystem with ordered data mode.
VFS: Mounted root (ext3 filesystem) readonly.
Eeek! page_mapcount(page) went negative! (-1)
page pfn = 14f
page->flags = 400
page->count = 1
page->mapping = 00000000
vma->vm_ops = 0x8205524
vma->vm_ops->fault = special_mapping_fault+0x0/0x44
Kernel panic - not syncing: Kernel mode signal 4
I've been googling on this, and the closest I've come (not sure it if is
related) was from last September. Sounded like Jeff understood the
problem, and was working on a patch:
Please, can somebody at least tell me if this path is worth pursuing?
Are other people using nesting and having it work??? I'd prefer to use
UML, but I don't want to waste my time pursuing something that it's
ready to use.
Russell Lewis wrote:
> Welcome, all. I played with UML a few years back (before it was in the
> mainline), and now plan to use it again for some academic research. I'm
> sure you guys will be hearing from me over the next couple of semesters. :)
> 3 early questions:
> - Is nesting currently working? Do we still need to set NESTING=x, or
> is it autodetected somehow?
> (I tried to nest, and it doesn't segfault, but it terminates immediately
> with "Checking syscall emulation patch for ptrace...check_sysemu :
> expecting SIGTRAP, got status = 256"
> - Is there a recommended "best" level to work from? I am currently
> using linux-2.6.28, which seems to work except or the "sigprocmask" problem.
> - Looks to me like the website is way out of date. Is there a good,
> current page or wiki where I can look things up? I've google'd a lot,
> but everything seems a couple of years old.
> Russ Lewis
> Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA
> -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise
> -Strategies to boost innovation and cut costs with open source participation
> -Receive a $600 discount off the registration fee with the source code: SFAD
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