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Re: [Xen-devel] xend segfaults when starting

On Wed, 2010-08-18 at 17:02 +0100, Christoph Egger wrote:
> > > hcall_buf itself has the address 0x7f7ffdfe7000.
> > >
> > > hcall_buf->buf has the address 0x7f7ffdfe7040.
> >
> > That's very odd -- hcall_buf->buf is allocated with xc_memalign and
> > therefore should be page aligned. Are you sure the addresses aren't
> the
> > other way round?
> Yes, I am. 

Then NetBSD has a bug where it apparently returns non-page aligned
allocations from valloc.

> Calling _xc_clean_hcall_buf() unconditionally and hcall_buf_prep()
> conditionally sounds to me like calling free() unconditionally
> and malloc() conditionally.

Not quite because (in the updated patch) _xc_clean_hcall_buf()
effectively contains a check to see if hcall_buf_prep() has been called.
IOW it is OK for the same reason free(NULL) is OK.

> Is it possible that xend can call xc_interface_close() during startup
> and hcall_buf_prep() later when xend comes in interaction with xm ?

Yes, but this is safe.


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