Re: [PATCH v3] xen/hvm: add kexec/kdump support

[Olaf Hering <olaf@aepfle.de>]

On Mon, Aug 01, Olaf Hering wrote:

> - add xs_introduce() in xs_init() to shutdown all open watches that the
>   previous kernel had registered. Without this change the kexec may
>   crash due to unexpected watch events.
>   This depends on a xenstored change which has to allow the XS_INTRODUCE
>   from a guest.
>   And this part may need more work because the xs_introduce may hang
>   forever on an old dom0 tool stack

The hang I encountered last week was due to a bug in the new
xs_introduce() function. "iov[2].iov_len" was by accident written as
"iov[3].iov_len", which left the iov_len uninitialized. Then xenstored
got a huge iov_len, returned an error which the kernel received. But the
process_msg() did not wakeup read_reply() for some reason.


Today an unmodified sles11sp1 dom0 can boot a 3.0 kernel with the
kexec/kdump patch applied.

Olaf