[Crash-utility] [PATCH 0/7] Upgrade the remote access to a xen domain.

[Don Slutz]

On 11/19/13 07:51, Daniel Kiper wrote:
> On Tue, Nov 19, 2013 at 06:46:39AM -0500, Don Slutz wrote:
>> From: Don Slutz <dslutz at verizon.com>
>>
>> Currently crash 4.0 and later using the code:
>>
>> http://lists.xen.org/archives/html/xen-devel/2013-11/msg02569.html
>>
>> There is some very limited documention on crashes remote ptotocol in:
>>
>> http://lists.xen.org/archives/html/xen-devel/2013-11/msg02352.html
>>
>> and some fixes in the attachment 0001-xen-crashd-Connect-crash-with-domain.patch
>> from the 1st link above.
>>
>> How ever there are issues with the current code:
>>
>> 1) The remote protocol has a minor issue (which I have not been able to
>>     happen) based on the fact TCP/IP is stream based protocol.  This means
>>     a RECV or a SEND may not do the fully requested size of data.  In fact
>>     the current code assumes that the amount of data that a SEND is called
>>     with will all be read with a single RECV.
>>
>> 2) The most common mismatch between crash and older kernels is
>>     phys_base.  In the remote case, see if the remote server supports
>>     vitrual memory access, and if so, see if phys_base can be retreived.
>>
>> 3) crash assumes that the remote system is active and can not return
>>     currect IP and SP to do a better back trace.
>>
>> 4) enable a non-active mode of remote access.
>>
>> This patch set attempts to fix these:
>>
>> The fix for #1 I have called NIL mode (patch 1).
>> The fix for #2 uses get_remote_phys_base (patch 3).
>> The fix for #3 uses get_remote_regs (patch 5).
>> The fix for #4 uses special file /dev/xenmem (patch 7).
> Where is this file created? In guest or in host. Is it done by udev?
> Where is driver for this file?
This is a fake file, it only exists in xen-crashd.
>>    It also REMOTE_NIL() to indicate "remote paused system".
>>
>> Don Slutz (7):
>>    Add NIL mode to remote.
>>    remote_proc_version: NULL terminate passed buffer on error.
>>    Add get_remote_phys_base.
>>    Add remote_vtop.
>>    bt: get remote live registers if possible.
>>    Add get_remote_cr3
>>    Add support for non-live remote.
>>
>>   defs.h   |   8 +-
>>   kernel.c |  25 +++-
>>   memory.c |  25 +++-
>>   remote.c | 462 +++++++++++++++++++++++++++++++++++++++++++++++++++++----------
>>   x86_64.c |  24 ++++
>>   5 files changed, 465 insertions(+), 79 deletions(-)
> I have done quick review. It looks quite nice. There are two nitpicks
> for me. Please do not use camelCase (I have found one in patch 3 in
> struct _remote_context) and do not add Emacs directives at the end
> of files (this is Xen specific stuff).
I will try and remove all camelCase.
I can remove the emacs stuff, but I know it saves me time.   This is because of:

  * c-basic-offset: 8
  * indent-tabs-mode: t

Where as Xen:

  * c-basic-offset: 4
  * indent-tabs-mode: nil

So my default is the Xen one not the crash one.
    -Don Slutz

> Daniel