Re: [PATCH x86_64] Live Patching Function on 2.6.11.7

From: Chris Friesen
Date: Mon Apr 18 2005 - 01:36:48 EST


Chris Wedgwood wrote:
On Mon, Apr 18, 2005 at 01:19:57PM +0900, Takashi Ikebe wrote:


From our experience, sometimes patches became to dozens to hundreds
at one patching, and in this case GDB based approach cause target
process's availability descent.

could you perhaps explain some *real* *world* applications/systems
where this is necessary and why existing APIs won't work with them
perhaps?

In the telecom space it's quite common to want to modify multiple running binaries with as little downtime as possible. (Beyond a threshold it becomes FCC-reportable in the US, and everyone wants to avoid that...)

Our old proprietary OS had explicit support for replacing running binary code on the fly, so customers have gotten used to the ability. Now they want equivalent functionality with our linux-based stuff.

We've done some proprietary stuff (ie. pre-OSDL CGL) in this area, but it was apparently a real pain and was quite restrictive on the application writers. (I was not involved with that portion of the project.)

For general application support I suspect some kernel support will be required. Whether this is the way to go or whether it can be done using existing mechanisms, I'm not knowledgeable enough to comment.

Chris
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