Re: [PATCH x86_64] Live Patching Function on 2.6.11.7

From: Takashi Ikebe
Date: Mon Apr 25 2005 - 20:50:10 EST


I think that's the common sense in every carrier.
If we reboot the switch, the service will be disrupted.
The phone network is lifeline, and does not allow to be disrupt by just bug fix.
I think same kind of function is needed in many real enterprise/mission-critical/business area.

All do with ptrace may affect target process's time critical task. (need to stop target process whenever fix)
All implement in user application costs too much, need to implement all the application...(and I do not know this approach really works on time critical applications yet.)
There are clear demand to realize this common and GPL-ed function....

Valdis.Kletnieks@xxxxxx wrote:
On Mon, 25 Apr 2005 19:39:51 +0900, Takashi Ikebe said:


Unfortunately, we carrier have very many exiting software and try to run
on Linux.
We need to seek the way which can apply to exiting software also...


You *really* want to take the time to re-write the software to do things
The Linux Way. If you're looking at doing on-the-fly patching, you're
probably also carrying around a lot of *other* ugly cruft to make this
creeping horror work on Linux. In fact, I'd not be surprised if you have
a shim layer to make the compatibility layer for the *previous* system
work on Linux...

I'm reminded of a (possibly apocryphal) quote from an ATT spokesperson from
1988 or so, when a misplaced comma in a patch kept crashing the long-distance
phone network. When asked "Why don't you just reboot the affected switches?"
his response was "This assumes that the switch had ever been booted in the
first place". (Apparently, the *whole thing* had been on-the-fly replaced/patched
without an actual reload happening...)

Gaaahhh! :)


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