Messages in this thread | | | Date | Tue, 24 Feb 2015 11:25:45 +0100 | From | Ingo Molnar <> | Subject | Re: live kernel upgrades (was: live kernel patching design) |
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* Pavel Machek <pavel@ucw.cz> wrote:
> > More importantly, both kGraft and kpatch are pretty limited > > in what kinds of updates they allow, and neither kGraft nor > > kpatch has any clear path towards applying more complex > > fixes to kernel images that I can see: kGraft can only > > apply the simplest of fixes where both versions of a > > function are interchangeable, and kpatch is only marginally > > better at that - and that's pretty fundamental to both > > projects! > > > > I think all of these problems could be resolved by shooting > > for the moon instead: > > > > - work towards allowing arbitrary live kernel upgrades! > > > > not just 'live kernel patches'. > > Note that live kernel upgrade would have interesting > implications outside kernel: > > 1) glibc does "what kernel version is this?" caches > result and alters behaviour accordingly.
That should be OK, as a new kernel will be ABI compatible with an old kernel.
A later optimization could update the glibc cache on an upgrade, fortunately both projects are open source.
> 2) apps will do recently_introduced_syscall(), get error > and not attempt it again.
That should be fine too.
Thanks,
Ingo
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