Messages in this thread | | | Subject | Re: [RFC v7][PATCH 2/9] General infrastructure for checkpoint restart | From | Matt Helsley <> | Date | Mon, 27 Oct 2008 13:51:45 -0700 |
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On Mon, 2008-10-27 at 13:11 -0400, Oren Laadan wrote: > Dave Hansen wrote: > > On Mon, 2008-10-27 at 07:03 -0400, Oren Laadan wrote: > >>> In our implementation, we simply refused to checkpoint setid > >> programs. > >> > >> True. And this works very well for HPC applications. > >> > >> However, it doesn't work so well for server applications, for > >> instance. > >> > >> Also, you could use file system snapshotting to ensure that the file > >> system view does not change, and still face the same issue. > >> > >> So I'm perfectly ok with deferring this discussion to a later time :) > > > > Oren, is this a good place to stick a process_deny_checkpoint()? Both > > so we refuse to checkpoint, and document this as something that has to > > be addressed later? > > why refuse to checkpoint ?
If most setuid programs hold privileged resources for extended periods of time after dropping privileges then it seems like a good idea to refuse to checkpoint. Restart of those programs would be quite unreliable unless/until we find a nice solution.
> if I'm root, and I want to checkpoint, and later restart, my sshd server > (assuming we support listening sockets) - then why not ? > we can just let it be, and have the restart fail (if it isn't root that > does the restart); perhaps add something like warn_checkpoint() (similar > to deny, but only warns) ?
How will folks not specializing in checkpoint/restart know when to use this as opposed to deny?
Instead, how about a flag to sys_checkpoint() -- DO_RISKY_CHECKPOINT -- which checkpoints despite !may_checkpoint?
Cheers, -Matt Helsley
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