Serge E. Hallyn wrote: > Quoting Greg Kurz (gkurz@xxxxxxxxxx): >> On Fri, 2009-03-06 at 01:00 +0300, Alexey Dobriyan wrote: >>> On Thu, Mar 05, 2009 at 01:27:07PM -0800, Dave Hansen wrote: >>>>> Imagine, unsupported file is opened between userspace checks >>>>> for /proc/*/checkpointable and /proc/*/fdinfo/*/checkpointable >>>>> and whatever, you stil have to do all the checks inside checkpoint(2). >>>> Alexey, we have two problems here. I completely agree that we have to >>>> do complete and thorough checks of each file descriptor at >>>> sys_checkpoint(). Any checks made at other times should not be trusted. >>>> >>>> The other side is what Ingo has been asking for. How do we *know* when >>>> we are checkpointable *before* we call (and without calling) >>> This "without calling checkpoint(2)" results in much complications >>> as demonstrated. >>> >>> task_struct and file are not like other structures because they are exposed >>> in /proc. For PROC_FS=n kernels, one can't even check. >>> >>> You can do checkpoint(2) without actual dump. You pass, you're most >>> certainly checkpointable (with inevitable race condition in mind). >>> >> Ahhh thank you very much Alexey ! I wanted to explain this to Dave a few >> monthes ago but I failed... probably because of my poor English skills. >> >> https://lists.linux-foundation.org/pipermail/containers/2008-October/013549.html >> >> Why would we add checking all over the place when it MUST be done on the >> sys_checkpoint() path ? The checkpoint(2) dry-run is definitely the way >> to go. > > I'm sure Dave understood that this was possible :) > > But what you and Alexey are proposing does not and cannot fullfill > Ingo's requirement. And if Ingo's requirement is fulfilled, would any C/R patchset be acceptable ? C. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
