Messages in this thread | | | From | Pedro Alves <> | Subject | Re: [RFC][PATCH 0/3] fork: Add the ability to create tasks with given pids | Date | Tue, 22 Nov 2011 12:04:38 +0000 |
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On Tuesday 22 November 2011 11:11:02, Pavel Emelyanov wrote: > > Can't we for now allow this for root and then later allow CAP_CHECKPOINT > > that Cyrill suggested? Or do we want to allow setting pids even w/o CR > > for NS creator? > > I think that systemd guys can play with it. E.g. respawning daemons with predefined > pids sounds like an interesting thing to play with.
This whole userspace C/R stuff and being able to set the child's pid has potential of being very useful for GDB too, allowing a much better reimplementation of its old checkpointing feature [*], and allowing for a faster reverse debugging implementation, by being able to do faster rewinding -- restore snapshot and replay instructions up to N (by single stepping or running to breakpoint), rather than manually undoing the effects of each instruction, one by one.
IOW, root only would be a shame from GDB's perspective.
[*] GDB has an old checkpointing feature ("checkpoint; info checkpoints" commands) based on forcing the tracee to fork, and holding on the fork child behind the scenes as a checkpoint. To restore the debugging state to a previous checkpoint, gdb swaps the current debuggee for the fork child as transparently for the user as was possible. Obviously this has a bunch of limitations and downsides like only working on non-threaded programs, and the inferior's pid changing...
-- Pedro Alves
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