On Tue, Jan 19, 2010 at 09:47:45AM -0800, Jim Keniston wrote: > > Do you have plans for a variant > > that's completely in userspace? > > I don't know of any such plans, but I'd be interested to read more of > your thoughts here. As I understand it, you've suggested replacing the > probed instruction with a jump into an instrumentation vma (the XOL > area, or something similar). Masami has demonstrated -- through his > djprobes enhancement to kprobes -- that this can be done for many x86 > instructions. > > What does the code in the jumped-to vma do? Is the instrumentation code > that corresponds to the uprobe handlers encoded in an ad hoc .so?
Once the instrumentation is requested by a process that is not the instrumented one, this looks impossible to set a uprobe without a minimal voluntary collaboration from the instrumented process (events sent through IPC or whatever). So that looks too limited, this is not anymore a true dynamic uprobe.
