Uprobes: not quite there yet [LWN.net]

Uprobes: not quite there yet

Posted Jan 21, 2010 16:45 UTC (Thu) by bronson (subscriber, #4806)
Parent article: Uprobes: not quite there yet

Suddenly I'm reading the project's name as UpRobes. That might be even more descriptive. :)

Can anyone name an existing app that might break with the foreign memory area in its address space? Based on this article, the complaints about XOL sound awfully obscure.

Adding an emulator to the kernel just for this?? That would be an endless source of problems!

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Uprobes: not quite there yet

Posted Feb 17, 2010 19:14 UTC (Wed) by oak (subscriber, #2786) [Link]

Even the SSOL approach one needs to "emulate" / "fix" those of the
instructions which use relative addressing, see Roland's old mail on the
subject:
http://sourceware.org/ml/systemtap/2007-q1/msg00571.html

And the instructions are of course architecture specific.

The good thing is that if one puts breakpoints just on function entry &
exit points, those usually use fairly small set of instructions. See e.g.
this user-space function tracing utility that uses SSOL with breakpoints:
http://repository.maemo.org/pool/fremantle/free/f/functra...

If breakpoints can be put anywhere, it's more of an issue. Good question
is how to test that emulation of all the required instructions for SSOL
works fine...