Profiling Kernel function blocks

[Frank Ch. Eigler]

Domenico Di Leo <domenico.dileo@unina.it> writes:

> [...]
> In other words, when I run the following script
> probe kernel.function("*@kernel/*.c").return{
>     printf("%s  %s", threadindent(-1),probefunc());
> }
> the entire OS gets stuck.
> [...]

Several parts of the kernel are not capable of tolerating kprobes in
various places.  While mjw is right to point to our PR2725, as far as
we know, these are long-standing kernel (rather than systemtap) bugs
that LKML has not been able (or find time?) to solve.

Our normal suggestion is to try later rather than earlier kernel and
systemtap versions, and limit wildcarded probes like that to smaller
and less-sensitive sections of the kernel.

- FChE