reentrant probes

Frank Ch. Eigler fche@redhat.com
Thu May 5 14:39:00 GMT 2005


Hi Victoria -

On Thu, May 05, 2005 at 06:28:19PM +0400, Gromova, Victoria wrote:
> [...]
> Could it be possible & useful to defer probe handler execution to the
> later point instead of just skipping it? 

From the systemtap point of view, deferring nested kprobes would
probably not help.  That's because probe handlers may make references
to probe-site state like local variables, based on a snapshot of
registers given to the handlers.  By the time a deferred handler might
get called, even an archived snapshot will have data that is too
obsolete to use.  For example, stack frames will have been unwound.


- FChE
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