On Wed, 14 Feb 2024 21:55:03 +0100 Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > Masami, > we recently discussed the possibility to store data between entry/return probe, > IIUC your current patchset [0] allows that, but it seems to be shared across all > the tracers for the given function (__ftrace_return_to_handler).. is the plan to > make the shadow stack per tracer and function? /cc Steven The shadow stack is per task, but it saves unique data per tracer per function. It allows up to 16 different tracers attached to function graph tracing at a time, as there is a limited shadow stack size, which all the attached tracers use. Now you can create your own shadow stack per user (bpf program?) and have a single registered function graph user that will demux the data coming in and out of the function. -- Steve
