tracing/probes: Support typecast for various probe events

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Support BTF typecast feature on other probe events, but only if it is
kernel function entry or return, and must use function parameter name
or $retval. This means you can do:

  (STRUCT)PARAM->MEMBER

Note: you can not use other variables like $stackN, %reg etc. That
needs nesting support.

To support other probe events, we just need to use last_struct type
when we find a function parameter in parse_btf_arg().

This also updates <tracefs>/README file to show struct typecast.

Link: https://lore.kernel.org/all/178271362928.1176915.12235759508786922490.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

...

This commit is contained in:

Masami Hiramatsu (Google) 2026-07-02 21:12:40 +09:00

parent 777bcbd2ac

commit 438a8d6a82

5 changed files with 30 additions and 7 deletions

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3

Documentation/trace/fprobetrace.rst

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4

Documentation/trace/kprobetrace.rst

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2

kernel/trace/trace.c

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23

kernel/trace/trace_probe.c

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5

kernel/trace/trace_probe.h

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