On 2023-05-18 15:07, Brian Hutchinson wrote:
[...]
If you attach to an ELF symbol (function), then there is no USDT in
play, so it should not be related to the issue you have.
That is what I was thinking which is why I wanted to try it.
But if your functions happen to be inlined, then there will be nothing
to attach to. Perhaps this is what happens there ?
I don't see any evidence of anything being inlined in this module. I
grepped the code to verify.
Back to being stumped/stuck.
Make sure to check the resulting assembler and ELF symbol tables.
The compiler is free to inline various functions unless they are
explicitly marked as __attribute__((noinline)). Also, if LTO is enabled,
further optimization can be done at link-time.
One purpose of the UST tracepoints is to be less fragile with respect to
specific optimizations done by the compiler and linker, thus
guaranteeing that whatever is instrumented with a tracepoint is indeed
available for tracing.
Also, double-check that the path you pass to --userspace-probe really
targets your executable or .so binary file, and is not just a symbolic link.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
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