tracing: Add an option to show symbols in _text+offset for function profiler

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Function profiler shows the hit count of each function using its symbol
name. However, there are some same-name local symbols, which we can not
distinguish.
To solve this issue, this introduces an option to show the symbols
in "_text+OFFSET" format. This can avoid exposing the random shift of
KASLR. The functions in modules are shown as "MODNAME+OFFSET" where the
offset is from ".text".

E.g. for the kernel text symbols, specify vmlinux and the output to
 addr2line, you can find the actual function and source info;

  $ addr2line -fie vmlinux _text+3078208
  __balance_callbacks
  kernel/sched/core.c:5064

for modules, specify the module file and .text+OFFSET;

  $ addr2line -fie samples/trace_events/trace-events-sample.ko .text+8224
  do_simple_thread_func
  samples/trace_events/trace-events-sample.c:23

Link: https://lore.kernel.org/all/176187878064.994619.8878296550240416558.stgit@devnote2/

Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

...

This commit is contained in:

Masami Hiramatsu (Google) 2025-10-31 11:46:20 +09:00

parent bbec8e28ca

commit 1149fcf759

3 changed files with 38 additions and 4 deletions

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26

kernel/trace/ftrace.c

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5

kernel/trace/trace.c

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11

kernel/trace/trace.h

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