ftrace_direct_func_count ?

["Dr. David Alan Gilbert" <dave@treblig.org>]

Hi,
  I've just posted a patch 'ftrace: Remove unused list 'ftrace_direct_funcs''
that clears out some old code, but while at it I noticed the global
'ftrace_direct_func_count'.

As far as I can tell, it's never assigned (or initialised) but it is tested:

kernel/trace/fgraph.c:
#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
  /*
   * Skip graph tracing if the return location is served by direct trampoline,
   * since call sequence and return addresses are unpredictable anyway.
   * Ex: BPF trampoline may call original function and may skip frame
   * depending on type of BPF programs attached.
   */
  if (ftrace_direct_func_count &&
      ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE))
    return -EBUSY;
#endif

So I wasn't sure whether it was just safe to nuke that section
or whether it really needed fixing?

Dave

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