Commit 01e9982a authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'trace-fixes-v3.17-rc1' of...

Merge tag 'trace-fixes-v3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull fix for ftrace function tracer/profiler conflict from Steven Rostedt:
 "The rewrite of the ftrace code that makes it possible to allow for
  separate trampolines had a design flaw with the interaction between
  the function and function_graph tracers.

  The main flaw was the simplification of the use of multiple tracers
  having the same filter (like function and function_graph, that use the
  set_ftrace_filter file to filter their code).  The design assumed that
  the two tracers could never run simultaneously as only one tracer can
  be used at a time.  The problem with this assumption was that the
  function profiler could be implemented on top of the function graph
  tracer, and the function profiler could run at the same time as the
  function tracer.  This caused the assumption to be broken and when
  ftrace detected this failed assumpiton it would spit out a nasty
  warning and shut itself down.

  Instead of using a single ftrace_ops that switches between the
  function and function_graph callbacks, the two tracers can again use
  their own ftrace_ops.  But instead of having a complex hierarchy of
  ftrace_ops, the filter fields are placed in its own structure and the
  ftrace_ops can carefully use the same filter.  This change took a bit
  to be able to allow for this and currently only the global_ops can
  share the same filter, but this new design can easily be modified to
  allow for any ftrace_ops to share its filter with another ftrace_ops.

  The first four patches deal with the change of allowing the ftrace_ops
  to share the filter (and this needs to go to 3.16 as well).

  The fifth patch fixes a bug that was also caused by the new changes
  but only for archs other than x86, and only if those archs implement a
  direct call to the function_graph tracer which they do not do yet but
  will in the future.  It does not need to go to stable, but needs to be
  fixed before the other archs update their code to allow direct calls
  to the function_graph trampoline"

* tag 'trace-fixes-v3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Use current addr when converting to nop in __ftrace_replace_code()
  ftrace: Fix function_profiler and function tracer together
  ftrace: Fix up trampoline accounting with looping on hash ops
  ftrace: Update all ftrace_ops for a ftrace_hash_ops update
  ftrace: Allow ftrace_ops to use the hashes from other ops
parents 7be141d0 39b5552c
......@@ -102,6 +102,15 @@ enum {
FTRACE_OPS_FL_DELETED = 1 << 8,
};
#ifdef CONFIG_DYNAMIC_FTRACE
/* The hash used to know what functions callbacks trace */
struct ftrace_ops_hash {
struct ftrace_hash *notrace_hash;
struct ftrace_hash *filter_hash;
struct mutex regex_lock;
};
#endif
/*
* Note, ftrace_ops can be referenced outside of RCU protection.
* (Although, for perf, the control ops prevent that). If ftrace_ops is
......@@ -121,10 +130,9 @@ struct ftrace_ops {
int __percpu *disabled;
#ifdef CONFIG_DYNAMIC_FTRACE
int nr_trampolines;
struct ftrace_hash *notrace_hash;
struct ftrace_hash *filter_hash;
struct ftrace_ops_hash local_hash;
struct ftrace_ops_hash *func_hash;
struct ftrace_hash *tramp_hash;
struct mutex regex_lock;
unsigned long trampoline;
#endif
};
......
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