Merge tag 'trace-v5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix deadloop in ring buffer because of using stale "read" variable

 - Fix synthetic event use of field_pos as boolean and not an index

 - Fixed histogram special var "cpu" overriding event fields called
   "cpu"

 - Cleaned up error prone logic in alloc_synth_event()

 - Removed call to synchronize_rcu_tasks_rude() when not needed

 - Removed redundant initialization of a local variable "ret"

 - Fixed kernel crash when updating tracepoint callbacks of different
   priorities.

* tag 'trace-v5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracepoints: Update static_call before tp_funcs when adding a tracepoint
  ftrace: Remove redundant initialization of variable ret
  ftrace: Avoid synchronize_rcu_tasks_rude() call when not necessary
  tracing: Clean up alloc_synth_event()
  tracing/histogram: Rename "cpu" to "common_cpu"
  tracing: Synthetic event field_pos is an index not a boolean
  tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop.

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f8b80b5bab71..c59dd35a6da5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5609,6 +5609,10 @@ static const char readme_msg[] =
 	"\t            [:name=histname1]\n"
 	"\t            [:<handler>.<action>]\n"
 	"\t            [if <filter>]\n\n"
+	"\t    Note, special fields can be used as well:\n"
+	"\t            common_timestamp - to record current timestamp\n"
+	"\t            common_cpu - to record the CPU the event happened on\n"
+	"\n"
 	"\t    When a matching event is hit, an entry is added to a hash\n"
 	"\t    table using the key(s) and value(s) named, and the value of a\n"
 	"\t    sum called 'hitcount' is incremented.  Keys and values\n"