Merge tag 'trace-v6.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:
 "User events:

   - Use long instead of int for storing the enable set/clear bit, as it
     was found that big endian machines could end up using the wrong
     bits.

   - Split allocating mm and attaching it. This keeps the allocation
     separate from the registration and avoids various races.

   - Remove RCU locking around pin_user_pages_remote() as that can
     schedule. The RCU protection is no longer needed with the above
     split of mm allocation and attaching.

   - Rename the "link" fields of the various structs to something more
     meaningful.

   - Add comments around user_event_mm struct usage and locking
     requirements.

  Timerlat tracer:

   - Fix missed wakeup of timerlat thread caused by the timerlat
     interrupt triggering when tracing is off. The timer interrupt
     handler needs to always wake up the timerlat thread regardless if
     tracing is enabled or not, otherwise, it will never wake up.

  Histograms:

   - Fix regression of breaking the "stacktrace" modifier for variables.
     That modifier cannot be used for values, but can be used for
     variables that are passed from one histogram to the next. This was
     broken when adding the restriction to values as the variable logic
     used the same code.

   - Rename the special field "stacktrace" to "common_stacktrace".

     Special fields (that are not actually part of the event, but can
     act just like event fields, like 'comm' and 'timestamp') should be
     prefixed with 'common_' for consistency. To keep backward
     compatibility, 'stacktrace' can still be used (as with the special
     field 'cpu'), but can be overridden if the event has a field called
     'stacktrace'.

   - Update the synthetic event selftests to use the new name (synthetic
     events are created by histograms)

  Tracing bootup selftests:

   - Reorganize the code to keep artifacts of the selftests not compiled
     in when selftests are not configured.

   - Add various cond_resched() around the selftest code, as the
     softlock watchdog was triggering much more often. It appears that
     the kernel runs slower now with full debugging enabled.

   - While debugging ftrace with ftrace (using an instance ring buffer
     instead of the top level one), I found that the selftests were
     disabling prints to the debug instance.

     This should not happen, as the selftests only disable printing to
     the main buffer as the selftests examine the main buffer to see if
     it has what it expects, and prints can make the tests fail.

     Make the selftests only disable printing to the toplevel buffer,
     and leave the instance buffers alone"

* tag 'trace-v6.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Have function_graph selftest call cond_resched()
  tracing: Only make selftest conditionals affect the global_trace
  tracing: Make tracing_selftest_running/delete nops when not used
  tracing: Have tracer selftests call cond_resched() before running
  tracing: Move setting of tracing_selftest_running out of register_tracer()
  tracing/selftests: Update synthetic event selftest to use common_stacktrace
  tracing: Rename stacktrace field to common_stacktrace
  tracing/histograms: Allow variables to have some modifiers
  tracing/user_events: Document user_event_mm one-shot list usage
  tracing/user_events: Rename link fields for clarity
  tracing/user_events: Remove RCU lock while pinning pages
  tracing/user_events: Split up mm alloc and attach
  tracing/timerlat: Always wakeup the timerlat thread
  tracing/user_events: Use long vs int for atomic bit ops

2 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 0e373222a6df..7c4a0b72334e 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -806,6 +806,7 @@ enum {
 	FILTER_TRACE_FN,
 	FILTER_COMM,
 	FILTER_CPU,
+	FILTER_STACKTRACE,
 };
 
 extern int trace_event_raw_init(struct trace_event_call *call);
diff --git a/include/linux/user_events.h b/include/linux/user_events.h
index 2847f5a18a86..8afa8c3a0973 100644
--- a/include/linux/user_events.h
+++ b/include/linux/user_events.h
@@ -17,9 +17,10 @@
 
 #ifdef CONFIG_USER_EVENTS
 struct user_event_mm {
-	struct list_head	link;
+	struct list_head	mms_link;
 	struct list_head	enablers;
 	struct mm_struct	*mm;
+	/* Used for one-shot lists, protected by event_mutex */
 	struct user_event_mm	*next;
 	refcount_t		refcnt;
 	refcount_t		tasks;