Merge tag 'trace-v6.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...

Merge tag 'trace-v6.11-rc4' of git://git./linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix adding a new fgraph callback after function graph tracing has
   already started.

   If the new caller does not initialize its hash before registering the
   fgraph_ops, it can cause a NULL pointer dereference. Fix this by
   adding a new parameter to ftrace_graph_enable_direct() passing in the
   newly added gops directly and not rely on using the fgraph_array[],
   as entries in the fgraph_array[] must be initialized.

   Assign the new gops to the fgraph_array[] after it goes through
   ftrace_startup_subops() as that will properly initialize the
   gops->ops and initialize its hashes.

 - Fix a memory leak in fgraph storage memory test.

   If the "multiple fgraph storage on a function" boot up selftest fails
   in the registering of the function graph tracer, it will not free the
   memory it allocated for the filter. Break the loop up into two where
   it allocates the filters first and then registers the functions where
   any errors will do the appropriate clean ups.

 - Only clear the timerlat timers if it has an associated kthread.

   In the rtla tool that uses timerlat, if it was killed just as it was
   shutting down, the signals can free the kthread and the timer. But
   the closing of the timerlat files could cause the hrtimer_cancel() to
   be called on the already freed timer. As the kthread variable is is
   set to NULL when the kthreads are stopped and the timers are freed it
   can be used to know not to call hrtimer_cancel() on the timer if the
   kthread variable is NULL.

 - Use a cpumask to keep track of osnoise/timerlat kthreads

   The timerlat tracer can use user space threads for its analysis. With
   the killing of the rtla tool, the kernel can get confused between if
   it is using a user space thread to analyze or one of its own kernel
   threads. When this confusion happens, kthread_stop() can be called on
   a user space thread and bad things happen. As the kernel threads are
   per-cpu, a bitmask can be used to know when a kernel thread is used
   or when a user space thread is used.

 - Add missing interface_lock to osnoise/timerlat stop_kthread()

   The stop_kthread() function in osnoise/timerlat clears the osnoise
   kthread variable, and if it was a user space thread does a put_task
   on it. But this can race with the closing of the timerlat files that
   also does a put_task on the kthread, and if the race happens the task
   will have put_task called on it twice and oops.

 - Add cond_resched() to the tracing_iter_reset() loop.

   The latency tracers keep writing to the ring buffer without resetting
   when it issues a new "start" event (like interrupts being disabled).
   When reading the buffer with an iterator, the tracing_iter_reset()
   sets its pointer to that start event by walking through all the
   events in the buffer until it gets to the time stamp of the start
   event. In the case of a very large buffer, the loop that looks for
   the start event has been reported taking a very long time with a non
   preempt kernel that it can trigger a soft lock up warning. Add a
   cond_resched() into that loop to make sure that doesn't happen.

 - Use list_del_rcu() for eventfs ei->list variable

   It was reported that running loops of creating and deleting kprobe
   events could cause a crash due to the eventfs list iteration hitting
   a LIST_POISON variable. This is because the list is protected by SRCU
   but when an item is deleted from the list, it was using list_del()
   which poisons the "next" pointer. This is what list_del_rcu() was to
   prevent.

* tag 'trace-v6.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()
  tracing/timerlat: Only clear timer if a kthread exists
  tracing/osnoise: Use a cpumask to know what threads are kthreads
  eventfs: Use list_del_rcu() for SRCU protected list variable
  tracing: Avoid possible softlockup in tracing_iter_reset()
  tracing: Fix memory leak in fgraph storage selftest
  tracing: fgraph: Fix to add new fgraph_ops to array after ftrace_startup_subops()