Merge tag 'rcu.next.v6.10' of https://github.com/urezki/linux

Pull RCU updates from Uladzislau Rezki:

 - Fix a lockdep complain for lazy-preemptible kernel, remove redundant
   BH disable for TINY_RCU, remove redundant READ_ONCE() in tree.c, fix
   false positives KCSAN splat and fix buffer overflow in the
   print_cpu_stall_info().

 - Misc updates related to bpf, tracing and update the MAINTAINERS file.

 - An improvement of a normal synchronize_rcu() call in terms of
   latency. It maintains a separate track for sync. users only. This
   approach bypasses per-cpu nocb-lists thus sync-users do not depend on
   nocb-list length and how fast regular callbacks are processed.

 - RCU tasks: switch tasks RCU grace periods to sleep at TASK_IDLE
   priority, fix some comments, add some diagnostic warning to the
   exit_tasks_rcu_start() and fix a buffer overflow in the
   show_rcu_tasks_trace_gp_kthread().

 - RCU torture: Increase memory to guest OS, fix a Tasks Rude RCU
   testing, some updates for TREE09, dump mode information to debug GP
   kthread state, remove redundant READ_ONCE(), fix some comments about
   RCU_TORTURE_PIPE_LEN and pipe_count, remove some redundant pointer
   initialization, fix a hung splat task by when the rcutorture tests
   start to exit, fix invalid context warning, add '--do-kvfree'
   parameter to torture test and use slow register unregister callbacks
   only for rcutype test.

* tag 'rcu.next.v6.10' of https://github.com/urezki/linux: (48 commits)
  rcutorture: Use rcu_gp_slow_register/unregister() only for rcutype test
  torture: Scale --do-kvfree test time
  rcutorture: Fix invalid context warning when enable srcu barrier testing
  rcutorture: Make stall-tasks directly exit when rcutorture tests end
  rcutorture: Removing redundant function pointer initialization
  rcutorture: Make rcutorture support print rcu-tasks gp state
  rcutorture: Use the gp_kthread_dbg operation specified by cur_ops
  rcutorture: Re-use value stored to ->rtort_pipe_count instead of re-reading
  rcutorture: Fix rcu_torture_one_read() pipe_count overflow comment
  rcutorture: Remove extraneous rcu_torture_pipe_update_one() READ_ONCE()
  rcu: Allocate WQ with WQ_MEM_RECLAIM bit set
  rcu: Support direct wake-up of synchronize_rcu() users
  rcu: Add a trace event for synchronize_rcu_normal()
  rcu: Reduce synchronize_rcu() latency
  rcu: Fix buffer overflow in print_cpu_stall_info()
  rcu: Mollify sparse with RCU guard
  rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow
  rcu-tasks: Fix the comments for tasks_rcu_exit_srcu_stall_timer
  rcu-tasks: Replace exit_tasks_rcu_start() initialization with WARN_ON_ONCE()
  rcu: Remove redundant CONFIG_PROVE_RCU #if condition
  ...

1 files changed, 27 insertions, 0 deletions

diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 2ef9c719772a..31b3e0d3e65f 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -708,6 +708,33 @@ TRACE_EVENT_RCU(rcu_invoke_kfree_bulk_callback,
 );
 
 /*
+ * Tracepoint for a normal synchronize_rcu() states. The first argument
+ * is the RCU flavor, the second argument is a pointer to rcu_head the
+ * last one is an event.
+ */
+TRACE_EVENT_RCU(rcu_sr_normal,
+
+	TP_PROTO(const char *rcuname, struct rcu_head *rhp, const char *srevent),
+
+	TP_ARGS(rcuname, rhp, srevent),
+
+	TP_STRUCT__entry(
+		__field(const char *, rcuname)
+		__field(void *, rhp)
+		__field(const char *, srevent)
+	),
+
+	TP_fast_assign(
+		__entry->rcuname = rcuname;
+		__entry->rhp = rhp;
+		__entry->srevent = srevent;
+	),
+
+	TP_printk("%s rhp=0x%p event=%s",
+		__entry->rcuname, __entry->rhp, __entry->srevent)
+);
+
+/*
  * Tracepoint for exiting rcu_do_batch after RCU callbacks have been
  * invoked.  The first argument is the name of the RCU flavor,
  * the second argument is number of callbacks actually invoked,