[PATCH 1/9] doc: Update stallwarn.rst based on RCU Tasks Trace as SRCU
From: Paul E. McKenney
Date: Fri Sep 18 2026 - 20:32:27 EST
Now that RCU Tasks Trace has been re-implemented in terms of SRCU,
update stallwarn.rst to remove obsolete verbiage about RCU Tasks Trace
stall warnings.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
Documentation/RCU/stallwarn.rst | 22 +++++++++-------------
1 file changed, 9 insertions(+), 13 deletions(-)
diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst
index d7c8eff63317..a986358a5c27 100644
--- a/Documentation/RCU/stallwarn.rst
+++ b/Documentation/RCU/stallwarn.rst
@@ -122,10 +122,11 @@ warnings:
of RCU CPU stall warnings, eventually leading to the realization
that the CPU had failed.
-The RCU, RCU-sched, RCU-tasks, and RCU-tasks-trace implementations have
-CPU stall warning. Note that SRCU does *not* have CPU stall warnings.
-Please note that RCU only detects CPU stalls when there is a grace period
-in progress. No grace period, no CPU stall warnings.
+The RCU and RCU-tasks implementations have CPU stall warning. Note that
+SRCU does *not* have CPU stall warnings, and now that RCU-tasks-trace
+is implemented in terms of SRCU, neither does it. Please note that
+RCU only detects CPU stalls when there is a grace period in progress.
+No grace period, no CPU stall warnings.
To diagnose the cause of the stall, inspect the stack traces.
The offending function will usually be near the top of the stack.
@@ -213,21 +214,16 @@ RCU_STALL_RAT_DELAY
rcupdate.rcu_task_stall_timeout
-------------------------------
- This boot/sysfs parameter controls the RCU-tasks and
- RCU-tasks-trace stall warning intervals. A value of zero or less
- suppresses RCU-tasks stall warnings. A positive value sets the
- stall-warning interval in seconds. An RCU-tasks stall warning
- starts with the line:
+ This boot/sysfs parameter controls the RCU-tasks stall warning
+ interval. A value of zero or less suppresses RCU-tasks stall
+ warnings. A positive value sets the stall-warning interval
+ in seconds. An RCU-tasks stall warning starts with the line:
INFO: rcu_tasks detected stalls on tasks:
And continues with the output of sched_show_task() for each
task stalling the current RCU-tasks grace period.
- An RCU-tasks-trace stall warning starts (and continues) similarly:
-
- INFO: rcu_tasks_trace detected stalls on tasks
-
Interpreting RCU's CPU Stall-Detector "Splats"
==============================================
--
2.40.1