Merge tag 'rcu.2026.03.31a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

Pull RCU updates from Joel Fernandes:
 "NOCB CPU management:

   - Consolidate rcu_nocb_cpu_offload() and rcu_nocb_cpu_deoffload() to
     reduce code duplication

   - Extract nocb_bypass_needs_flush() helper to reduce duplication in
     NOCB bypass path

  rcutorture/torture infrastructure:

   - Add NOCB01 config for RCU_LAZY torture testing

   - Add NOCB02 config for NOCB poll mode testing

   - Add TRIVIAL-PREEMPT config for textbook-style preemptible RCU
     torture

   - Test call_srcu() with preemption both disabled and enabled

   - Remove kvm-check-branches.sh in favor of kvm-series.sh

   - Make hangs more visible in torture.sh output

   - Add informative message for tests without a recheck file

   - Fix numeric test comparison in srcu_lockdep.sh

   - Use torture_shutdown_init() in refscale and rcuscale instead of
     open-coded shutdown functions

   - Fix modulo-zero error in torture_hrtimeout_ns().

  SRCU:

   - Fix SRCU read flavor macro comments

   - Fix s/they disables/they disable/ typo in srcu_read_unlock_fast()

  RCU Tasks:

   - Document that RCU Tasks Trace grace periods now imply RCU grace
     periods

   - Remove unnecessary smp_store_release() in cblist_init_generic()"

* tag 'rcu.2026.03.31a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux:
  rcutorture: Test call_srcu() with preemption disabled and not
  rcu: Add BOOTPARAM_RCU_STALL_PANIC Kconfig option
  torture: Avoid modulo-zero error in torture_hrtimeout_ns()
  rcu/nocb: Extract nocb_bypass_needs_flush() to reduce duplication
  rcu/nocb: Consolidate rcu_nocb_cpu_offload/deoffload functions
  rcu-tasks: Remove unnecessary smp_store_release() in cblist_init_generic()
  rcutorture: Add NOCB02 config for nocb poll mode testing
  rcutorture: Add NOCB01 config for RCU_LAZY torture testing
  rcu-tasks: Document that RCU Tasks Trace grace periods now imply RCU grace periods
  srcu: Fix s/they disables/they disable/ typo in srcu_read_unlock_fast()
  srcu: Fix SRCU read flavor macro comments
  rcuscale: Ditch rcu_scale_shutdown in favor of torture_shutdown_init()
  refscale: Ditch ref_scale_shutdown in favor of torture_shutdown_init()
  rcutorture: Fix numeric "test" comparison in srcu_lockdep.sh
  torture: Print informative message for test without recheck file
  torture: Make hangs more visible in torture.sh output
  kvm-check-branches.sh: Remove in favor of kvm-series.sh
  rcutorture: Add a textbook-style trivial preemptible RCU

12 files changed, 73 insertions, 110 deletions

diff --git a/tools/testing/selftests/rcutorture/bin/kvm-check-branches.sh b/tools/testing/selftests/rcutorture/bin/kvm-check-branches.sh
deleted file mode 100755
index ed0ec7f0927e..000000000000
--- a/tools/testing/selftests/rcutorture/bin/kvm-check-branches.sh
+++ /dev/null
@@ -1,102 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0+
-#
-# Run a group of kvm.sh tests on the specified commits.  This currently
-# unconditionally does three-minute runs on each scenario in CFLIST,
-# taking advantage of all available CPUs and trusting the "make" utility.
-# In the short term, adjustments can be made by editing this script and
-# CFLIST.  If some adjustments appear to have ongoing value, this script
-# might grow some command-line arguments.
-#
-# Usage: kvm-check-branches.sh commit1 commit2..commit3 commit4 ...
-#
-# This script considers its arguments one at a time.  If more elaborate
-# specification of commits is needed, please use "git rev-list" to
-# produce something that this simple script can understand.  The reason
-# for retaining the simplicity is that it allows the user to more easily
-# see which commit came from which branch.
-#
-# This script creates a yyyy.mm.dd-hh.mm.ss-group entry in the "res"
-# directory.  The calls to kvm.sh create the usual entries, but this script
-# moves them under the yyyy.mm.dd-hh.mm.ss-group entry, each in its own
-# directory numbered in run order, that is, "0001", "0002", and so on.
-# For successful runs, the large build artifacts are removed.  Doing this
-# reduces the disk space required by about two orders of magnitude for
-# successful runs.
-#
-# Copyright (C) Facebook, 2020
-#
-# Authors: Paul E. McKenney <paulmck@kernel.org>
-
-if ! git status > /dev/null 2>&1
-then
-	echo '!!!' This script needs to run in a git archive. 1>&2
-	echo '!!!' Giving up. 1>&2
-	exit 1
-fi
-
-# Remember where we started so that we can get back at the end.
-curcommit="`git status | head -1 | awk '{ print $NF }'`"
-
-nfail=0
-ntry=0
-resdir="tools/testing/selftests/rcutorture/res"
-ds="`date +%Y.%m.%d-%H.%M.%S`-group"
-if ! test -e $resdir
-then
-	mkdir $resdir || :
-fi
-mkdir $resdir/$ds
-echo Results directory: $resdir/$ds
-
-RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
-PATH=${RCUTORTURE}/bin:$PATH; export PATH
-. functions.sh
-echo Using all `identify_qemu_vcpus` CPUs.
-
-# Each pass through this loop does one command-line argument.
-for gitbr in $@
-do
-	echo ' --- git branch ' $gitbr
-
-	# Each pass through this loop tests one commit.
-	for i in `git rev-list "$gitbr"`
-	do
-		ntry=`expr $ntry + 1`
-		idir=`awk -v ntry="$ntry" 'END { printf "%04d", ntry; }' < /dev/null`
-		echo ' --- commit ' $i from branch $gitbr
-		date
-		mkdir $resdir/$ds/$idir
-		echo $gitbr > $resdir/$ds/$idir/gitbr
-		echo $i >> $resdir/$ds/$idir/gitbr
-
-		# Test the specified commit.
-		git checkout $i > $resdir/$ds/$idir/git-checkout.out 2>&1
-		echo git checkout return code: $? "(Commit $ntry: $i)"
-		kvm.sh --allcpus --duration 3 --trust-make --datestamp "$ds/$idir" > $resdir/$ds/$idir/kvm.sh.out 2>&1
-		ret=$?
-		echo kvm.sh return code $ret for commit $i from branch $gitbr
-		echo Run results: $resdir/$ds/$idir
-		if test "$ret" -ne 0
-		then
-			# Failure, so leave all evidence intact.
-			nfail=`expr $nfail + 1`
-		else
-			# Success, so remove large files to save about 1GB.
-			( cd $resdir/$ds/$idir/$rrd; rm -f */vmlinux */bzImage */System.map */Module.symvers )
-		fi
-	done
-done
-date
-
-# Go back to the original commit.
-git checkout "$curcommit"
-
-if test $nfail -ne 0
-then
-	echo '!!! ' $nfail failures in $ntry 'runs!!!'
-	exit 1
-else
-	echo No failures in $ntry runs.
-	exit 0
-fi
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
index de65d77b47ff..63bbbdd5f4ef 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
@@ -39,7 +39,12 @@ do
 		X*)
 			;;
 		*)
-			kvm-recheck-${TORTURE_SUITE}.sh $i
+			if test -f tools/testing/selftests/rcutorture/bin/kvm-recheck-${TORTURE_SUITE}.sh
+			then
+				kvm-recheck-${TORTURE_SUITE}.sh $i
+			else
+				echo No kvm-recheck-${TORTURE_SUITE}.sh, so no ${TORTURE_SUITE}-specific analysis.
+			fi
 		esac
 		if test -f "$i/qemu-retval" && test "`cat $i/qemu-retval`" -ne 0 && test "`cat $i/qemu-retval`" -ne 137
 		then
@@ -49,7 +54,7 @@ do
 		then
 			if test -f "$i/qemu-retval" && test "`cat $i/qemu-retval`" -eq 137
 			then
-				echo QEMU killed
+				echo "Summary: Potential hang (QEMU killed)"
 			fi
 			configcheck.sh $i/.config $i/ConfigFragment > $i/ConfigFragment.diags 2>&1
 			if grep -q '^CONFIG_KCSAN=y$' $i/ConfigFragment.input
diff --git a/tools/testing/selftests/rcutorture/bin/parse-console.sh b/tools/testing/selftests/rcutorture/bin/parse-console.sh
index 21e6ba3615f6..be1e943ca4d5 100755
--- a/tools/testing/selftests/rcutorture/bin/parse-console.sh
+++ b/tools/testing/selftests/rcutorture/bin/parse-console.sh
@@ -113,7 +113,6 @@ then
 		then
 			print_warning $title `cat $T.seq`
 		fi
-		exit 2
 	fi
 fi | tee -a $file.diags
 
diff --git a/tools/testing/selftests/rcutorture/bin/srcu_lockdep.sh b/tools/testing/selftests/rcutorture/bin/srcu_lockdep.sh
index 208be7d09a61..4e98c697def4 100755
--- a/tools/testing/selftests/rcutorture/bin/srcu_lockdep.sh
+++ b/tools/testing/selftests/rcutorture/bin/srcu_lockdep.sh
@@ -50,7 +50,7 @@ do
 		do
 			err=
 			val=$((d*1000+t*10+c))
-			tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 5s --configs "SRCU-P" --kconfig "CONFIG_FORCE_NEED_SRCU_NMI_SAFE=y" --bootargs "rcutorture.test_srcu_lockdep=$val rcutorture.reader_flavor=0x2" --trust-make --datestamp "$ds/$val" > "$T/kvm.sh.out" 2>&1
+			tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 5s --configs "SRCU-P" --kconfig "CONFIG_FORCE_NEED_SRCU_NMI_SAFE=y" --bootargs "rcutorture.test_srcu_lockdep=$val rcutorture.reader_flavor=0x4" --trust-make --datestamp "$ds/$val" > "$T/kvm.sh.out" 2>&1
 			ret=$?
 			mv "$T/kvm.sh.out" "$RCUTORTURE/res/$ds/$val"
 			if ! grep -q '^CONFIG_PROVE_LOCKING=y' .config
@@ -92,12 +92,12 @@ do
 		nerrs=$((nerrs+1))
 		err=1
 	fi
-	if test "$val" -eq 0xf && test "$ret" -eq 0
+	if test "$val" = 0xf && test "$ret" -eq 0
 	then
 		err=1
 		echo -n Unexpected success for > "$RCUTORTURE/res/$ds/$val/kvm.sh.err"
 	fi
-	if test "$val" -eq 0x1 && test "$ret" -ne 0
+	if test "$val" = 0x1 && test "$ret" -ne 0
 	then
 		err=1
 		echo -n Unexpected failure for > "$RCUTORTURE/res/$ds/$val/kvm.sh.err"
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/NOCB01 b/tools/testing/selftests/rcutorture/configs/rcu/NOCB01
new file mode 100644
index 000000000000..bbe6d28210ab
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/NOCB01
@@ -0,0 +1,21 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=8
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y
+#CHECK#CONFIG_PREEMPT_RCU=y
+CONFIG_HZ_PERIODIC=n
+CONFIG_NO_HZ_IDLE=y
+CONFIG_NO_HZ_FULL=n
+CONFIG_RCU_TRACE=y
+CONFIG_HOTPLUG_CPU=y
+CONFIG_RCU_FANOUT=3
+CONFIG_RCU_FANOUT_LEAF=2
+CONFIG_RCU_NOCB_CPU=y
+CONFIG_DEBUG_LOCK_ALLOC=n
+CONFIG_PROVE_LOCKING=n
+CONFIG_RCU_BOOST=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
+CONFIG_RCU_EXPERT=y
+CONFIG_RCU_EQS_DEBUG=y
+CONFIG_RCU_LAZY=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/NOCB01.boot b/tools/testing/selftests/rcutorture/configs/rcu/NOCB01.boot
new file mode 100644
index 000000000000..5130bc84c435
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/NOCB01.boot
@@ -0,0 +1,2 @@
+rcupdate.rcu_self_test=1
+rcu_nocbs=all
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/NOCB02 b/tools/testing/selftests/rcutorture/configs/rcu/NOCB02
new file mode 100644
index 000000000000..4c2b8cd6d8fd
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/NOCB02
@@ -0,0 +1,20 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=8
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y
+#CHECK#CONFIG_PREEMPT_RCU=y
+CONFIG_HZ_PERIODIC=n
+CONFIG_NO_HZ_IDLE=y
+CONFIG_NO_HZ_FULL=n
+CONFIG_RCU_TRACE=y
+CONFIG_HOTPLUG_CPU=y
+CONFIG_RCU_FANOUT=3
+CONFIG_RCU_FANOUT_LEAF=2
+CONFIG_RCU_NOCB_CPU=y
+CONFIG_DEBUG_LOCK_ALLOC=n
+CONFIG_PROVE_LOCKING=n
+CONFIG_RCU_BOOST=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
+CONFIG_RCU_EXPERT=y
+CONFIG_RCU_EQS_DEBUG=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/NOCB02.boot b/tools/testing/selftests/rcutorture/configs/rcu/NOCB02.boot
new file mode 100644
index 000000000000..c212ae299b0b
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/NOCB02.boot
@@ -0,0 +1,3 @@
+rcupdate.rcu_self_test=1
+rcu_nocbs=all
+rcu_nocb_poll
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL-PREEMPT b/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL-PREEMPT
new file mode 100644
index 000000000000..8230b14bfe68
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL-PREEMPT
@@ -0,0 +1,12 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=8
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y
+CONFIG_HZ_PERIODIC=n
+CONFIG_NO_HZ_IDLE=y
+CONFIG_NO_HZ_FULL=n
+CONFIG_DEBUG_LOCK_ALLOC=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
+CONFIG_RCU_EXPERT=y
+CONFIG_TRIVIAL_PREEMPT_RCU=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL-PREEMPT.boot b/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL-PREEMPT.boot
new file mode 100644
index 000000000000..299cd3a12df6
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL-PREEMPT.boot
@@ -0,0 +1,3 @@
+rcutorture.torture_type=trivial-preempt
+rcutorture.onoff_interval=0
+rcutorture.shuffle_interval=0
diff --git a/tools/testing/selftests/rcutorture/configs/rcuscale/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/rcuscale/ver_functions.sh
index 28070b43f017..b78ddc243d89 100644
--- a/tools/testing/selftests/rcutorture/configs/rcuscale/ver_functions.sh
+++ b/tools/testing/selftests/rcutorture/configs/rcuscale/ver_functions.sh
@@ -11,7 +11,7 @@
 #
 # Adds per-version torture-module parameters to kernels supporting them.
 per_version_boot_params () {
-	echo	rcuscale.shutdown=1 \
+	echo	rcuscale.shutdown_secs=$3 \
 		rcuscale.verbose=0 \
 		$1
 }
diff --git a/tools/testing/selftests/rcutorture/configs/refscale/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/refscale/ver_functions.sh
index 748465627601..219fac070af2 100644
--- a/tools/testing/selftests/rcutorture/configs/refscale/ver_functions.sh
+++ b/tools/testing/selftests/rcutorture/configs/refscale/ver_functions.sh
@@ -11,7 +11,7 @@
 #
 # Adds per-version torture-module parameters to kernels supporting them.
 per_version_boot_params () {
-	echo	refscale.shutdown=1 \
+	echo	refscale.shutdown_secs=$3 \
 		refscale.verbose=0 \
 		$1
 }