Merge tag 'rcu.6.4.april5.2023.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux

Pull RCU updates from Joel Fernandes:

 - Updates and additions to MAINTAINERS files, with Boqun being added to
   the RCU entry and Zqiang being added as an RCU reviewer.

   I have also transitioned from reviewer to maintainer; however, Paul
   will be taking over sending RCU pull-requests for the next merge
   window.

 - Resolution of hotplug warning in nohz code, achieved by fixing
   cpu_is_hotpluggable() through interaction with the nohz subsystem.

   Tick dependency modifications by Zqiang, focusing on fixing usage of
   the TICK_DEP_BIT_RCU_EXP bitmask.

 - Avoid needless calls to the rcu-lazy shrinker for CONFIG_RCU_LAZY=n
   kernels, fixed by Zqiang.

 - Improvements to rcu-tasks stall reporting by Neeraj.

 - Initial renaming of k[v]free_rcu() to k[v]free_rcu_mightsleep() for
   increased robustness, affecting several components like mac802154,
   drbd, vmw_vmci, tracing, and more.

   A report by Eric Dumazet showed that the API could be unknowingly
   used in an atomic context, so we'd rather make sure they know what
   they're asking for by being explicit:

      https://lore.kernel.org/all/20221202052847.2623997-1-edumazet@google.com/

 - Documentation updates, including corrections to spelling,
   clarifications in comments, and improvements to the srcu_size_state
   comments.

 - Better srcu_struct cache locality for readers, by adjusting the size
   of srcu_struct in support of SRCU usage by Christoph Hellwig.

 - Teach lockdep to detect deadlocks between srcu_read_lock() vs
   synchronize_srcu() contributed by Boqun.

   Previously lockdep could not detect such deadlocks, now it can.

 - Integration of rcutorture and rcu-related tools, targeted for v6.4
   from Boqun's tree, featuring new SRCU deadlock scenarios, test_nmis
   module parameter, and more

 - Miscellaneous changes, various code cleanups and comment improvements

* tag 'rcu.6.4.april5.2023.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux: (71 commits)
  checkpatch: Error out if deprecated RCU API used
  mac802154: Rename kfree_rcu() to kvfree_rcu_mightsleep()
  rcuscale: Rename kfree_rcu() to kfree_rcu_mightsleep()
  ext4/super: Rename kfree_rcu() to kfree_rcu_mightsleep()
  net/mlx5: Rename kfree_rcu() to kfree_rcu_mightsleep()
  net/sysctl: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  lib/test_vmalloc.c: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  tracing: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  misc: vmw_vmci: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  drbd: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access
  rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed
  rcu-tasks: Report stalls during synchronize_srcu() in rcu_tasks_postscan()
  rcu: Permit start_poll_synchronize_rcu_expedited() to be invoked early
  rcu: Remove never-set needwake assignment from rcu_report_qs_rdp()
  rcu: Register rcu-lazy shrinker only for CONFIG_RCU_LAZY=y kernels
  rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check
  rcu: Fix set/clear TICK_DEP_BIT_RCU_EXP bitmask race
  rcu/trace: use strscpy() to instead of strncpy()
  tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem
  ...

1 files changed, 78 insertions, 0 deletions

diff --git a/tools/testing/selftests/rcutorture/bin/srcu_lockdep.sh b/tools/testing/selftests/rcutorture/bin/srcu_lockdep.sh
new file mode 100755
index 000000000000..2e63ef009d59
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/bin/srcu_lockdep.sh
@@ -0,0 +1,78 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Run SRCU-lockdep tests and report any that fail to meet expectations.
+#
+# Copyright (C) 2021 Meta Platforms, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+usage () {
+	echo "Usage: $scriptname optional arguments:"
+	echo "       --datestamp string"
+	exit 1
+}
+
+ds=`date +%Y.%m.%d-%H.%M.%S`-srcu_lockdep
+scriptname="$0"
+
+T="`mktemp -d ${TMPDIR-/tmp}/srcu_lockdep.sh.XXXXXX`"
+trap 'rm -rf $T' 0
+
+RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
+PATH=${RCUTORTURE}/bin:$PATH; export PATH
+. functions.sh
+
+while test $# -gt 0
+do
+	case "$1" in
+	--datestamp)
+		checkarg --datestamp "(relative pathname)" "$#" "$2" '^[a-zA-Z0-9._/-]*$' '^--'
+		ds=$2
+		shift
+		;;
+	*)
+		echo Unknown argument $1
+		usage
+		;;
+	esac
+	shift
+done
+
+err=
+nerrs=0
+for d in 0 1
+do
+	for t in 0 1 2
+	do
+		for c in 1 2 3
+		do
+			err=
+			val=$((d*1000+t*10+c))
+			tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 5s --configs "SRCU-P" --bootargs "rcutorture.test_srcu_lockdep=$val" --trust-make --datestamp "$ds/$val" > "$T/kvm.sh.out" 2>&1
+			ret=$?
+			mv "$T/kvm.sh.out" "$RCUTORTURE/res/$ds/$val"
+			if test "$d" -ne 0 && test "$ret" -eq 0
+			then
+				err=1
+				echo -n Unexpected success for > "$RCUTORTURE/res/$ds/$val/kvm.sh.err"
+			fi
+			if test "$d" -eq 0 && test "$ret" -ne 0
+			then
+				err=1
+				echo -n Unexpected failure for > "$RCUTORTURE/res/$ds/$val/kvm.sh.err"
+			fi
+			if test -n "$err"
+			then
+				grep "rcu_torture_init_srcu_lockdep: test_srcu_lockdep = " "$RCUTORTURE/res/$ds/$val/SRCU-P/console.log" | sed -e 's/^.*rcu_torture_init_srcu_lockdep://' >> "$RCUTORTURE/res/$ds/$val/kvm.sh.err"
+				cat "$RCUTORTURE/res/$ds/$val/kvm.sh.err"
+				nerrs=$((nerrs+1))
+			fi
+		done
+	done
+done
+if test "$nerrs" -ne 0
+then
+	exit 1
+fi
+exit 0