Merge tag 'rcu.release.v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

Pull RCU updates from Uladzislau Rezki:
 "Misc fixes:
   - check if IRQs are disabled in rcu_exp_need_qs()
   - instrument KCSAN exclusive-writer assertions
   - add extra WARN_ON_ONCE() check
   - set the cpu_no_qs.b.exp under lock
   - warn if callback enqueued on offline CPU

  Torture-test updates:
   - add rcutorture.preempt_duration kernel module parameter
   - make the TREE03 scenario do preemption
   - improve pooling timeouts for rcu_torture_writer()
   - improve output of "Failure/close-call rcutorture reader segments"
   - add some reader-state debugging checks
   - update doc of polled APIs
   - add extra diagnostics for per-reader-segment preemption
   - add an extra test for sched_clock()
   - improve testing on unresponsive systems

  SRCU updates:
   - improve doc for srcu_read_lock() in terms of return value
   - fix typo in comments
   - remove redundant GP sequence checks in the srcu_funnel_gp_start"

* tag 'rcu.release.v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (31 commits)
  srcu: Remove redundant GP sequence checks in srcu_funnel_gp_start
  srcu: Fix typo s/srcu_check_read_flavor()/__srcu_check_read_flavor()/
  srcu: Guarantee non-negative return value from srcu_read_lock()
  MAINTAINERS: Update RCU git tree
  rcu: Add lockdep_assert_irqs_disabled() to rcu_exp_need_qs()
  rcu: Add KCSAN exclusive-writer assertions for rdp->cpu_no_qs.b.exp
  rcu: Make preemptible rcu_exp_handler() check idempotency
  rcu: Replace open-coded rcu_exp_need_qs() from rcu_exp_handler() with call
  rcu: Move rcu_report_exp_rdp() setting of ->cpu_no_qs.b.exp under lock
  rcu: Make rcu_report_exp_cpu_mult() caller acquire lock
  rcu: Report callbacks enqueued on offline CPU blind spot
  rcutorture: Use symbols for SRCU reader flavors
  rcutorture: Add per-reader-segment preemption diagnostics
  rcutorture: Read CPU ID for decoration protected by both reader types
  rcutorture: Add preempt_count() to rcutorture_one_extend_check() diagnostics
  rcutorture: Add parameters to control polled/conditional wait interval
  rcutorture: Add documentation for recent conditional and polled APIs
  rcutorture: Ignore attempts to test preemption and forward progress
  rcutorture: Make rcutorture_one_extend() check reader state
  rcutorture: Pretty-print rcutorture reader segments
  ...

2 files changed, 22 insertions, 4 deletions

diff --git a/tools/testing/selftests/rcutorture/bin/kvm-remote.sh b/tools/testing/selftests/rcutorture/bin/kvm-remote.sh
index 134cdef5a6e0..48a8052d5dae 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-remote.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-remote.sh
@@ -181,10 +181,11 @@ done
 
 # Function to check for presence of a file on the specified system.
 # Complain if the system cannot be reached, and retry after a wait.
-# Currently just waits forever if a machine disappears.
+# Currently just waits 15 minutes if a machine disappears.
 #
 # Usage: checkremotefile system pathname
 checkremotefile () {
+	local nsshfails=0
 	local ret
 	local sleeptime=60
 
@@ -195,6 +196,11 @@ checkremotefile () {
 		if test "$ret" -eq 255
 		then
 			echo " ---" ssh failure to $1 checking for file $2, retry after $sleeptime seconds. `date` | tee -a "$oldrun/remote-log"
+			nsshfails=$((nsshfails+1))
+			if ((nsshfails > 15))
+			then
+				return 255
+			fi
 		elif test "$ret" -eq 0
 		then
 			return 0
@@ -268,12 +274,23 @@ echo All batches started. `date` | tee -a "$oldrun/remote-log"
 for i in $systems
 do
 	echo " ---" Waiting for $i `date` | tee -a "$oldrun/remote-log"
-	while checkremotefile "$i" "$resdir/$ds/remote.run"
+	while :
 	do
+		checkremotefile "$i" "$resdir/$ds/remote.run"
+		ret=$?
+		if test "$ret" -eq 1
+		then
+			echo " ---" Collecting results from $i `date` | tee -a "$oldrun/remote-log"
+			( cd "$oldrun"; ssh -o BatchMode=yes $i "cd $rundir; tar -czf - kvm-remote-*.sh.out */console.log */kvm-test-1-run*.sh.out */qemu[_-]pid */qemu-retval */qemu-affinity; rm -rf $T > /dev/null 2>&1" | tar -xzf - )
+			break;
+		fi
+		if test "$ret" -eq 255
+		then
+			echo System $i persistent ssh failure, lost results `date` | tee -a "$oldrun/remote-log"
+			break;
+		fi
 		sleep 30
 	done
-	echo " ---" Collecting results from $i `date` | tee -a "$oldrun/remote-log"
-	( cd "$oldrun"; ssh -o BatchMode=yes $i "cd $rundir; tar -czf - kvm-remote-*.sh.out */console.log */kvm-test-1-run*.sh.out */qemu[_-]pid */qemu-retval */qemu-affinity; rm -rf $T > /dev/null 2>&1" | tar -xzf - )
 done
 
 ( kvm-end-run-stats.sh "$oldrun" "$starttime"; echo $? > $T/exitcode ) | tee -a "$oldrun/remote-log"
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot b/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot
index 8e50bfd4b710..90318591dae2 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot
@@ -5,3 +5,4 @@ rcutree.gp_cleanup_delay=3
 rcutree.kthread_prio=2
 threadirqs
 rcutree.use_softirq=0
+rcutorture.preempt_duration=10