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From:   paulmck@kernel.org
To:     rcu@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org,
        jiangshanlai@gmail.com, akpm@linux-foundation.org,
        mathieu.desnoyers@efficios.com, josh@joshtriplett.org,
        tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
        dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com,
        oleg@redhat.com, joel@joelfernandes.org,
        "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 15/28] torture: Prevent jitter processes from delaying failed run
Date:   Thu,  5 Nov 2020 15:47:06 -0800
Message-Id: <20201105234719.23307-15-paulmck@kernel.org>
In-Reply-To: <20201105234658.GA23142@paulmck-ThinkPad-P72>
References: <20201105234658.GA23142@paulmck-ThinkPad-P72>
Precedence: bulk

From: "Paul E. McKenney" <paulmck@kernel.org>

Even when the kernel panics and qemu dies, runs with jitter enabled will
continue uselessly until the jitter.sh processes terminate.  This can
be annoying if a planned one-hour run instead dies during boot.

This commit therefore kills the jitter.sh processes when the run ends
more than one minute prior to the termination time specified by the
kvm.sh --duration argument or its default.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh | 14 ++++++++++++++
 tools/testing/selftests/rcutorture/bin/kvm.sh            |  5 ++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
index d04966a..3cd03d0 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
@@ -226,6 +226,20 @@ do
 				echo "ps -fp $killpid" >> $resdir/Warnings 2>&1
 				ps -fp $killpid >> $resdir/Warnings 2>&1
 			fi
+			# Reduce probability of PID reuse by allowing a one-minute buffer
+			if test $((kruntime + 60)) -lt $seconds && test -s "$resdir/../jitter_pids"
+			then
+				awk < "$resdir/../jitter_pids" '
+				NF > 0 {
+					pidlist = pidlist " " $1;
+					n++;
+				}
+				END {
+					if (n > 0) {
+						print "kill " pidlist;
+					}
+				}' | sh
+			fi
 		else
 			echo ' ---' `date`: "Kernel done"
 		fi
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index 6eb1d3f..5ad3882 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -459,8 +459,11 @@ function dump(first, pastlast, batchnum)
 	print "if test -n \"$needqemurun\""
 	print "then"
 	print "\techo ---- Starting kernels. `date` | tee -a " rd "log";
-	for (j = 0; j < njitter; j++)
+	print "\techo > " rd "jitter_pids"
+	for (j = 0; j < njitter; j++) {
 		print "\tjitter.sh " j " " dur " " ja[2] " " ja[3] "&"
+		print "\techo $! >> " rd "jitter_pids"
+	}
 	print "\twait"
 	print "\techo ---- All kernel runs complete. `date` | tee -a " rd "log";
 	print "else"
-- 
2.9.5