rcutorture: Add --kill-previous option to terminate previous kvm.sh runs

When kvm.sh is killed, its child processes (make, gcc, qemu, etc.) may
continue running. This prevents new kvm.sh instances from starting even
though the parent is gone.

Add a --kill-previous option that uses fuser(1) to terminate all
processes holding the flock file before attempting to acquire it. This
provides a clean way to recover from stale/zombie kvm.sh runs which
sometimes may have lots of qemu and compiler processes still disturbing.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>

diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index d1fbd092e22a11cbb40451354c0a290554b5aee5..65b04b8327330a543c536e0fc4838b5cec736598 100755 (executable)
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -80,6 +80,7 @@ usage () {
        echo "       --kasan"
        echo "       --kconfig Kconfig-options"
        echo "       --kcsan"
+       echo "       --kill-previous"
        echo "       --kmake-arg kernel-make-arguments"
        echo "       --mac nn:nn:nn:nn:nn:nn"
        echo "       --memory megabytes|nnnG"
@@ -206,6 +207,9 @@ do
        --kcsan)
                TORTURE_KCONFIG_KCSAN_ARG="$debuginfo CONFIG_KCSAN=y CONFIG_KCSAN_STRICT=y CONFIG_KCSAN_REPORT_ONCE_IN_MS=100000 CONFIG_KCSAN_VERBOSE=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y"; export TORTURE_KCONFIG_KCSAN_ARG
                ;;
+       --kill-previous)
+               TORTURE_KILL_PREVIOUS=1
+               ;;
        --kmake-arg|--kmake-args)
                checkarg --kmake-arg "(kernel make arguments)" $# "$2" '.*' '^error$'
                TORTURE_KMAKE_ARG="`echo "$TORTURE_KMAKE_ARG $2" | sed -e 's/^ *//' -e 's/ *$//'`"
@@ -278,6 +282,25 @@ done
 # Prevent concurrent kvm.sh runs on the same source tree.  The flock
 # is automatically released when the script exits, even if killed.
 TORTURE_LOCK="$RCUTORTURE/.kvm.sh.lock"
+
+# Terminate any processes holding the lock file, if requested.
+if test -n "$TORTURE_KILL_PREVIOUS"
+then
+       if test -e "$TORTURE_LOCK"
+       then
+               echo "Killing processes holding $TORTURE_LOCK..."
+               if fuser -k "$TORTURE_LOCK" >/dev/null 2>&1
+               then
+                       sleep 2
+                       echo "Previous kvm.sh processes killed."
+               else
+                       echo "No processes were holding the lock."
+               fi
+       else
+               echo "No lock file exists, nothing to kill."
+       fi
+fi
+
 if test -z "$dryrun"
 then
        # Create a file descriptor and flock it, so that when kvm.sh (and its
@@ -287,7 +310,7 @@ then
        then
                echo "ERROR: Another kvm.sh instance is already running on this tree."
                echo "       Lock file: $TORTURE_LOCK"
-               echo "       To run kvm.sh, kill all existing kvm.sh runs first."
+               echo "       To run kvm.sh, kill all existing kvm.sh runs first (--kill-previous)."
                exit 1
        fi
 fi