3 files changed, 24 insertions, 2 deletions

diff --git a/src/login/logind-session.c b/src/login/logind-session.c
index eeb58c9031..477ac9ab1b 100644
--- a/src/login/logind-session.c
+++ b/src/login/logind-session.c
@@ -1053,6 +1053,27 @@ void session_restore_vt(Session *s) {
         s->vtfd = safe_close(s->vtfd);
 }
 
+void session_leave_vt(Session *s) {
+        assert(s);
+
+        /* This is called whenever we get a VT-switch signal from the kernel.
+         * We acknowledge all of them unconditionally. Note that session are
+         * free to overwrite those handlers and we only register them for
+         * sessions with controllers. Legacy sessions are not affected.
+         * However, if we switch from a non-legacy to a legacy session, we must
+         * make sure to pause all device before acknowledging the switch. We
+         * process the real switch only after we are notified via sysfs, so the
+         * legacy session might have already started using the devices. If we
+         * don't pause the devices before the switch, we might confuse the
+         * session we switch to. */
+
+        if (s->vtfd < 0)
+                return;
+
+        session_device_pause_all(s);
+        ioctl(s->vtfd, VT_RELDISP, 1);
+}
+
 bool session_is_controller(Session *s, const char *sender) {
         assert(s);
 
diff --git a/src/login/logind-session.h b/src/login/logind-session.h
index 9fb0188a84..a007fb5e84 100644
--- a/src/login/logind-session.h
+++ b/src/login/logind-session.h
@@ -174,6 +174,7 @@ KillWho kill_who_from_string(const char *s) _pure_;
 
 int session_prepare_vt(Session *s);
 void session_restore_vt(Session *s);
+void session_leave_vt(Session *s);
 
 bool session_is_controller(Session *s, const char *sender);
 int session_set_controller(Session *s, const char *sender, bool force);
diff --git a/src/login/logind.c b/src/login/logind.c
index f1b6a86298..8f00c46339 100644
--- a/src/login/logind.c
+++ b/src/login/logind.c
@@ -750,11 +750,11 @@ static int manager_vt_switch(sd_event_source *src, const struct signalfd_siginfo
         }
 
         if (active->vtfd >= 0) {
-                ioctl(active->vtfd, VT_RELDISP, 1);
+                session_leave_vt(active);
         } else {
                 LIST_FOREACH(sessions_by_seat, iter, m->seat0->sessions) {
                         if (iter->vtnr == active->vtnr && iter->vtfd >= 0) {
-                                ioctl(iter->vtfd, VT_RELDISP, 1);
+                                session_leave_vt(iter);
                                 break;
                         }
                 }