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authorAlfonso Sánchez-Beato <alfonso.sanchez-beato@canonical.com>2019-06-13 18:23:21 +0200
committerThomas Haller <thaller@redhat.com>2019-06-14 13:29:45 +0200
commita251712a729f676c9c2d38e469e4f88e250229ba (patch)
tree9ac0b393a6e6c988e816cea61eeee5364e9b1825
parent2653458a3ec17ae95acc13f203f92ba731f61387 (diff)
core/pppd-plugin: wait to recover port settings before notifying death
pppd restores the previous settings for the serial port it uses right before exiting. It is especially important to do so because otherwise ModemManager is not able to recover the port as it can receive a hangup event from the port due to CLOCAL not being restored. However, there is currently a race condition that produces this issue. This is because when PHASE_DEAD is notified, pppd still has not restored the port settings - it does that a bit later, in the die() function. This patch delays notifying PHASE_DEAD until when the exitnotify() hook is called by pppd: when this happens the port settings have already been restored. There were previously efforts to fix this in commit fe090c34b724, so PHASE_DEAD was used instead of PHASE_DISCONNECT to notify MM that the port was disconnected, but that still early to ensure that the port settings are restored. The MM traces seen when the bug is triggered are: ModemManager[2158]: <warn> (ttyACM1): could not re-acquire serial port lock: (5) Input/output error ModemManager[2158]: <warn> Couldn't load Operator Code: 'Cannot run sequence: 'Could not open serial device ttyACM1: it has been forced close' https://mail.gnome.org/archives/networkmanager-list/2019-June/msg00014.html
-rw-r--r--src/ppp/nm-pppd-plugin.c21
1 files changed, 18 insertions, 3 deletions
diff --git a/src/ppp/nm-pppd-plugin.c b/src/ppp/nm-pppd-plugin.c
index 626dcdbd8..f0b9027ca 100644
--- a/src/ppp/nm-pppd-plugin.c
+++ b/src/ppp/nm-pppd-plugin.c
@@ -51,7 +51,7 @@ static struct {
} gl;
static void
-nm_phasechange (void *data, int arg)
+nm_phasechange (int arg)
{
NMPPPStatus ppp_status = NM_PPP_STATUS_UNKNOWN;
char *ppp_phase;
@@ -168,6 +168,16 @@ nm_phasechange (void *data, int arg)
}
static void
+nm_phasechange_hook (void *data, int arg)
+{
+ /* We send the nofication in exitnotify instead */
+ if (arg == PHASE_DEAD)
+ return;
+
+ nm_phasechange (arg);
+}
+
+static void
nm_ip_up (void *data, int arg)
{
ipcp_options opts = ipcp_gotoptions[0];
@@ -181,7 +191,7 @@ nm_ip_up (void *data, int arg)
if (!opts.ouraddr) {
g_warning ("nm-ppp-plugin: didn't receive an internal IP from pppd!");
- nm_phasechange (NULL, PHASE_DEAD);
+ nm_phasechange (PHASE_DEAD);
return;
}
@@ -384,6 +394,11 @@ nm_exit_notify (void *data, int arg)
{
g_return_if_fail (G_IS_DBUS_CONNECTION (gl.dbus_connection));
+ /* We wait until this point to notify dead phase to make sure that
+ * the serial port has recovered already its original settings.
+ */
+ nm_phasechange (PHASE_DEAD);
+
g_message ("nm-ppp-plugin: cleaning up");
g_clear_object (&gl.dbus_connection);
@@ -435,7 +450,7 @@ plugin_init (void)
pap_passwd_hook = get_credentials;
pap_check_hook = get_pap_check;
- add_notifier (&phasechange, nm_phasechange, NULL);
+ add_notifier (&phasechange, nm_phasechange_hook, NULL);
add_notifier (&ip_up_notifier, nm_ip_up, NULL);
add_notifier (&exitnotify, nm_exit_notify, NULL);
add_ip6_notifier ();