Split the signal-handler's lastSlave out into a separate variable.

dev->u.lastSlave was not signal safe since it was accessed by the DIX and
during signal handling.
Replaced with:
'dev->last.slave' for the signal handler's lastSlave (used to generate
                  DeviceChangedEvents), .
'dev->u.lastSlave' for the DIX lastSlave (currently only used in
                   change_modmap)

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

Xi/exevents.c

@@ -1010,7 +1010,6 @@ ProcessOtherEvent(InternalEvent *ev, DeviceIntPtr device)
     if (device->isMaster || !device->u.master)
         CheckMotion(event, device);
 
-
     switch (event->type)
     {
         case ET_Motion:

dix/devices.c

@@ -433,6 +433,18 @@ DisableDevice(DeviceIntPtr dev, BOOL sendevent)
 
     (void)(*dev->deviceProc)(dev, DEVICE_OFF);
     dev->enabled = FALSE;
+
+    /* now that the device is disabled, we can reset the signal handler's
+     * last.slave */
+    OsBlockSignals();
+    for (other = inputInfo.devices; other; other = other->next)
+    {
+        if (other->last.slave == dev)
+            other->last.slave = NULL;
+    }
+    OsReleaseSignals();
+
+
     *prev = dev->next;
     dev->next = inputInfo.off_devices;
     inputInfo.off_devices = dev;
@@ -2367,6 +2379,7 @@ AllocDevicePair (ClientPtr client, char* name,
     pointer->spriteInfo->spriteOwner = TRUE;
 
     pointer->u.lastSlave = NULL;
+    pointer->last.slave = NULL;
     pointer->isMaster = master;
 
     keyboard = AddInputDevice(client, CoreKeyboardProc, TRUE);
@@ -2389,6 +2402,7 @@ AllocDevicePair (ClientPtr client, char* name,
     keyboard->spriteInfo->spriteOwner = FALSE;
 
     keyboard->u.lastSlave = NULL;
+    keyboard->last.slave = NULL;
     keyboard->isMaster = master;
 
 

dix/getevents.c

@@ -199,10 +199,10 @@ CreateClassesChangedEvent(EventList* event,
     dce->length = sizeof(DeviceChangedEvent);
     dce->type = ET_DeviceChanged;
     dce->time = ms;
-    if (master->u.lastSlave)
+    if (master->last.slave)
     {
         dce->flags |= DEVCHANGE_HAS_OLD_SLAVE;
-        dce->old_slaveid = master->u.lastSlave->id;
+        dce->old_slaveid = master->last.slave->id;
     }
     dce->flags |= DEVCHANGE_HAS_NEW_SLAVE;
     dce->new_slaveid = slave->id;
@@ -294,7 +294,7 @@ updateSlaveDeviceCoords(DeviceIntPtr master, DeviceIntPtr pDev)
      * slave-device. If the old slave had less axes than this one,
      * last.valuators is reset to 0.
      */
-    if ((lastSlave = master->u.lastSlave) && lastSlave->valuator) {
+    if ((lastSlave = master->last.slave) && lastSlave->valuator) {
         for (i = 2; i < pDev->valuator->numAxes; i++) {
             if (i >= lastSlave->valuator->numAxes)
                 pDev->last.valuators[i] = 0;
@@ -612,11 +612,11 @@ static EventListPtr
 updateFromMaster(EventListPtr events, DeviceIntPtr dev, int *num_events)
 {
     DeviceIntPtr master = dev->u.master;
-    if (master && master->u.lastSlave != dev)
+    if (master && master->last.slave != dev)
     {
         CreateClassesChangedEvent(events, master, dev);
         updateSlaveDeviceCoords(master, dev);
-        master->u.lastSlave = dev;
+        master->last.slave = dev;
         master->last.numValuators = dev->last.numValuators;
         (*num_events)++;
         events++;

include/inputstr.h

@@ -507,6 +507,7 @@ typedef struct _DeviceIntRec {
         int             valuators[MAX_VALUATORS];
         float           remainder[MAX_VALUATORS];
         int             numValuators;
+        DeviceIntPtr    slave;
     } last;
 
     /* Input device property handling. */

mi/mieq.c

@@ -370,8 +370,11 @@ mieqProcessDeviceEvent(DeviceIntPtr dev,
         {
             handler(DequeueScreen(dev)->myNum, event, dev);
             if (master)
+            {
+                master->u.lastSlave = dev;
                 handler(DequeueScreen(master)->myNum,
                         (InternalEvent*)masterEvents->event, master);
+            }
         } else
         {
             /* process slave first, then master */