DeviceIntRec changes cause segfaults

Peter Hutterer mailinglists at
Thu Nov 16 00:50:36 PST 2006

Hey guys,

I just found out the following:

Adding a field to the struct _DeviceIntRec in xserver/include/ 
inputstr.h will cause the sever to segfault upon initialisation of  
the keyboard.

typedef struct _DeviceIntRec {
     DeviceRec	public;
     DeviceIntPtr next;
     TimeStamp	grabTime;
     Bool	startup;		/* true if needs to be turned on at
				          server intialization time */
     DeviceProc	deviceProc;		/* proc(DevicePtr, DEVICE_xx). It is
					  used to initialize, turn on, or
					  turn off the device */
     Bool	inited;			/* TRUE if INIT returns Success */
     Bool        enabled;                /* TRUE if ON returns  
Success */
     Bool        coreEvents;             /* TRUE if device also sends  
core */
#ifdef MPX
     Bool        isMPDev;                /* TRUE if multipointer  
device */
     GrabPtr	grab;			/* the grabber - used by DIX */

MPX is defined. Putting the very same line in comments will not  
segfault the server and everything works well. isMPDev is never  
accessed anywhere.

The exact location of the segfault is InitKBD at kbd.c:437

map is invalid but also KeyClassRec* keyc looks very strange.

Moving the isMPDev field within the struct will also change when the  
segfault happens.

This should not happen. I recompiled both xserver and driver/xf86- 
input-keyboard multiple times from scratch using the autogen scripts.  
The same problem does not happen with the mouse driver.

Am I missing something here?


Multi-Pointer X Server

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