<div dir="ltr">I'm assuming FreeGrab explicitly does not allow NULLs because an unwanted instance of NULL would be quite the bug. </div><div class="gmail_extra"> <div class="gmail_quote">On Fri, Jul 12, 2013 at 8:28 AM, walter harms <<a href="mailto:wharms@bfs.de" target="_blank">wharms@bfs.de</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Am 11.07.2013 21:04, schrieb Peter Hutterer: <div><div class="h5">> If a client calls XIGrabDevice in response to a ButtonPress event (regular > event selection), the device will have a grab, but listener->grab is NULL. > > Check for that, to avoid logspam. > > [ 26293.863] (EE) BUG: triggered 'if (!pGrab)' > [ 26293.863] (EE) BUG: grabs.c:256 in FreeGrab() > [ 26293.863] (EE) > [ 26293.863] (EE) Backtrace: > [ 26293.864] (EE) 0: /usr/bin/Xorg (FreeGrab+0x54) [0x45d3fc] > [ 26293.864] (EE) 1: /usr/bin/Xorg (UpdateTouchesForGrab+0x135) [0x447d4e] > [ 26293.864] (EE) 2: /usr/bin/Xorg (ActivatePointerGrab+0x1ba) [0x447f3d] > [ 26293.864] (EE) 3: /usr/bin/Xorg (GrabDevice+0x3e6) [0x4503bc] > [ 26293.864] (EE) 4: /usr/bin/Xorg (ProcXIGrabDevice+0x1f9) [0x5981b1] > [ 26293.865] (EE) 5: /usr/bin/Xorg (ProcIDispatch+0x78) [0x58aa17] > [ 26293.865] (EE) 6: /usr/bin/Xorg (Dispatch+0x30d) [0x43347e] > [ 26293.865] (EE) 7: /usr/bin/Xorg (main+0x61d) [0x498175] > [ 26293.865] (EE) 8: /lib64/libc.so.6 (__libc_start_main+0xf5) [0x3df5621b75] > [ 26293.865] (EE) 9: /usr/bin/Xorg (_start+0x29) [0x423a19] > [ 26293.866] (EE) 10: ? (?+0x29) [0x29] > [ 26293.866] (EE) > > Signed-off-by: Peter Hutterer <<a href="mailto:peter.hutterer@who-t.net">peter.hutterer@who-t.net</a>> > --- > dix/events.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/dix/events.c b/dix/events.c > index 03b2d2e..ed3138d 100644 > --- a/dix/events.c > +++ b/dix/events.c > @@ -1441,7 +1441,8 @@ UpdateTouchesForGrab(DeviceIntPtr mouse) > listener->type = LISTENER_POINTER_GRAB; > else > listener->type = LISTENER_GRAB; > - FreeGrab(listener->grab); > + if (listener->grab) > + FreeGrab(listener->grab); > listener->grab = AllocGrab(grab); > } > } </div></div>free(NULL) works. IMHO this patch should go to FreeGrab() to be in line with other free() functions. Is there a special reason not to do this ? re wh <div class="HOEnZb"><div class="h5"> _______________________________________________ <a href="mailto:xorg-devel@lists.x.org">xorg-devel@lists.x.org</a>: X.Org development Archives: <a href="http://lists.x.org/archives/xorg-devel" target="_blank">http://lists.x.org/archives/xorg-devel</a> Info: <a href="http://lists.x.org/mailman/listinfo/xorg-devel" target="_blank">http://lists.x.org/mailman/listinfo/xorg-devel</a> </div></div></blockquote></div> -- Jasper </div>