Red Hat Bugzilla – Bug 986542
Xephyr segfault on some systems
Last modified: 2013-07-29 11:23:20 EDT
Created attachment 776146 [details]
Patch to fix the segfault.
This is related to bug #976995 (closed). I prefer to open a new bug report for more clarity.
The command "Xephyr -ac -br :4" lead to a segfault:
(EE) 0: /usr/bin/Xephyr (OsSigHandler+0x29) [0x467a49]
(EE) 1: /lib64/libpthread.so.0 (__restore_rt+0x0) [0x37a8c0ef9f]
(EE) 2: /usr/bin/Xephyr (ephyrHostXVAdaptorGetVideoFormats+0xba) [0x47785a]
(EE) 3: /usr/bin/Xephyr (ephyrInitVideo+0x707) [0x476b37]
(EE) 4: /usr/bin/Xephyr (ephyrInitScreen+0xd8) [0x4722a8]
(EE) 5: /usr/bin/Xephyr (KdScreenInit+0x217) [0x48e2b7]
(EE) 6: /usr/bin/Xephyr (AddScreen+0x71) [0x42ff31]
(EE) 7: /usr/bin/Xephyr (KdInitOutput+0x289) [0x48e799]
(EE) 8: /usr/bin/Xephyr (main+0x1db) [0x41e80b]
(EE) 9: /lib64/libc.so.6 (__libc_start_main+0xf5) [0x37a8821b75]
(EE) 10: /usr/bin/Xephyr (_start+0x29) [0x41ed41]
(EE) 11: ? (?+0x29) [0x29]
(EE) Segmentation fault at address 0x18
Fatal server error:
(EE) Caught signal 11 (Segmentation fault). Server aborting
This bug happens on the main system (fresh FC19 install). I cannot reproduce it on vitual systems. It did not happened on FC17.
This is due to the function 'XGetVisualInfo' returning a NULL pointer.
Here a patch to fix it.
Hi, Alphonse Steiner, are you the author of the patch to fix the segfault ?
if yes , is patch posted to the xorg-devel mailing list, to be merged on git master ?
Yes I am. I have not posted this patch elsewhere than this bugzilla.
hi, sorry for late response ,
I talked about this patch on xorg devel Mailing list 
You may wrote there and try submit the patch, in proper way and sign off it ...
I'm trying to help you, and thinking about this bug you wrote:
> This is due to the function 'XGetVisualInfo' returning a NULL pointer.
if XGetVisualInfo return NULL something is bad configured in your system, I think, I can't reproduce this bug.
$ LIBGL_DEBUG=verbose glxinfo
what is the output ?
First of all, thank you very much for your consideration. I really do appreciate it.
After a reboot on a new kernel, with new drivers and a few more updates, the segfault does not appear anymore. I do not know what is 'the' update that has fixed it. Maybe the intel driver? Anyway, it is fixed now.