Red Hat Bugzilla – Bug 232748
X crashes during logout on x86_64 system with i945 graphics and XD disabled
Last modified: 2008-05-21 10:41:57 EDT
Description of problem:
X crashes on logout/restart when running x86_64 arch, i945 graphics and XD bit
capability is disabled
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. System with x86_64 processor but "Execute Disable" feature is off in BIOS
(or no option to turn on in BIOS). System is a Toshiba Satellite A105-S4334
with Core 2 Duo T5500. XD feature is disabled and cannot be set in the BIOS.
2. RHEL 5 x86_64 Desktop installed
3. If system is booted with rhgb option then system will crash after rhgb exits
and gdm should be loading. If rhgb is removed from grub.conf then user can
login but CTRL+ALT+Backspace will result in a crash.
System crashes when X is unloaded.
System should not crash.
I am relatively certain I am running against the bug described at:
I am testing the 1 liner patch from:
and will report back on whether or not that fixed the issue once I get a custom
OK, I have recompiled 2.6.18-8.1.1.el5.x86_64 with the patch from:
and can confirm that it fixes the problem. I can now successfully boot with
rhgb and can exit/restart X without any crashes.
I also checked the vanilla 184.108.40.206 kernel and found that the one line patch has
been added to the official kernel.
It would be nice to see this in 5.1. I know that many laptops and desktops
still ship with XD disabled by default and the solution is by no means obvious.
Unfortunately, this slipped through the cracks and missed the 5.1 deadline, but I'm getting it posted for
review for 5.2 (shouldn't have a problem getting in).
During review, the question as to whether or not this is also a problem under a
xen kernel came up. I don't have any reproducing hardware of my own readily
available, so I was hoping perhaps you could verify whether or not this problem
also occurs if you're booted on a xen kernel. (Because xen is xen, we have to
patch yet another file to fix this if its a problem w/the xen kernel too).
I have not had to deal with this bug in a while because Toshiba finally
enabled an XD setting in the BIOS of the A105 and I've upgraded to a newer
Toshiba laptop which has XD and VT. However, I'd still recommend fixing this as
there are still machines out there w/o a BIOS option nor is it obvious that
turning on XD in the BIOS will resolve the issue.
I borrowed back the A105 system and disabled XD in the BIOS, I found that
while I could reproduce the problem with the original x86-64 kernel for RHEL5
and the latest kernel from yum, I could not reproduce the problem using the
original RHEL5 xen kernel or the latest xen kernel from yum. Note that I did
not test stability under Xen extensively though so I am not 100% sure it doesn't
have issues but I could CTRL+ALT+Backspace the X under the xen kernels and X
would restart unlike the non-xen kernels which would crash at that point.
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release. Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update
You can download this test kernel from http://people.redhat.com/dzickus/el5
this bug has been tagged for inclusion in the RHEl5.2 release notes. please post
the necessary content for it. thanks!
x86_64 systems with Intel graphics and XD (execute disable) protection disabled
no longer crash upon exiting an X session.
thanks Jarod, adding to RHEL5.2 release notes under "Resolved Issues":
(x86_64) Systems equipped with Intel graphics cards that have the XD (execute
disable) option disabled no longer crash upon exiting an X session.
please advise if any further revisions are required.
the RHEL5.2 release notes will be dropped to translation on April 15, 2008, at
which point no further additions or revisions will be entertained.
a mockup of the RHEL5.2 release notes can be viewed at the following link:
please use the aforementioned link to verify if your bugzilla is already in the
release notes (if it needs to be). each item in the release notes contains a
link to its original bug; as such, you can search through the release notes by
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.