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Bug 1811747 - Linux X11 App displaying to RHEL7.7 Xserver kills Xserver. Remote display works fine on RHEL8.1 and Fedora.
Summary: Linux X11 App displaying to RHEL7.7 Xserver kills Xserver. Remote display wor...
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libX11
Version: 7.8
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Adam Jackson
QA Contact: Desktop QE
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2020-03-09 16:57 UTC by Vincent S. Cojot
Modified: 2023-09-07 22:16 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2020-11-11 21:50:35 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description Vincent S. Cojot 2020-03-09 16:57:00 UTC 
What problem/issue/behavior are you having trouble with?  What do you expect to see?
I was recently rebuilding an src.rpm of x48.
The src.rpm (attached) builds well on RHEL7.7, RHEL8.1 and Fedora30.

-BUT- when any platform displays -to- a RHEL7.7 display, the X server crashes.
In more details:
- SSH to RHEL 7.7, display on RHEL7.7 or display locally on a RHEL7.7 machine/VM = X server dies.
- SSH to RHEL 7.7, display on RHEL8.1 (physical machine or VM) or Fedora30 (physical machine): App works as expected.
- SSH to RHEL 8.1, display on RHEL7.7: X server dies.

The crash on RHEL7.7 happens with : Xvnc, Xorg with Nvidia and Xorg with i915.

It is easy to reproduce:
$ vncserver :1
$ export DISPLAY=:1.0
$ x48 -connFont fixed &
(watch the Xserver die).

x48 is an HP 48 emulator (https://github.com/gwenhael-le-moine/x48 seems alive) but at any case, it shouldn't kill the X server.

Using gdb, I traced the crash to one of the sub-routines of XLoadQueryFont(). 

Where are you experiencing the behavior? What environment?
When displaying to RHEL7.7

When does the behavior occur? Frequency? Repeatedly? At certain times?
100% reproductible
Comment 2 Vincent S. Cojot 2020-03-09 16:57:45 UTC 
[raistlin@daltigoth ~/World/Vincent/Code/GIT/x48/src]$ gdb ./x48
GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-115.el7
[...]
Reading symbols from /export/home/raistlin/World/Vincent/Code/GIT/x48/src/x48...done.

(gdb) set args -connFont  fixed

(gdb) show args
Argument list to give program being debugged when it is started is "-connFont  fixed".

(gdb) run
Starting program: /export/home/raistlin/World/Vincent/Code/GIT/x48/src/./x48 -connFont  fixed
x48: using XShm extension.
XIO:  fatal IO error 104 (Connection reset by peer) on X server ":1.0"
      after 4667 requests (4479 known processed) with 0 events remaining.
[Inferior 1 (process 75504) exited with code 01]
Missing separate debuginfos, use: debuginfo-install libX11-1.6.7-2.el7.i686 libXau-1.0.8-2.1.el7.i686 libXcursor-1.1.15-1.el7.i686 libXext-1.3.3-3.el7.i686 libXfixes-5.0.3-1.el7.i686 libXrender-0.9.10-1.el7.i686 libxcb-1.13-1.el7.i686 ncurses-libs-5.9-14.20130511.el7_4.i686 readline-6.2-11.el7.i686
Comment 3 Vincent S. Cojot 2020-03-09 16:59:45 UTC 
In the /var/log/Xorg.0.log.old of the host (here a VM running rhel7.7), I get this:
[  6984.849] AUDIT: Mon Mar  9 11:37:34 2020: 4166: client 23 disconnected
[  7045.828] AUDIT: Mon Mar  9 11:38:34 2020: 4166: client 23 connected from local host ( uid=1502 gid=100 pid=23004 )
  Auth name: MIT-MAGIC-COOKIE-1 ID: 945
[  7045.973] (EE) 
[  7045.973] (EE) Backtrace:
[  7045.986] (EE) 0: /usr/bin/X (xorg_backtrace+0x55) [0x55e72f7f64f5]
[  7045.986] (EE) 1: /usr/bin/X (0x55e72f645000+0x1b5179) [0x55e72f7fa179]
[  7045.986] (EE) 2: /lib64/libpthread.so.0 (0x7fdb7cbae000+0xf630) [0x7fdb7cbbd630]
[  7045.986] (EE) 3: /usr/bin/X (miHandleValidateExposures+0x29) [0x55e72f7eecd9]
[  7045.986] (EE) 4: /usr/bin/X (0x55e72f645000+0xe6352) [0x55e72f72b352]
[  7045.986] (EE) 5: /usr/bin/X (0x55e72f645000+0xe75a8) [0x55e72f72c5a8]
[  7045.986] (EE) 6: /usr/bin/X (0x55e72f645000+0xe20a9) [0x55e72f7270a9]
[  7045.986] (EE) 7: /usr/bin/X (0x55e72f645000+0x80bc2) [0x55e72f6c5bc2]
[  7045.986] (EE) 8: /usr/bin/X (FreeResource+0xde) [0x55e72f6c679e]
[  7045.986] (EE) 9: /usr/bin/X (0x55e72f645000+0xe6ab1) [0x55e72f72bab1]
[  7045.987] (EE) 10: /usr/bin/X (0x55e72f645000+0xe723b) [0x55e72f72c23b]
[  7045.987] (EE) 11: /usr/bin/X (0x55e72f645000+0xe580b) [0x55e72f72a80b]
[  7045.987] (EE) 12: /usr/bin/X (ReparentWindow+0x217) [0x55e72f6d0257]
[  7045.987] (EE) 13: /usr/bin/X (0x55e72f645000+0x568bc) [0x55e72f69b8bc]
[  7045.987] (EE) 14: /usr/bin/X (0x55e72f645000+0x5c4db) [0x55e72f6a14db]
[  7045.987] (EE) 15: /usr/bin/X (0x55e72f645000+0x6052a) [0x55e72f6a552a]
[  7045.987] (EE) 16: /lib64/libc.so.6 (__libc_start_main+0xf5) [0x7fdb7c802545]
[  7045.987] (EE) 17: /usr/bin/X (0x55e72f645000+0x4a61e) [0x55e72f68f61e]
[  7045.987] (EE) 
[  7045.987] (EE) Segmentation fault at address 0xa0011
[  7045.987] (EE) 
Fatal server error:
[  7045.987] (EE) Caught signal 11 (Segmentation fault). Server aborting
[  7045.987] (EE) 
[  7045.987] (EE) 
Please consult the The X.Org Foundation support 
         at http://wiki.x.org
 for help.

This issue is also seen with Xorg running on physical boxes with RHEL7.7.
If displaying on RHEL8 or Fedora, the App comes up fine. This seems like a bug in libX11 or an issue in the app that isn't handled well by the libX11 in RHEL7.7 (not sure about that)
Comment 4 Vincent S. Cojot 2020-04-12 03:10:31 UTC 
Same issue with the RHEL7.8 Xserver: x48 display to RHEL7.8 Xserver kills the Xserver but the same RHEL7-compiled binary -exporting- display to RHEL8 or Fedora30 works fine.
Comment 6 Vincent S. Cojot 2020-10-27 19:40:22 UTC 
Is there a way to debug this or figure what's causing the crash by running such a simple X11 app? Any hints would be welcomed.
Comment 7 Chris Williams 2020-11-11 21:50:35 UTC 
Red Hat Enterprise Linux 7 shipped it's final minor release on September 29th, 2020. 7.9 was the last minor releases scheduled for RHEL 7.
From intial triage it does not appear the remaining Bugzillas meet the inclusion criteria for Maintenance Phase 2 and will now be closed. 

From the RHEL life cycle page:
https://access.redhat.com/support/policy/updates/errata#Maintenance_Support_2_Phase
"During Maintenance Support 2 Phase for Red Hat Enterprise Linux version 7,Red Hat defined Critical and Important impact Security Advisories (RHSAs) and selected (at Red Hat discretion) Urgent Priority Bug Fix Advisories (RHBAs) may be released as they become available."

If this BZ was closed in error and meets the above criteria please re-open it flag for 7.9.z, provide suitable business and technical justifications, and follow the process for Accelerated Fixes:
https://source.redhat.com/groups/public/pnt-cxno/pnt_customer_experience_and_operations_wiki/support_delivery_accelerated_fix_release_handbook  

Feature Requests can re-opened and moved to RHEL 8 if the desired functionality is not already present in the product. 

Please reach out to the applicable Product Experience Engineer[0] if you have any questions or concerns.  

[0] https://bugzilla.redhat.com/page.cgi?id=agile_component_mapping.html&product=Red+Hat+Enterprise+Linux+7
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