Bug 113892 - System freezes when strace attaches to XFree86
System freezes when strace attaches to XFree86
Status: CLOSED NOTABUG
Product: Fedora
Classification: Fedora
Component: XFree86 (Show other bugs)
1
i386 Linux
medium Severity medium
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Assigned To: Mike A. Harris
David Lawrence
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Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2004-01-19 17:44 EST by Lars Damerow
Modified: 2007-11-30 17:10 EST (History)
0 users

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Environment:
Last Closed: 2004-01-19 19:46:25 EST
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CRM:
Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---


Attachments (Terms of Use)
magic sysrq output of a machine in the frozen state (66.11 KB, text/plain)
2004-01-19 17:45 EST, Lars Damerow
no flags Details
magic sysrq task list output, round 2 (58.25 KB, text/plain)
2004-01-19 17:45 EST, Lars Damerow
no flags Details

  None (edit)
Description Lars Damerow 2004-01-19 17:44:06 EST
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4.1)
Gecko/20031114 Epiphany/1.0.4

Description of problem:
While trying to determine what XFree86 was doing, I ran 'strace -f -p
<pid>' on it. I got a few lines of unsurprising output and then the
machine froze up. I connected to the machine remotely and kill -9 X,
which returned the machine to a usable state.

I can reproduce this at will on several machines, and will include
magic-sysrq task list output from a machine in the frozen state.

Version-Release number of selected component (if applicable):
XFree86-4.3.0-42

How reproducible:
Always

Steps to Reproduce:
1. start X windows
2. run 'strace -f -p <pid>', where <pid> is the PID of the X binary
3. watch the machine freeze after spitting out some output.
4. if the machine doesn't freeze on its own, move the mouse.
    

Actual Results:  the machine is unresponsive, except for network
connections.

Expected Results:  strace should have shown process output until I hit
ctrl-c. the machine
shouldn't have frozen.

Additional info:
Comment 1 Lars Damerow 2004-01-19 17:45:03 EST
Created attachment 97111 [details]
magic sysrq output of a machine in the frozen state
Comment 2 Lars Damerow 2004-01-19 17:45:39 EST
Created attachment 97112 [details]
magic sysrq task list output, round 2
Comment 3 Mike A. Harris 2004-01-19 19:45:33 EST
When attempting to debug the X server, or any of its modules,
you must not run the debugging software from within the X server
you are attempting to debug/strace/etc.  You must run the X server
alone, and run the debugger/strace/etc. from a remote network
session or serial console, or other access mechanism.

Closing as NOTABUG.
Comment 4 Lars Damerow 2004-01-19 20:10:46 EST
gotcha. thanks!
-lars

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