Reproducable user mode system hang
I have seem to have found a method to hang the kernel from user mode. The system hangs and does not print an Oops. It still responds to network pings but nothing else.
I have successfully crashed the 2.6 kernels on three different machines (all athlon 2.6 kernels):
Linux rain.cs.man.ac.uk 2.6.5-1.358 #1 Sat May 8 09:04:50 EDT 2004 i686 athlon i386 GNU/Linux Linux solem.cs.man.ac.uk 2.6.6-1.374 #1 Wed May 19 12:44:14 EDT 2004 i686 athlon i386 GNU/Linux Linux hogshead 2.4.20-8 #1 Thu Mar 13 17:18:24 EST 2003 i686 athlon i386 GNU/Linux
This problem does not occur on any 2.4 kernel machines I have tried.
Reproducing the problem:
Unfortunately the problem occurs in the middle of a program execution and I have been unable to track it down.
Download kmd 0.9.19pre1 from (If anyone wants I could distribute my binarys):
http://www.cs.man.ac.uk/~brejc8/kmd/dist/KMD-0.9.19.pre1.tar.gz
In user mode configure, compile and execute from the source directory:
"./kmd -e ./jimulator"
In the memory windows in the address box type in "E1000000" and press return. This should now crash the system.
Kmd sporns an emulator (jimulator) with which it communicates using stdin/out pipes. I suspect it is a problem in the pipe communication. It occurs even when run under valgrind. I don't know of many methods of narrowing down the search.
Signature · 4 lines
Charlie Brej APT Group, Dept. Computer Science, University of Manchester Web: http://www.cs.man.ac.uk/~brejc8/ Tel: +44 161 275 6844 Mail: IT302, Manchester University, Manchester, M13 9PL, UK
Quoted 29 lines · Charlie Brej
I have seem to have found a method to hang the kernel from user mode. The system hangs and does not print an Oops. It still responds to network pings but nothing else.
I have successfully crashed the 2.6 kernels on three different machines (all athlon 2.6 kernels):
Linux rain.cs.man.ac.uk 2.6.5-1.358 #1 Sat May 8 09:04:50 EDT 2004 i686 athlon i386 GNU/Linux
Linux solem.cs.man.ac.uk 2.6.6-1.374 #1 Wed May 19 12:44:14 EDT 2004 i686 athlon i386 GNU/Linux
Linux hogshead 2.4.20-8 #1 Thu Mar 13 17:18:24 EST 2003 i686 athlon i386 GNU/LinuxThis problem does not occur on any 2.4 kernel machines I have tried.
Reproducing the problem:
Unfortunately the problem occurs in the middle of a program execution and I have been unable to track it down.
Download kmd 0.9.19pre1 from (If anyone wants I could distribute my binarys):
http://www.cs.man.ac.uk/~brejc8/kmd/dist/KMD-0.9.19.pre1.tar.gz
In user mode configure, compile and execute from the source directory:
"./kmd -e ./jimulator"
In the memory windows in the address box type in "E1000000" and press return.
This should now crash the system.
Quoted 4 lines
Kmd sporns an emulator (jimulator) with which it communicates using stdin/out pipes. I suspect it is a problem in the pipe communication. It occurs even when run under valgrind. I don't know of many methods of narrowing down the search.
Can you get any kind of trace (ctrl+sysrq+p or NMI oopser) ?
And also make sure to rerun the tests with newer v2.6's.
Quoted 1 line · Marcelo Tosatti
Can you get any kind of trace (ctrl+sysrq+p or NMI oopser) ?
I will be able to tell you tomorrow when I get back to work
Quoted 1 line
And also make sure to rerun the tests with newer v2.6's.
Well you are right. It seems to be either fixed in the newer kernel or not effecting the newer kernel. These two both worked fine with the redhat compiled 2.6.7:
Linux solem.cs.man.ac.uk 2.6.7-1.517 #1 Wed Aug 11 16:28:33 EDT 2004 i686 athlon i386 GNU/Linux Linux hilly.house 2.6.7-1.517 #1 Wed Aug 11 16:28:33 EDT 2004 i686 i686 i386 GNU/Linux
Did you have an idea of what was causing this?
Signature · 4 lines
Charlie Brej APT Group, Dept. Computer Science, University of Manchester Web: http://www.cs.man.ac.uk/~brejc8/ Tel: +44 161 275 6844 Mail: IT302, Manchester University, Manchester, M13 9PL, UK
Quoted 11 lines · Charlie Brej
Quoted 1 line · Marcelo Tosatti
Can you get any kind of trace (ctrl+sysrq+p or NMI oopser) ?
I will be able to tell you tomorrow when I get back to work
Quoted 1 line
And also make sure to rerun the tests with newer v2.6's.
Well you are right. It seems to be either fixed in the newer kernel or not effecting the newer kernel. These two both worked fine with the redhat compiled 2.6.7:
Quoted 6 lines
Linux solem.cs.man.ac.uk 2.6.7-1.517 #1 Wed Aug 11 16:28:33 EDT 2004 i686 athlon i386 GNU/Linux
Linux hilly.house 2.6.7-1.517 #1 Wed Aug 11 16:28:33 EDT 2004 i686 i686 i386 GNU/LinuxDid you have an idea of what was causing this?
Not a clue - but it seems to be fixed in recent kernels :)