2.6.9-bs7 panic on check_sysemu
I get this error starting up a 2.6.9-bs7 guest:
Checking syscall emulation patch for ptrace...<0>Kernel panic - not syncing: check_sysemu : expected SIGTRAP, got status = 256
The host is 2.6.8.1 with host-skas3-2.6.7-v2.patch.
The 2.6.9-bs7 kernel runs OK on my newer host kernels.
Is this a case where I should be upgrading my host kernels (will do that in time anyway)?
Or is there something that can be done on the guest to make it work on older kernels also?
Regards, Peter
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Quoted 11 lines · Peter
I get this error starting up a 2.6.9-bs7 guest:
Checking syscall emulation patch for ptrace...<0>Kernel panic - not
syncing:check_sysemu: expected SIGTRAP, got status = 256The host is 2.6.8.1 with host-skas3-2.6.7-v2.patch.
The 2.6.9-bs7 kernel runs OK on my newer host kernels.
Is this a case where I should be upgrading my host kernels (will do that in time anyway)?
You simply need to update the SKAS patch version. -V2 is very old, and many bugs (including this, that is a bug in the SYSEMU part of the SKAS patch). Upgrading to -V7 for the SKAS patch, even on the same host kernel version (i.e. against 2.6.8.1), would fix that.
Also, some older guest kernels may seem to work, because they don't diagnose such bugs. But actually they have problems in some situations, because of the host bugs. For instance panicking with a simple "echo 0 > /proc/sysemu; echo 1 > /proc/sysemu".
Quoted 3 lines
Or is there something that can be done on the guest to make it work on older kernels also?
Not a lot, except disabling SYSEMU (and its performance advantage) entirely - add the "nosysemu" param to the UML command line and it will work.
But it won't be as slow as if you didn't use SKAS.
Bye
Signature · 16 lines
Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ User-mode-linux-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
Quoted 16 lines · Blaisorblade
Quoted 2 lines
Is this a case where I should be upgrading my host kernels (will do that in time anyway)?
You simply need to update the SKAS patch version. -V2 is very old, and many bugs (including this, that is a bug in the SYSEMU part of the SKAS patch). Upgrading to -V7 for the SKAS patch, even on the same host kernel version (i.e. against 2.6.8.1), would fix that.
Also, some older guest kernels may seem to work, because they don't diagnose such bugs. But actually they have problems in some situations, because of the host bugs. For instance panicking with a simple "echo 0 >
/proc/sysemu; echo 1 >/proc/sysemu".Quoted 2 lines
Or is there something that can be done on the guest to make it work on older kernels also?
Quoted 6 lines
Not a lot, except disabling SYSEMU (and its performance advantage) entirely
- add the "nosysemu" param to the UML command line and it will work.But it won't be as slow as if you didn't use SKAS.
Bye
Speaking of which, I ask this from time to time:
What's the minimal patch set that _just_ adds -SKAS0 mode to something like a 2.6.11 kernel? I'd like to try it out, but every time I sit down to whack at it my interest budget runs out sifting through a mountain of unrelated x86-64 patches to try to figure out what exactly I need to apply to get just SKAS0...
No biggie. I'll can always ask again later... :)
Rob
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Quoted 27 lines · Rob Landley
Quoted 16 lines · Blaisorblade
Quoted 2 lines
Is this a case where I should be upgrading my host kernels (will do that in time anyway)?
You simply need to update the SKAS patch version. -V2 is very old, and many bugs (including this, that is a bug in the SYSEMU part of the SKAS patch). Upgrading to -V7 for the SKAS patch, even on the same host kernel version (i.e. against 2.6.8.1), would fix that.
Also, some older guest kernels may seem to work, because they don't diagnose such bugs. But actually they have problems in some situations, because of the host bugs. For instance panicking with a simple "echo 0 >
/proc/sysemu; echo 1 >/proc/sysemu".Quoted 2 lines
Or is there something that can be done on the guest to make it work on older kernels also?
Quoted 7 lines
Not a lot, except disabling SYSEMU (and its performance advantage) entirely - add the "nosysemu" param to the UML command line and it will work.
But it won't be as slow as if you didn't use SKAS.
Bye
Speaking of which, I ask this from time to time:
Quoted 7 lines
What's the minimal patch set that _just_ adds -SKAS0 mode to something like a 2.6.11 kernel? I'd like to try it out, but every time I sit down to whack at it my interest budget runs out sifting through a mountain of unrelated x86-64 patches to try to figure out what exactly I need to apply to get just SKAS0...
No biggie. I'll can always ask again later... :)
The problem is that I don't use the Jeff's tree nor work on SKAS0, since somebody must work on current releases.
While Jeff is loaded with development work and cannot handle every user. I too have sometimes problem to keep in touch with him.
That said, check if applying the whole tree (until the point patches apply) works for you.
Signature · 16 lines
Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ User-mode-linux-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
Quoted 25 lines · Rob Landley
Quoted 16 lines · Blaisorblade
Quoted 2 lines
Is this a case where I should be upgrading my host kernels (will do that in time anyway)?
You simply need to update the SKAS patch version. -V2 is very old, and many bugs (including this, that is a bug in the SYSEMU part of the SKAS patch). Upgrading to -V7 for the SKAS patch, even on the same host kernel version (i.e. against 2.6.8.1), would fix that.
Also, some older guest kernels may seem to work, because they don't diagnose such bugs. But actually they have problems in some situations, because of the host bugs. For instance panicking with a simple "echo 0 >
/proc/sysemu; echo 1 >/proc/sysemu".Quoted 2 lines
Or is there something that can be done on the guest to make it work on older kernels also?
Quoted 7 lines
Not a lot, except disabling SYSEMU (and its performance advantage) entirely - add the "nosysemu" param to the UML command line and it will work.
But it won't be as slow as if you didn't use SKAS.
Bye
Quoted 7 lines
Speaking of which, I ask this from time to time:
What's the minimal patch set that _just_ adds -SKAS0 mode to something like a 2.6.11 kernel? I'd like to try it out, but every time I sit down to whack at it my interest budget runs out sifting through a mountain of unrelated x86-64 patches to try to figure out what exactly I need to apply to get just SKAS0...
Also, I forgot: during your development work use SKAS. It doesn't give any big difference visible inside the Virtual Machine (except for bugs).
Signature · 16 lines
Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ User-mode-linux-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
Quoted 5 lines · Rob Landley
What's the minimal patch set that _just_ adds -SKAS0 mode to something like a 2.6.11 kernel? I'd like to try it out, but every time I sit down to whack at it my interest budget runs out sifting through a mountain of unrelated x86-64 patches to try to figure out what exactly I need to apply to get just SKAS0...
There isn't really one right now. Those patches need to be cleaned up, merged, and disentanged from other stuff.
Jeff
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Quoted 10 lines · Blaisorblade
Quoted 7 lines
Speaking of which, I ask this from time to time:
What's the minimal patch set that _just_ adds -SKAS0 mode to something like a 2.6.11 kernel? I'd like to try it out, but every time I sit down to whack at it my interest budget runs out sifting through a mountain of unrelated x86-64 patches to try to figure out what exactly I need to apply to get just SKAS0...
Also, I forgot: during your development work use SKAS. It doesn't give any big difference visible inside the Virtual Machine (except for bugs).
I'm trying out the build on various different systems: knoppix, red hat, suse, debian. In some cases running on borrowed machines, in other cases running on a knoppix boot cd. (I care because I'm using the host tools, which vary slightly from system to system.)
You just suggested that I replace the kernels on all of these systems, (including other people's machines, and the bootable CD that uses a kernel with the cloop patch applied and an initramfs that's hard to extract) with a different kernel. Just so I'm testing something faster that's not actually what I'm going to be deploying.
If I was going to replace the host kernel and run on a modified system, I'd just A) replace it with the version I actually need, B) run the build as root and use chroot instead of UML.
I'm interested in SKAS0 because it's potentially deployable. Any SKAS that requires a modified host kernel is not, for my purposes.
Rob
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