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ghaverla

Member

From: Dawson Creek, BC, Canada

Registered: 2017-06-19

Posts: 111  

vsyscall, 5.2.0-2 kernel and new libc?

I had a desktop machine lock up on me, and trying to get it regoing has been problematic.

Most of my computers are set with vsyscall=emulate on the command line, and as near as I can tell the only reason to have that setting, is that some sources of BOINC jobs require it.  At one time (2 years ago), there was a special setting for BOINC having to do with LIBC215.  I just went looking at Einstein @ Home, and no option like that appears to be present now.

In order to boot consistently now, I have had to remove execute permissions on /etc/init.d/boinc-client.  If I boot to multiuser mode, and check the kernel command line, I can see the vsyscall=emulate.  If I then restart BOINC, the system immediately locks up.

I had updated the system to the new libc (2.29-2) a few days ago.  It may be that it took BOINC a few days to "tickle" something, which is causing this crashing.

Is there any way to get more information as to what is happening?

ghaverla

Member

From: Dawson Creek, BC, Canada

Registered: 2017-06-19

Posts: 111  

Re: vsyscall, 5.2.0-2 kernel and new libc?

sysdig.com has an article on troubleshooting containers.  I believe this story has something to do with vsyscall later on in the document.

https://sysdig.com/blog/troubleshooting-containers/

But, an early troubleshooting step shown here, is to generate a core dump.

ulimit -c unlimited
bad_command_to_execute

For me, this is some kind of BOINC process.  It might be that executing the shell script in init.d might show something interesting, but I suppose the core produced would be of bash, dash or something like that.  So, I think I need to manually start a BOINC job, in the hopes that it makes this vsyscall?

ghaverla

Member

From: Dawson Creek, BC, Canada

Registered: 2017-06-19

Posts: 111  

Re: vsyscall, 5.2.0-2 kernel and new libc?

/proc/sys/debug/exception-trace has something to do with controlling verbosity (following that sysdig article).  It can hold a 0 (off) or 1 (on).  On my machine, it seems to be turned on already.