We run Midas with no problems on Rocky 9.4, although not in a virtual machine.  We're very close to the head of `develop`.

I'm fairly sure I've seen an error like this before.  I didn't pay it much attention because it was transitory and I was doing something weird at the time - probably 
stepping through with a debugger and hit a timeout.  It was definitely about an ODB semaphore but I can't recall if it was about a recursive call.

Basically I think Rocky 9.4 is a red herring.  Do you have another crashed copy of mserver/mhttpd running somewhere and stuck in limbo?  If it's a virtual machine 
are you sharing the shared memory location with the host, and running another midas on there?


> > We're trying to install the SuperCDMS version of MIDAS on a Rocky 9.4 Virtual 
> > Machine and are getting a persistent error when we run mserver.
> >
> > [mserver,ERROR] [odb.cxx:2498:db_lock_database,ERROR] cannot lock ODB semaphore, 
> > timeout 10000 ms, exiting...
> > db_lock_database: Detected recursive call to db_{lock,unlock}_database() while 
> > already inside db_{lock,unlock}_database(). Maybe this is a call from a signal 
> > handler. Cannot continue, aborting...
> > Aborted (core dumped)
> 
> This is super very bad. Since you have a core dump, please post the stack trace here (or email it to me).
> 
> I probably cannot debug your private version of midas and I will recommend that you install and run vanilla midas 
> mserver (just while we debug this problem).
> 
> Let's look at the core dump stack trace first, but likely we see a problem with System-V semaphores and hopefully it 
> is not some breakage due to Red Hat bogosity or due to something specific to running on a virtual machine.
> 
> If indeed this is Linux-kernel level breakage of System-V semaphores, solution would be to start using Posix 
> semaphores, something I wanted to do for a long time. We already switched MIDAS shared memory from System-V to Posix 
> shared memory.
> 
> If we are lucky it is just one more crasher bug in ODB. Let's see that core dump stack trace.
> 
> K.O.