binfmt_misc trouble with kernel 2.6.7

Hi,

A few days ago I upgraded to fedora kernel 2.6.7-1.494.2.2. Before that, I had kernels in which binfmt_misc was compiled as a module. The wine init script modprobe'd the module and then registered /usr/bin/wine as a handler for windows executables. However, in the new 2.6.7 kernel, binfmt_misc is compiled into the kernel, so the modprobe in the wine init script fails. I can fix that, but main problem I am having is that now, the permissions on the /proc/sys/fs/binfmt_misc directory are 0555:

dr-xr-xr-x 2 root root 0 Aug 13 19:04 /proc/sys/fs/binfmt_misc

I cannot create a file called register under /proc/sys/fs/binfmt_misc.

I created a Fedora bugzilla entry for this but I was told that this is a problem in the kernel upstream. Is this indeed a known problem, and is there a fix?

Geoffrey Leach from the Fedora list provided a hint to the solution. There's no bug. I just have to add:

none /proc/sys/fs/binfmt_misc binfmt_misc defaults 0 0

to my /etc/fstab, and then the /proc/sys/fs/binfmt_misc directory becomes writable, with a register and a status file in it. Sorry to have bothered you all.

That is certainly a Fedora bug if they update a kernel package that requires userland configs to be updated and then don't update those configs. This seems to be a common pattern with Fedora, the kernel packages change way faster than the userland tools and they are fast and loose about not updating userland. To be perfectly honest I switched to Debian partially for this reason.

Do they really claim this is not a bug?

Lee

We've always not had an automount for that line. If there was an automount it would keep loading that module for every user and 99.99999% of the users don't care about or use binfmt_misc.

That's a decision that goes back to RH8 or so when binfmt_misc first acquired its own file system.

Alan

Its not a kernel problem but a configuration one. The Fedora Core setup relies on binfmt_misc being a module in order to automount the binfmt_misc file system.

You're right. It's not a kernel bug at all. Up until fedora kernel 2.6.6, binfmt_misc was compiled as a module, and was loaded only when the wine script was run. When they changed it to compiled-in in kernel 2.6.7, they should have provided a script as part of the upgrade process. I've suggested that via bugzilla. Don't know if they will implement it.