Re: [PATCH] Removed unneeded access().

[Josh Stone <jistone at redhat dot com>]

On 06/13/2012 11:39 PM, Pasi Savanainen wrote:
> Actually my real problem was not an error message but it hides the
> fact from me that that loaded module couldn't be unloaded by staprun
> anymore. I had to manually remove the module.

Ah, right, because after failing to open it normally, we call
remove_module, and that's what gives up with the zombie message.  I
think that a new access() check as I mentioned on /sys/kernel/debug/
could be done before the module is ever loaded, to squash this earlier.

> I'm running Ubuntu 11.10 and it mounts debugfs by default as 0700.

That's unfortunate, but I can kind of understand that paranoia.  We
should at least figure out and document a remount command for stap fans
to use, and then perhaps later we'll have to really do that extra work
to pass file descriptors around.  Ugh.

I'll file a few bugs, and try to add that access() check at least.


Josh