Re: Yet another pipe related oops.

[Al Viro]

On Wed, Mar 27, 2013 at 05:45:06PM +0000, Al Viro wrote:
> We shouldn't, at least not for something that has been successfully
> opened.  I've a patch series cleaning that up a bit in the local
> queue; will check for bitrot and throw into for-next.

Egads...  OK, that has gone more than slightly out of control - right now
vfs.git#for-next is at 106 commits, -3.6KLoC balance and *still* hadn't
reached the ->f_op part of that work ;-/  OTOH, procfs-related code got
a lot cleaner and we actually have a chance to make the guts of proc_dir_entry
private to fs/proc now...  I'll cull the outright bug fixes into for-linus
and push it your way...

The thing that really worries me is debugfs; that fscker sets whatever
file_operations it's got from the driver that registered a file there
and sticks that into ->i_fop.  When we try to open() that, we get
try_module_get() ->i_fop->owner; so far, so good, but what if the driver
has just been removed *and* file_operations instance we are looking at
has already been freed?

IOW, how do we deal with a race between attempt to open a debugfs file and
its removal on driver unload?  Greg?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/