Messages in this thread | | | Date | Mon, 1 Apr 2013 18:55:16 -0700 | From | Greg Kroah-Hartman <> | Subject | Re: Yet another pipe related oops. |
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On Tue, Apr 02, 2013 at 01:22:04AM +0100, Al Viro wrote: > On Tue, Apr 02, 2013 at 12:27:18AM +0100, Al Viro wrote: > > On Mon, Apr 01, 2013 at 02:44:36PM -0700, Greg Kroah-Hartman wrote: > > > > > I guess you are right, it will not. I guess we need to do what > > > > > character devices do and have an "intermediate" fops in order to protect > > > > > this. Would that work? > > > > > > > > You mean, with reassigning ->f_op in ->open()? That'll work, as long as > > > > we have exclusion between removal and fetching the sucker in primary > > > > ->open()... Where would you prefer to stash fops? > > > > > > Ick, that's not going to work as the current api just uses a fops and > > > debugfs doesn't keep anything else hanging around that referes to > > > something "before" that, like 'struct cdev' does. > > > > Er? How about just sticking it into dentry->d_fsdata and letting > > debugfs_remove() zero that out? What am I missing here?
Nothing, you are right, that would work just fine. Want me to fix it up, or do you want to?
> Hrm... For what it's worth, how do debugfs entries associated with > dynamic objects deal with debugfs_remove() vs. method calls? I don't > see _anything_ in {,__}debugfs_remove() that would looks like "wait > for ongoing write(2) attempts to complete". IOW, forget rmmod - WTF > protects us from access-after-free for any kind of data that isn't > permanently allocated?
Nothing protects you from that, that's what I was trying to get at with the dynamic attributes comment.
greg k-h
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