Re: How to identify specific wait-state for a "DE" process?

[Paul Goyette <paul%vps1.whooppee.com@localhost>]

On Tue, 5 Jan 2016, Michael van Elst wrote:

> paul%vps1.whooppee.com@localhost (Paul Goyette) writes:
>
> > cv_wait() at cv_wait+0x116
> > fd_close() at fd_close+0x39a
> > fd_free() at fd_free+0x178
> > exit1() at exit1+0x10a
> > sys_exit() at sys_exit+0x3a
> > syscall() at syscall+0x9c
> > --- syscall (number 1) ---
>
> > So I guess I need to figure out which/what condvar it is waiting on...
>
>
> There is only one condvar that fd_close waits for:
>
>                /*
>                 * Wait for other references to drain.  This is typically
>                 * an application error - the descriptor is being closed
>                 * while still in use.
>                 * (Or just a threaded application trying to unblock its
>                 * thread that sleeps in (say) accept()).
>                 */
> ...
>                while ((ff->ff_refcnt & FR_MASK) != 0) {
>                        cv_wait(&ff->ff_closing, &fdp->fd_lock);
>                }

Yep, I found that chunk of code.  Perhaps filemon needs to run in a 
separate thread/lwp so that it can have a chance to close its access to 
the "borrowed" fd?

I need to figure out why this is a problem when filemon(4) "borrows" the 
fd for stdout, but is not a problem when it borrows a real file.



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