cvs commit: src/sys/dev/random randomdev.c

John Baldwin jhb at FreeBSD.org
Fri Apr 16 11:08:33 PDT 2004


On Thursday 15 April 2004 02:54 pm, Robert Watson wrote:
> On Thu, 15 Apr 2004, John Baldwin wrote:
> > On Thursday 15 April 2004 03:32 am, Mike Silbersack wrote:
> > > On Tue, 13 Apr 2004, John Baldwin wrote:
> > > > You should drop the lock before uiomove().  If the uio can possibly
> > > > reference user memory, then uiomove() will do a copyout() which can
> > > > fault and thus sleep if the page is in swap.
> > > >
> > > > --
> > > > John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
> > >
> > > I'm going to have a similar problem in sendfile when I try to
> > > de-giantify it, and I'm sure read / write will have issues as well...
> > > will WITNESS catch this potential problem?
> >
> > Not currently.  One could add a WITNESS_WARN() check to uiomove() fairly
> > easily though to force witness to catch this.
>
> We also need to generate sleep warnings it M_TRYWAIT is passed to the mbuf
> allocator, which I believe we currently don't do.  Also, did we ever
> re-add the sleep warning to the process tracing code?

To STOPEVENT()?  No..

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org


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