sleep bug in taskqueue(9)

[Hans Petter Selasky]

On Friday 12 November 2010 15:18:46 mdf at freebsd.org wrote:
> On Fri, Nov 12, 2010 at 12:56 AM, Hans Petter Selasky <hselasky at c2i.net> 
wrote:
> > On Thursday 29 April 2010 01:59:58 Matthew Fleming wrote:
> >> It looks to me like taskqueue_drain(taskqueue_thread, foo) will not
> >> correctly detect whether or not a task is currently running.  The check
> >> is against a field in the taskqueue struct, but for the taskqueue_thread
> >> queue with more than one thread, multiple threads can simultaneously be
> >> running a task, thus stomping over the tq_running field.
> >> 
> >> I have not seen any problem with the code as-is in actual use, so this
> >> is purely an inspection bug.
> >> 
> >> The following patch should fix the problem.  Because it changes the size
> >> of struct task I'm not sure if it would be suitable for MFC.
> > 
> > 1) The u_char is going to leave a hole in that structure on ARM platforms
> > for example.
> > 
> > 2) The existing taskqueue implementation also has a missing check for the
> > pending count wrapping to zero. I.E. it should stick at 0xFFFF and not
> > wrap to 0.
> 
> This commit mail is rather old, and this fix was incorrect, because
> the task cannot be referenced after it has been run.  Some task
> handlers will free the task as part of the handler.

Ok, maybe the e-mail got stuck somewhere. Have you fixed the above mentioned 
issues in a newer patch?

--HPS