Date: Fri, 12 Nov 2010 15:23:17 +0100 From: Hans Petter Selasky <hselasky@c2i.net> To: freebsd-current@freebsd.org Cc: mdf@freebsd.org Subject: Re: sleep bug in taskqueue(9) Message-ID: <201011121523.18044.hselasky@c2i.net> In-Reply-To: <AANLkTinVN=RsMQSvKCKmPg0M9vTZXk5mKmRSRR%2BVSzhh@mail.gmail.com> References: <06D5F9F6F655AD4C92E28B662F7F853E039E389A@seaxch09.desktop.isilon.com> <201011120956.04501.hselasky@c2i.net> <AANLkTinVN=RsMQSvKCKmPg0M9vTZXk5mKmRSRR%2BVSzhh@mail.gmail.com>
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On Friday 12 November 2010 15:18:46 mdf@freebsd.org wrote: > On Fri, Nov 12, 2010 at 12:56 AM, Hans Petter Selasky <hselasky@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
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