Date: Thu, 30 Aug 2012 08:59:09 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-net@freebsd.org Cc: net@freebsd.org, Navdeep Parhar <np@freebsd.org>, Vijay Singh <vijju.singh@gmail.com> Subject: Re: witness warning in arp processing Message-ID: <201208300859.09759.jhb@freebsd.org> In-Reply-To: <503E7F69.9070108@FreeBSD.org> References: <CALCNsJR-Gp05T10Bdf51zK15OcOyf=7qWZXNLEw-T6nxLsVArw@mail.gmail.com> <503E7F69.9070108@FreeBSD.org>
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On Wednesday, August 29, 2012 4:45:29 pm Navdeep Parhar wrote:
> On 08/29/12 10:30, Vijay Singh wrote:
> > All, I am seeing this warning on my 8.2 based system.
> >
> > taskqueue_drain with the following non-sleepable locks held:
> > exclusive rw lle (lle) r = 0 (0xffffff0014dc9110) locked @ sys/netinet/in.c:1760
> > KDB: stack backtrace:
> > kdb_backtrace() at kdb_backtrace+0x3e
> > _witness_debugger() at _witness_debugger+0x24
> > witness_warn() at witness_warn+0x402
> > taskqueue_drain() at taskqueue_drain+0x36
> > cancel_delayed_work() at cancel_delayed_work+0x56
> > set_timeout() at set_timeout+0x18
> > netevent_callback() at netevent_callback+0x29
> > _handle_arp_update_event() at _handle_arp_update_event+0x31
> > in_arpinput() at in_arpinput+0xe92
> > arpintr() at arpintr+0x255
> > netisr_dispatch_src() at netisr_dispatch_src+0x14a
> > netisr_dispatch() at netisr_dispatch+0x20
> > ether_demux() at ether_demux+0x281
> > ether_input_internal() at ether_input_internal+0x60c
> > ether_nh_input() at ether_nh_input+0x1d
> > netisr_dispatch_src() at netisr_dispatch_src+0x14a
> > netisr_dispatch() at netisr_dispatch+0x20
> > ether_input() at ether_input+0xef
> > lem_rxeof() at lem_rxeof+0x6ee
> > lem_handle_rxtx() at lem_handle_rxtx+0x4f
> > taskqueue_run_locked() at taskqueue_run_locked+0x145
> > taskqueue_thread_loop() at taskqueue_thread_loop+0x73
> > fork_exit() at fork_exit+0x180
> > fork_trampoline() at fork_trampoline+0xe
> >
> > Is this a known issue? Has it been fixed?
>
> This is a bug in the OFED code. The event handler it registers for the
> ARP update is not supposed to do anything that could sleep..
You could try this:
Index: ofed/include/linux/workqueue.h
===================================================================
--- ofed/include/linux/workqueue.h (revision 239905)
+++ ofed/include/linux/workqueue.h (working copy)
@@ -184,9 +184,9 @@ cancel_delayed_work(struct delayed_work *work)
{
callout_stop(&work->timer);
- if (work->work.taskqueue &&
- taskqueue_cancel(work->work.taskqueue, &work->work.work_task, NULL))
- taskqueue_drain(work->work.taskqueue, &work->work.work_task);
+ if (work->work.taskqueue)
+ taskqueue_cancel(work->work.taskqueue, &work->work.work_task,
+ NULL);
return 0;
}
This changes the code to match the comment above cancel_delayed_work()
and should fix this warning:
/*
* This may leave work running on another CPU as it does on Linux.
*/
static inline int
cancel_delayed_work(struct delayed_work *work)
--
John Baldwin
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