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Date:      Mon, 8 Feb 2016 20:39:35 +0300
From:      Slawa Olhovchenkov <slw@zxy.spb.ru>
To:        Adrian Chadd <adrian.chadd@gmail.com>
Cc:        Luigi Rizzo <rizzo@iet.unipi.it>, "stable@freebsd.org" <stable@freebsd.org>
Subject:   Re: 82576 + NETMAP + VLAN
Message-ID:  <20160208173935.GK68298@zxy.spb.ru>
In-Reply-To: <CAJ-VmomzvoZZZPUveTZUJ5zAhHQkJ5M9%2B7gfN8gGSGp05JpOWw@mail.gmail.com>
References:  <CAJ-VmonO8ok=twgBGVMBiAs=AyRs4LUoDX6pGBtWStvndGKGzg@mail.gmail.com> <20151018210049.GT6469@zxy.spb.ru> <CAJ-Vmonfxz5vjVHqp6gS97mhnU10SLgohRA35O8MQLUzHvcsrw@mail.gmail.com> <20151022163519.GF6469@zxy.spb.ru> <CAJ-Vmok56uBJgJh4Bwr7yjNwsigU=ySBJ08H26caODAAxXNLRA@mail.gmail.com> <CA%2BhQ2%2Bg0ggpS%2BE5nOpON66efs7cwsed=NvaKa=mzsg6FycGhiQ@mail.gmail.com> <20160202204446.GQ88527@zxy.spb.ru> <20160204130029.GC88527@zxy.spb.ru> <CAJ-Vmok%2B7Vt4ww4iWkQY505eapxVQF4MBtnb%2BwGg-TNSmJTLGw@mail.gmail.com> <CAJ-VmomzvoZZZPUveTZUJ5zAhHQkJ5M9%2B7gfN8gGSGp05JpOWw@mail.gmail.com>

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On Thu, Feb 04, 2016 at 10:47:34AM -0800, Adrian Chadd wrote:

> .. but if it does, can you enable witness and see what it reports as
> lock order violations?

last STABLE:

1. first LOR (with poll, don't cause direct problems now):

lock order reversal:
 1st 0xfffff800946e6700 vm object (vm object) @ /usr/src/sys/vm/vm_fault.c:363
 2nd 0xffffffff813e14d8 netmap memory allocator lock (netmap memory allocator lock) @ /usr/src/sys/dev/netmap/netmap_mem2.c:393
KDB: stack backtrace:
#0 0xffffffff80970320 at kdb_backtrace+0x60
#1 0xffffffff809882ce at witness_checkorder+0xc7e
#2 0xffffffff8091fcbc at __mtx_lock_flags+0x4c
#3 0xffffffff806784f6 at netmap_mem_ofstophys+0x36
#4 0xffffffff80676834 at netmap_dev_pager_fault+0x34
#5 0xffffffff80b81a0f at dev_pager_getpages+0x3f
#6 0xffffffff80b8cc1e at vm_fault_hold+0x86e
#7 0xffffffff80b8c367 at vm_fault+0x77
#8 0xffffffff80d0e2c9 at trap_pfault+0x199
#9 0xffffffff80d0db47 at trap+0x527
#10 0xffffffff80cf4ce2 at calltrap+0x8

2. kqueue issuse (not LOR!)

acquiring duplicate lock of same type: "nm_kn_lock"
 1st nm_kn_lock @ /usr/src/sys/kern/kern_event.c:2003
 2nd nm_kn_lock @ /usr/src/sys/kern/kern_event.c:2003
KDB: stack backtrace:
#0 0xffffffff80970320 at kdb_backtrace+0x60
#1 0xffffffff809882ce at witness_checkorder+0xc7e
#2 0xffffffff8091fcbc at __mtx_lock_flags+0x4c
#3 0xffffffff808fd899 at knote+0x39
#4 0xffffffff8067636b at freebsd_selwakeup+0x8b
#5 0xffffffff80674eb5 at netmap_notify+0x55
#6 0xffffffff8067ccb6 at netmap_pipe_txsync+0x156
#7 0xffffffff80674740 at netmap_poll+0x400
#8 0xffffffff80676b8e at netmap_knrw+0x6e
#9 0xffffffff808fc57a at kqueue_register+0x64a
#10 0xffffffff808fcdd4 at kern_kevent_fp+0x144
#11 0xffffffff808fcc4f at kern_kevent+0x9f
#12 0xffffffff808fcaea at sys_kevent+0x12a
#13 0xffffffff80d0e914 at amd64_syscall+0x2d4
#14 0xffffffff80cf4fcb at Xfast_syscall+0xfb

Do you need anything?

> On 4 February 2016 at 10:47, Adrian Chadd <adrian.chadd@gmail.com> wrote:
> > I've no time to help with this, I'm sorry :(
> >
> >
> > -a
> >
> >
> > On 4 February 2016 at 05:00, Slawa Olhovchenkov <slw@zxy.spb.ru> wrote:
> >> On Tue, Feb 02, 2016 at 11:44:47PM +0300, Slawa Olhovchenkov wrote:
> >>
> >>> On Thu, Oct 22, 2015 at 11:24:53AM -0700, Luigi Rizzo wrote:
> >>>
> >>> > On Thu, Oct 22, 2015 at 11:12 AM, Adrian Chadd <adrian.chadd@gmail.com> wrote:
> >>> > > On 22 October 2015 at 09:35, Slawa Olhovchenkov <slw@zxy.spb.ru> wrote:
> >>> > >> On Sun, Oct 18, 2015 at 07:45:52PM -0700, Adrian Chadd wrote:
> >>> > >>
> >>> > >>> Heh, file a bug with luigi; it should be defined better inside netmap itself.
> >>> > >>
> >>> > >> I am CC: luigi.
> >>> > >>
> >>> > >> Next question: do kevent RX/TX sync?
> >>> > >> In my setup I am need to manual NIOCTXSYNC/NIOCRXSYNC.
> >>> > >
> >>> > > Hi,
> >>> > >
> >>> > > Nope. kqueue() doesn't do the implicit sync like poll() does; it's
> >>> > > just the notification path.
> >>> >
> >>> > actually not. When the file descriptor is registered there
> >>> > is an implicit sync, and there is another one when an event
> >>> > is posted for the file descriptor.
> >>> >
> >>> > unless there are bugs, of course.
> >>>
> >>> I found strange behaivor:
> >>>
> >>> 1. open netmap and register in main thread
> >>> 2. kevent register in different thread
> >>> 3. result: got event by kevent but no ring sinc (all head,tail,cur
> >>> still 0).
> >>>
> >>> Is this normal? Or is this bug?
> >>>
> >>> open and registering netmap in same thread as kevent resolve this.
> >>
> >> Also, kevent+netmap deadlocked for me:
> >>
> >>   PID    TID COMM             TDNAME           KSTACK
> >>  1095 100207 addos            -                mi_switch+0xe1 sleepq_catch_signals+0xab sleepq_timedwait_sig+0x10 _sleep+0x238 kern_nanosleep+0x10e sys_nanosleep+0x51 amd64_syscall+0x40f Xfast_syscall+0xfb
> >>  1095 100208 addos            worker#0         mi_switch+0xe1 sleepq_catch_signals+0xab sleepq_wait_sig+0xf _sleep+0x27d kern_kevent+0x401 sys_kevent+0x12a amd64_syscall+0x40f Xfast_syscall+0xfb
> >>  1095 100209 addos            worker#1         mi_switch+0xe1 turnstile_wait+0x42a __mtx_lock_sleep+0x26b knote+0x38 freebsd_selwakeup+0x8b netmap_notify+0x55 netmap_pipe_txsync+0x156 netmap_poll+0x400 netmap_knrw+0x6e kqueue_register+0x799 kern_kevent+0x158 sys_kevent+0x12a amd64_syscall+0x40f Xfast_syscall+0xfb
> >>  1095 100210 addos            worker#2         mi_switch+0xe1 sleepq_catch_signals+0xab sleepq_wait_sig+0xf _sleep+0x27d kern_kevent+0x401 sys_kevent+0x12a amd64_syscall+0x40f Xfast_syscall+0xfb
> >>  1095 100211 addos            worker#NOIP      mi_switch+0xe1 sleepq_catch_signals+0xab sleepq_wait_sig+0xf _sleep+0x27d kern_kevent+0x401 sys_kevent+0x12a amd64_syscall+0x40f Xfast_syscall+0xfb
> >>  1095 100212 addos            balancer         mi_switch+0xe1 turnstile_wait+0x42a __mtx_lock_sleep+0x26b knote+0x38 freebsd_selwakeup+0x8b netmap_notify+0x2a netmap_pipe_rxsync+0x54 netmap_poll+0x774 netmap_knrw+0x6e kern_kevent+0x5cc sys_kevent+0x12a amd64_syscall+0x40f Xfast_syscall+0xfb



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