Date: Thu, 3 Jun 2010 09:29:20 +0300 From: Nikolay Denev <ndenev@gmail.com> To: pyunyh@gmail.com Cc: freebsd-stable@freebsd.org, John Baldwin <jhb@freebsd.org> Subject: Re: if_sge related panics Message-ID: <87BA8EDC-BE95-4C84-94CD-5CA12961708A@gmail.com> In-Reply-To: <20100524171210.GA1418@michelle.cdnetworks.com> References: <E7AF7DD3-FE50-42DD-8391-0F576708EAF7@gmail.com> <77DFF2E5-7A1E-4063-A852-2C7AD9BC3DD4@gmail.com> <201005240948.33555.jhb@freebsd.org> <20100524171210.GA1418@michelle.cdnetworks.com>
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On May 24, 2010, at 8:12 PM, Pyun YongHyeon wrote:
> On Mon, May 24, 2010 at 09:48:33AM -0400, John Baldwin wrote:
>> On Monday 24 May 2010 6:35:01 am Nikolay Denev wrote:
>>> On May 24, 2010, at 8:57 AM, Nikolay Denev wrote:
>>>=20
>>>> Hi,
>>>>=20
>>>> Recently I started to experience a if_sge(4) related panic.
>>>> It happens almost every time I try to download a torrent file for =
example.
>>>> Copying of large files over NFS seem not to trigger it, but I =
haven't tested extensively.
>>>>=20
>>>> Here is the panic message :
>>>>=20
>>>> Fatal trap 12: page fault while in kernel mode
>>>> cpuid =3D 0; apic id =3D 00
>>>> fault virtual address =3D 0x8
>>>> fault code =3D supervisor write data, page =
not present
>>>> instruction pointer =3D 0x20:0xffffffff80230413
>>>> stack pointer =3D =
0x28:0xffffff80001e9280
>>>> frame pointer =3D 0x28:0xffffff80001e9510
>>>> code segment =3D base 0x0, limit 0xfffff, =
type 0x1b
>>>> =3D DPL 0, pres 1, long =
1, def32 0, gran 1
>>>> processor eflags =3D interrupt enabled, resume, =
IOPL =3D 0
>>>> current process =3D 12 (irq19: sge0)
>>>> trap number =3D 12
>>>> panic: page fault
>>>> cpuid =3D 0
>>>> Uptime: 1d20h56m20s
>>>> Cannot dump. Device not defined or unavailable
>>>> Automatic reboot in 15 seconds - press a key on the console to =
abort
>>>> Sleeping thread (tid 100039, pid 12) owns a non-sleepable lock
>>>>=20
>>>> My swap is on a zvol, so I don't have dump. I'll try to attach a =
disk on the eSATA port and dump there if needed.
>>>=20
>>> Here is some info from the crashdump :
>>>=20
>>> (kgdb) #0 doadump () at pcpu.h:223
>>> #1 0xffffffff802fb149 in boot (howto=3D260)
>>> at /usr/src/sys/kern/kern_shutdown.c:416
>>> #2 0xffffffff802fb57c in panic (fmt=3D0xffffffff8055d564 "%s")
>>> at /usr/src/sys/kern/kern_shutdown.c:590
>>> #3 0xffffffff805055b8 in trap_fatal (frame=3D0xffffff000288a3e0, =
eva=3DVariable "eva" is not available.
>>> )
>>> at /usr/src/sys/amd64/amd64/trap.c:777
>>> #4 0xffffffff805059dc in trap_pfault (frame=3D0xffffff80001e91d0, =
usermode=3D0)
>>> at /usr/src/sys/amd64/amd64/trap.c:693
>>> #5 0xffffffff805061c5 in trap (frame=3D0xffffff80001e91d0)
>>> at /usr/src/sys/amd64/amd64/trap.c:451
>>> #6 0xffffffff804eb977 in calltrap ()
>>> at /usr/src/sys/amd64/amd64/exception.S:223
>>> #7 0xffffffff80230413 in sge_start_locked (ifp=3D0xffffff000270d800)
>>> at /usr/src/sys/dev/sge/if_sge.c:1591
>>=20
>> Try this. sge_encap() can sometimes return an error with m_head set =
to NULL:
>>=20
>=20
> Thanks John. Committed in r208512.
>=20
>> Index: if_sge.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- if_sge.c (revision 208375)
>> +++ if_sge.c (working copy)
>> @@ -1588,7 +1588,8 @@
>> if (m_head =3D=3D NULL)
>> break;
>> if (sge_encap(sc, &m_head)) {
>> - IFQ_DRV_PREPEND(&ifp->if_snd, m_head);
>> + if (m_head !=3D NULL)
>> + IFQ_DRV_PREPEND(&ifp->if_snd, m_head);
>> ifp->if_drv_flags |=3D IFF_DRV_OACTIVE;
>> break;
>> }
>>=20
>> --=20
>> John Baldwin
After the patch I experienced several network outages (ping reporting =
"no buffer space available")
that were resolved by ifconfig down/up of the sge(4) interface.
I can see that most of the other drivers that handle XXX_encap() =
returning m_head pointing NULL, break when this condition
is hit: i.e. :
Index: if_sge.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- if_sge.c (revision 208375)
+++ if_sge.c (working copy)
@@ -1588,7 +1588,8 @@
if (m_head =3D=3D NULL)
break;
if (sge_encap(sc, &m_head)) {
- IFQ_DRV_PREPEND(&ifp->if_snd, m_head);
+ if (m_head =3D=3D NULL)
+ break;
IFQ_DRV_PREPEND(&ifp->if_snd, m_head);
ifp->if_drv_flags |=3D IFF_DRV_OACTIVE;
break;
}
But here in sge(4) we always set IFF_DRV_OACTIVE.
Do you think this can be the source of the problem ?
Regards,
Niki=
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