Date: Thu, 24 Sep 2015 07:51:02 +0200 From: Palle Girgensohn <girgen@pingpong.net> To: Julien Charbon <jch@freebsd.org> Cc: George Neville-Neil <gnn@FreeBSD.org>, freebsd-net@freebsd.org Subject: Re: Kernel panics in tcp_twclose Message-ID: <4E148E2E-F8D2-41C2-B232-9FD1548AA20B@pingpong.net> In-Reply-To: <54767991-9D3B-4ECB-A07E-CFA21A54BBDD@pingpong.net> References: <26B0FF93-8AE3-4514-BDA1-B966230AAB65@FreeBSD.org> <55FC1809.3070903@freebsd.org> <20150918160605.GN67105@kib.kiev.ua> <55FFBE01.6060706@freebsd.org> <3721F099-F45D-4DCD-8AB3-84D1ABC44145@FreeBSD.org> <73856F2B-3E70-483C-9988-C84E798CEB44@FreeBSD.org> <44EBAC98-4761-4E47-8E47-5032430A1C8A@FreeBSD.org> <56019AF8.8000705@freebsd.org> <F9D29C16-502B-43A1-BE2C-D2AD30F0B9EF@FreeBSD.org> <5601CF2D.9030307@freebsd.org> <E09DF89D-AAC5-48FD-8B75-EEAB937A5C32@FreeBSD.org> <5602E90A.9050504@freebsd.org> <0931591A-23EC-40CB-A109-72E9308B1A2D@pingpong.net> <5602F044.5010606@freebsd.org> <54767991-9D3B-4ECB-A07E-CFA21A54BBDD@pingpong.net>
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> 24 sep 2015 kl. 00:05 skrev Palle Girgensohn <girgen@pingpong.net>:
>=20
> Hi,
>=20
>> 23 sep 2015 kl. 20:32 skrev Julien Charbon <jch@freebsd.org>:
>>=20
>>=20
>> Hi,
>>=20
>> On 23/09/15 20:26, Palle Girgensohn wrote:
>>>> 23 sep. 2015 kl. 20:01 skrev Julien Charbon <jch@freebsd.org>:
>>>> On 23/09/15 16:36, Palle Girgensohn wrote:
>>>>>> 22 sep 2015 kl. 23:59 skrev Julien Charbon <jch@freebsd.org>: On
>>>>>> 22/09/15 22:58, Palle Girgensohn wrote:
>>>>>>>> 22 sep 2015 kl. 20:16 skrev Julien Charbon <jch@freebsd.org>:=20=
>>>>>>>> On 22/09/15 18:49, Palle Girgensohn wrote:
>>>>>>>>>> 22 sep 2015 kl. 18:46 skrev Palle Girgensohn=20
>>>>>>>>>> <girgen@FreeBSD.org>:
>>>>>>>>>>> 21 sep 2015 kl. 15:53 skrev Palle Girgensohn=20
>>>>>>>>>>> <girgen@FreeBSD.org>:
>>>>>>>>>>>> 21 sep 2015 kl. 10:21 skrev Julien Charbon=20
>>>>>>>>>>>> <jch@FreeBSD.org>: On 18/09/15 18:06, Konstantin
>>>>>>>>>>>> Belousov wrote:
>>>>>>>>>>>>> On Fri, Sep 18, 2015 at 03:56:25PM +0200, Julien
>>>>>>>>>>>>> Charbon wrote:
>>>>>>>>>>>>>> [...]
>>>>>>>>>>>> - Second, if issue is still in stable/10, compile 10.2=20
>>>>>>>>>>>> kernel with these options:
>>>>>>>>>>>>=20
>>>>>>>>>>>> options DDB options DEADLKRES options=20
>>>>>>>>>>>> INVARIANTS options INVARIANT_SUPPORT options
>>>>>>>>>>>> WITNESS options WITNESS_SKIPSPIN
>>>>>>>>>>>>=20
>>>>>>>>>>>> To see where the original fault is coming from.
>>>>>>>>>>> [...]
>>>>>>>>>>>=20
>>>>>>>>>>> I'll try stable/10 now. Would you suggest a "clean"=20
>>>>>>>>>>> stable/10, or could 287621 and 287780 help?
>>>>>>>>>>>=20
>>>>>>>>>>> I'll add the debugging suggested options right away.
>>>>>>>>>>>=20
>>>>>>>>>>> Palle
>>>>>>>>>>=20
>>>>>>>>>> I have a new core dump from ^/stable/10 with:
>>>>>>>>>>=20
>>>>>>>>>> options DDB options DEADLKRES options
>>>>>>>>>> INVARIANTS options INVARIANT_SUPPORT options WITNESS
>>>>>>>>>> options WITNESS_SKIPSPIN
>>>>>>>>>=20
>>>>>>>>> # kgdb kernel /var/crash/vmcore.2 GNU gdb 6.1.1 [FreeBSD]=20
>>>>>>>>> Copyright 2004 Free Software Foundation, Inc. GDB is free=20
>>>>>>>>> software, covered by the GNU General Public License, and you
>>>>>>>>> are welcome to change it and/or distribute copies of it under
>>>>>>>>> certain conditions. Type "show copying" to see the
>>>>>>>>> conditions. There is absolutely no warranty for GDB. Type
>>>>>>>>> "show warranty" for details. This GDB was configured as
>>>>>>>>> "amd64-marcel-freebsd"...
>>>>>>>>>=20
>>>>>>>>> Unread portion of the kernel message buffer: panic:
>>>>>>>>> tcp_detach: INP_TIMEWAIT && INP_DROPPED && tp !=3D NULL cpuid =
=3D
>>>>>>>>> 16 KDB: stack backtrace: db_trace_self_wrapper() at=20
>>>>>>>>> db_trace_self_wrapper+0x2b/frame 0xfffffe183d9e97e0=20
>>>>>>>>> kdb_backtrace() at kdb_backtrace+0x39/frame
>>>>>>>>> 0xfffffe183d9e9890 vpanic() at vpanic+0x126/frame
>>>>>>>>> 0xfffffe183d9e98d0 kassert_panic() at
>>>>>>>>> kassert_panic+0x139/frame 0xfffffe183d9e9940
>>>>>>>>> tcp_usr_detach() at tcp_usr_detach+0xf9/frame
>>>>>>>>> 0xfffffe183d9e9970 sofree() at sofree+0x1f1/frame
>>>>>>>>> 0xfffffe183d9e99a0 soclose() at soclose+0x3a0/frame
>>>>>>>>> 0xfffffe183d9e99f0 _fdrop() at _fdrop+0x29/frame
>>>>>>>>> 0xfffffe183d9e9a10 closef() at closef+0x1e2/frame
>>>>>>>>> 0xfffffe183d9e9aa0 closefp() at closefp+0x9d/frame
>>>>>>>>> 0xfffffe183d9e9ae0 amd64_syscall() at=20
>>>>>>>>> amd64_syscall+0x25a/frame 0xfffffe183d9e9bf0 Xfast_syscall()
>>>>>>>>> at Xfast_syscall+0xfb/frame 0xfffffe183d9e9bf0 --- syscall
>>>>>>>>> (6, FreeBSD ELF64, sys_close), rip =3D 0x801c8d94a, rsp =3D=20
>>>>>>>>> 0x7ffff91c8668, rbp =3D 0x7ffff91c8680 --- KDB: enter: panic=20=
>>>>>>>>> Uptime: 18h57m59s Dumping 23085 out of 98263=20
>>>>>>>>> MB:..1%..11%..21%..31%..41%..51%..61%..71%..81%..91%
>>>>>>>>>=20
>>>>>>>>> Reading symbols from /boot/kernel/nullfs.ko.symbols...done.=20
>>>>>>>>> Loaded symbols for /boot/kernel/nullfs.ko.symbols Reading
>>>>>>>>> symbols from /boot/kernel/zfs.ko.symbols...done. Loaded
>>>>>>>>> symbols for /boot/kernel/zfs.ko.symbols Reading symbols from
>>>>>>>>> /boot/kernel/opensolaris.ko.symbols...done. Loaded symbols
>>>>>>>>> for /boot/kernel/opensolaris.ko.symbols Reading symbols from
>>>>>>>>> /boot/kernel/ng_bridge.ko.symbols...done. Loaded symbols for
>>>>>>>>> /boot/kernel/ng_bridge.ko.symbols Reading symbols from=20
>>>>>>>>> /boot/kernel/netgraph.ko.symbols...done. Loaded symbols for=20
>>>>>>>>> /boot/kernel/netgraph.ko.symbols Reading symbols from=20
>>>>>>>>> /boot/kernel/ng_eiface.ko.symbols...done. Loaded symbols for
>>>>>>>>> /boot/kernel/ng_eiface.ko.symbols Reading symbols from=20
>>>>>>>>> /boot/kernel/ng_ether.ko.symbols...done. Loaded symbols for=20
>>>>>>>>> /boot/kernel/ng_ether.ko.symbols Reading symbols from=20
>>>>>>>>> /boot/kernel/accf_data.ko.symbols...done. Loaded symbols for
>>>>>>>>> /boot/kernel/accf_data.ko.symbols Reading symbols from=20
>>>>>>>>> /boot/kernel/accf_http.ko.symbols...done. Loaded symbols for
>>>>>>>>> /boot/kernel/accf_http.ko.symbols Reading symbols from=20
>>>>>>>>> /boot/kernel/ums.ko.symbols...done. Loaded symbols for=20
>>>>>>>>> /boot/kernel/ums.ko.symbols Reading symbols from=20
>>>>>>>>> /boot/kernel/ng_socket.ko.symbols...done. Loaded symbols for
>>>>>>>>> /boot/kernel/ng_socket.ko.symbols Reading symbols from=20
>>>>>>>>> /boot/kernel/fdescfs.ko.symbols...done. Loaded symbols for=20
>>>>>>>>> /boot/kernel/fdescfs.ko.symbols #0 doadump (textdump=3D1) at=20=
>>>>>>>>> pcpu.h:219 219 __asm("movq %%gs:%1,%0" : "=3Dr" (td) =
(kgdb) bt
>>>>>>>>> #0 doadump (textdump=3D1) at pcpu.h:219 #1 0xffffffff8094b337
>>>>>>>>> in kern_reboot (howto=3D260) at
>>>>>>>>> /usr/src/sys/kern/kern_shutdown.c:451 #2 0xffffffff8094b845
>>>>>>>>> in vpanic (fmt=3D<value optimized out>, ap=3D<value optimized
>>>>>>>>> out>) at /usr/src/sys/kern/kern_shutdown.c:758 #3
>>>>>>>>> 0xffffffff8094b6d9 in kassert_panic (fmt=3D<value optimized
>>>>>>>>> out>) at /usr/src/sys/kern/kern_shutdown.c:646 #4
>>>>>>>>> 0xffffffff80b1ee59 in tcp_usr_detach (so=3D<value optimized
>>>>>>>>> out>) at /usr/src/sys/netinet/tcp_usrreq.c:202 #5
>>>>>>>>> 0xffffffff809cd291 in sofree (so=3D0xfffff801dd302000) at=20
>>>>>>>>> /usr/src/sys/kern/uipc_socket.c:747 #6 0xffffffff809cdb00 in
>>>>>>>>> soclose (so=3D<value optimized out>) at=20
>>>>>>>>> /usr/src/sys/kern/uipc_socket.c:849 #7 0xffffffff808fe659 in
>>>>>>>>> _fdrop (fp=3D0xfffff802a593db40, td=3D0x0) at file.h:343 #8=20
>>>>>>>>> 0xffffffff80901092 in closef (fp=3D0xfffff802a593db40,=20
>>>>>>>>> td=3D0xfffff80eebc894a0) at
>>>>>>>>> /usr/src/sys/kern/kern_descrip.c:2338 #9 0xffffffff808feb5d
>>>>>>>>> in closefp (fdp=3D0xfffff80b20cce000, fd=3D<value optimized =
out>,
>>>>>>>>> fp=3D0xfffff802a593db40, td=3D0xfffff80eebc894a0,
>>>>>>>>> holdleaders=3D<value optimized out>) at=20
>>>>>>>>> /usr/src/sys/kern/kern_descrip.c:1194 #10 0xffffffff80d7bc3a
>>>>>>>>> in amd64_syscall (td=3D0xfffff80eebc894a0, traced=3D0) at=20
>>>>>>>>> subr_syscall.c:134 #11 0xffffffff80d5f1db in Xfast_syscall ()
>>>>>>>>> at /usr/src/sys/amd64/amd64/exception.S:396 #12
>>>>>>>>> 0x0000000801c8d94a in ?? () Previous frame inner to this
>>>>>>>>> frame (corrupt stack?) Current language: auto; currently
>>>>>>>>> minimal
>>>>>>>>=20
>>>>>>>> Thanks for the information. As I suspected the initial error
>>>>>>>> was elsewhere than tcp_twclose(), never got this assertion
>>>>>>>> before:
>>>>>>>>=20
>>>>>>>> tcp_detach: INP_TIMEWAIT && INP_DROPPED && tp !=3D NULL
>>>>>>>>=20
>>>>>>>> from here:
>>>>>>>>=20
>>>>>>>> static void tcp_detach(struct socket *so, struct inpcb *inp) {
>>>>>>>> struct tcpcb *tp;
>>>>>>>>=20
>>>>>>>> INP_INFO_WLOCK_ASSERT(&V_tcbinfo); INP_WLOCK_ASSERT(inp);
>>>>>>>>=20
>>>>>>>> KASSERT(so->so_pcb =3D=3D inp, ("tcp_detach: so_pcb !=3D =
inp"));=20
>>>>>>>> KASSERT(inp->inp_socket =3D=3D so, ("tcp_detach: inp_socket !=3D
>>>>>>>> so"));
>>>>>>>>=20
>>>>>>>> tp =3D intotcpcb(inp);
>>>>>>>>=20
>>>>>>>> if (inp->inp_flags & INP_TIMEWAIT) { if (inp->inp_flags &=20
>>>>>>>> INP_DROPPED) { KASSERT(tp =3D=3D NULL, ("tcp_detach: =
INP_TIMEWAIT
>>>>>>>> && " "INP_DROPPED && tp !=3D NULL"));
>>>>>>>>=20
>>>>>>>> Let me check if I could find a path that could lead to this=20
>>>>>>>> unexpected case. Unexpected because: INP_DROPPED and=20
>>>>>>>> inp->inp_ppcb is set to NULL are set at same time here:
>>>>>>>>=20
>>>>>>>> void tcp_twclose(struct tcptw *tw, int reuse) { struct socket
>>>>>>>> *so; struct inpcb *inp;
>>>>>>>>=20
>>>>>>>> inp =3D tw->tw_inpcb; KASSERT((inp->inp_flags & INP_TIMEWAIT),=20=
>>>>>>>> ("tcp_twclose: !timewait")); KASSERT(intotw(inp) =3D=3D tw,=20
>>>>>>>> ("tcp_twclose: inp_ppcb !=3D tw"));=20
>>>>>>>> INP_INFO_WLOCK_ASSERT(&V_tcbinfo); /* in_pcbfree() */=20
>>>>>>>> INP_WLOCK_ASSERT(inp);
>>>>>>>>=20
>>>>>>>> tcp_tw_2msl_stop(tw, reuse); inp->inp_ppcb =3D NULL;=20
>>>>>>>> in_pcbdrop(inp); ...
>>>>>>>>=20
>>>>>>>> Interesting [...]
>>>>>=20
>>>>> Just a quick update. Julien is pursuing this off list with a core
>>>>> dump and we are now waiting for a new core dump with the first
>>>>> KASSERT removed. this is on a stable/10 kernel.
>>>>=20
>>>> By the way Palle could you also run below Dtrace script to see =
where
>>>> this tcp_close() in INP_TIMEWAIT comes from:
>>>>=20
>>>> $ cat tcp-close-tw.d
>>>> fbt::tcp_close:entry
>>>> /args[0]->t_inpcb->inp_flags & 0x01000000/
>>>> {
>>>> @s1[stack()] =3D count()
>>>> }
>>>>=20
>>>> tick-1sec {
>>>> printa(@s1);
>>>> }
>>>> $ sudo dtrace -s tcp-close-tw.d
>>>>=20
>>>> And share any backtraces reported in this dtrace script output.
>>>>=20
>>>> George, could you check if this dtrace script makes sense for you, =
and
>>>> if you have any improvements to add, I am quite a rookie in Dtrace =
scripts.
>>>=20
>>> Shall I let the dtrace script run continuously until the machine =
crashes? Or just run it once?
>>=20
>> Continuously until the machine crashes. You can report any =
backstrace
>> outputs like:
>>=20
>> kernel`tcp_usr_close+0x86
>> kernel`soclose+0xe4
>> kernel`_fdrop+0x29
>> kernel`closef+0x237
>> kernel`closefp+0x95
>> kernel`amd64_syscall+0x357
>> kernel`0xffffffff80c83c4b
>> 1
>>=20
>> before the machine crashes. But I expect the problematic case
>> detection with Dtrace to be quickly followed by the crash. Will see.
>>=20
>> --
>> Julien
>>=20
>=20
> Kernels and userland are updated to 10.2-p3 with the patch removing =
the suspicous KASSERT.=20
>=20
> dtrace running continously redirecting to a log file.
>=20
> now we're just waiting... :)
>=20
> Palle
Is the dtrace correct?
$ sort -u dtrace.out=20
0 59779 :tick-1sec=20
CPU ID FUNCTION:NAME
$ wc -l dtrace.out=20
56233 dtrace.out
All it does is write
0 59779 :tick-1sec=20
once a second.
Just checking... :)
Palle
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