Kernel panics in tcp_twclose
Julien Charbon
jch at freebsd.org
Wed Sep 23 18:32:54 UTC 2015
Hi,
On 23/09/15 20:26, Palle Girgensohn wrote:
>> 23 sep. 2015 kl. 20:01 skrev Julien Charbon <jch at freebsd.org>:
>> On 23/09/15 16:36, Palle Girgensohn wrote:
>>>> 22 sep 2015 kl. 23:59 skrev Julien Charbon <jch at freebsd.org>: On
>>>> 22/09/15 22:58, Palle Girgensohn wrote:
>>>>>> 22 sep 2015 kl. 20:16 skrev Julien Charbon <jch at freebsd.org>:
>>>>>> On 22/09/15 18:49, Palle Girgensohn wrote:
>>>>>>>> 22 sep 2015 kl. 18:46 skrev Palle Girgensohn
>>>>>>>> <girgen at FreeBSD.org>:
>>>>>>>>> 21 sep 2015 kl. 15:53 skrev Palle Girgensohn
>>>>>>>>> <girgen at FreeBSD.org>:
>>>>>>>>>> 21 sep 2015 kl. 10:21 skrev Julien Charbon
>>>>>>>>>> <jch at 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
>>>>>>>>>> kernel with these options:
>>>>>>>>>>
>>>>>>>>>> options DDB options DEADLKRES options
>>>>>>>>>> INVARIANTS options INVARIANT_SUPPORT options
>>>>>>>>>> WITNESS options WITNESS_SKIPSPIN
>>>>>>>>>>
>>>>>>>>>> To see where the original fault is coming from.
>>>>>>>>> [...]
>>>>>>>>>
>>>>>>>>> I'll try stable/10 now. Would you suggest a "clean"
>>>>>>>>> stable/10, or could 287621 and 287780 help?
>>>>>>>>>
>>>>>>>>> I'll add the debugging suggested options right away.
>>>>>>>>>
>>>>>>>>> Palle
>>>>>>>>
>>>>>>>> I have a new core dump from ^/stable/10 with:
>>>>>>>>
>>>>>>>> options DDB options DEADLKRES options
>>>>>>>> INVARIANTS options INVARIANT_SUPPORT options WITNESS
>>>>>>>> options WITNESS_SKIPSPIN
>>>>>>>
>>>>>>> # kgdb kernel /var/crash/vmcore.2 GNU gdb 6.1.1 [FreeBSD]
>>>>>>> Copyright 2004 Free Software Foundation, Inc. GDB is free
>>>>>>> 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"...
>>>>>>>
>>>>>>> Unread portion of the kernel message buffer: panic:
>>>>>>> tcp_detach: INP_TIMEWAIT && INP_DROPPED && tp != NULL cpuid =
>>>>>>> 16 KDB: stack backtrace: db_trace_self_wrapper() at
>>>>>>> db_trace_self_wrapper+0x2b/frame 0xfffffe183d9e97e0
>>>>>>> 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
>>>>>>> amd64_syscall+0x25a/frame 0xfffffe183d9e9bf0 Xfast_syscall()
>>>>>>> at Xfast_syscall+0xfb/frame 0xfffffe183d9e9bf0 --- syscall
>>>>>>> (6, FreeBSD ELF64, sys_close), rip = 0x801c8d94a, rsp =
>>>>>>> 0x7ffff91c8668, rbp = 0x7ffff91c8680 --- KDB: enter: panic
>>>>>>> Uptime: 18h57m59s Dumping 23085 out of 98263
>>>>>>> MB:..1%..11%..21%..31%..41%..51%..61%..71%..81%..91%
>>>>>>>
>>>>>>> Reading symbols from /boot/kernel/nullfs.ko.symbols...done.
>>>>>>> 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
>>>>>>> /boot/kernel/netgraph.ko.symbols...done. Loaded symbols for
>>>>>>> /boot/kernel/netgraph.ko.symbols Reading symbols from
>>>>>>> /boot/kernel/ng_eiface.ko.symbols...done. Loaded symbols for
>>>>>>> /boot/kernel/ng_eiface.ko.symbols Reading symbols from
>>>>>>> /boot/kernel/ng_ether.ko.symbols...done. Loaded symbols for
>>>>>>> /boot/kernel/ng_ether.ko.symbols Reading symbols from
>>>>>>> /boot/kernel/accf_data.ko.symbols...done. Loaded symbols for
>>>>>>> /boot/kernel/accf_data.ko.symbols Reading symbols from
>>>>>>> /boot/kernel/accf_http.ko.symbols...done. Loaded symbols for
>>>>>>> /boot/kernel/accf_http.ko.symbols Reading symbols from
>>>>>>> /boot/kernel/ums.ko.symbols...done. Loaded symbols for
>>>>>>> /boot/kernel/ums.ko.symbols Reading symbols from
>>>>>>> /boot/kernel/ng_socket.ko.symbols...done. Loaded symbols for
>>>>>>> /boot/kernel/ng_socket.ko.symbols Reading symbols from
>>>>>>> /boot/kernel/fdescfs.ko.symbols...done. Loaded symbols for
>>>>>>> /boot/kernel/fdescfs.ko.symbols #0 doadump (textdump=1) at
>>>>>>> pcpu.h:219 219 __asm("movq %%gs:%1,%0" : "=r" (td) (kgdb) bt
>>>>>>> #0 doadump (textdump=1) at pcpu.h:219 #1 0xffffffff8094b337
>>>>>>> in kern_reboot (howto=260) at
>>>>>>> /usr/src/sys/kern/kern_shutdown.c:451 #2 0xffffffff8094b845
>>>>>>> in vpanic (fmt=<value optimized out>, ap=<value optimized
>>>>>>> out>) at /usr/src/sys/kern/kern_shutdown.c:758 #3
>>>>>>> 0xffffffff8094b6d9 in kassert_panic (fmt=<value optimized
>>>>>>> out>) at /usr/src/sys/kern/kern_shutdown.c:646 #4
>>>>>>> 0xffffffff80b1ee59 in tcp_usr_detach (so=<value optimized
>>>>>>> out>) at /usr/src/sys/netinet/tcp_usrreq.c:202 #5
>>>>>>> 0xffffffff809cd291 in sofree (so=0xfffff801dd302000) at
>>>>>>> /usr/src/sys/kern/uipc_socket.c:747 #6 0xffffffff809cdb00 in
>>>>>>> soclose (so=<value optimized out>) at
>>>>>>> /usr/src/sys/kern/uipc_socket.c:849 #7 0xffffffff808fe659 in
>>>>>>> _fdrop (fp=0xfffff802a593db40, td=0x0) at file.h:343 #8
>>>>>>> 0xffffffff80901092 in closef (fp=0xfffff802a593db40,
>>>>>>> td=0xfffff80eebc894a0) at
>>>>>>> /usr/src/sys/kern/kern_descrip.c:2338 #9 0xffffffff808feb5d
>>>>>>> in closefp (fdp=0xfffff80b20cce000, fd=<value optimized out>,
>>>>>>> fp=0xfffff802a593db40, td=0xfffff80eebc894a0,
>>>>>>> holdleaders=<value optimized out>) at
>>>>>>> /usr/src/sys/kern/kern_descrip.c:1194 #10 0xffffffff80d7bc3a
>>>>>>> in amd64_syscall (td=0xfffff80eebc894a0, traced=0) at
>>>>>>> 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
>>>>>>
>>>>>> Thanks for the information. As I suspected the initial error
>>>>>> was elsewhere than tcp_twclose(), never got this assertion
>>>>>> before:
>>>>>>
>>>>>> tcp_detach: INP_TIMEWAIT && INP_DROPPED && tp != NULL
>>>>>>
>>>>>> from here:
>>>>>>
>>>>>> static void tcp_detach(struct socket *so, struct inpcb *inp) {
>>>>>> struct tcpcb *tp;
>>>>>>
>>>>>> INP_INFO_WLOCK_ASSERT(&V_tcbinfo); INP_WLOCK_ASSERT(inp);
>>>>>>
>>>>>> KASSERT(so->so_pcb == inp, ("tcp_detach: so_pcb != inp"));
>>>>>> KASSERT(inp->inp_socket == so, ("tcp_detach: inp_socket !=
>>>>>> so"));
>>>>>>
>>>>>> tp = intotcpcb(inp);
>>>>>>
>>>>>> if (inp->inp_flags & INP_TIMEWAIT) { if (inp->inp_flags &
>>>>>> INP_DROPPED) { KASSERT(tp == NULL, ("tcp_detach: INP_TIMEWAIT
>>>>>> && " "INP_DROPPED && tp != NULL"));
>>>>>>
>>>>>> Let me check if I could find a path that could lead to this
>>>>>> unexpected case. Unexpected because: INP_DROPPED and
>>>>>> inp->inp_ppcb is set to NULL are set at same time here:
>>>>>>
>>>>>> void tcp_twclose(struct tcptw *tw, int reuse) { struct socket
>>>>>> *so; struct inpcb *inp;
>>>>>>
>>>>>> inp = tw->tw_inpcb; KASSERT((inp->inp_flags & INP_TIMEWAIT),
>>>>>> ("tcp_twclose: !timewait")); KASSERT(intotw(inp) == tw,
>>>>>> ("tcp_twclose: inp_ppcb != tw"));
>>>>>> INP_INFO_WLOCK_ASSERT(&V_tcbinfo); /* in_pcbfree() */
>>>>>> INP_WLOCK_ASSERT(inp);
>>>>>>
>>>>>> tcp_tw_2msl_stop(tw, reuse); inp->inp_ppcb = NULL;
>>>>>> in_pcbdrop(inp); ...
>>>>>>
>>>>>> Interesting [...]
>>>
>>> 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.
>>
>> By the way Palle could you also run below Dtrace script to see where
>> this tcp_close() in INP_TIMEWAIT comes from:
>>
>> $ cat tcp-close-tw.d
>> fbt::tcp_close:entry
>> /args[0]->t_inpcb->inp_flags & 0x01000000/
>> {
>> @s1[stack()] = count()
>> }
>>
>> tick-1sec {
>> printa(@s1);
>> }
>> $ sudo dtrace -s tcp-close-tw.d
>>
>> And share any backtraces reported in this dtrace script output.
>>
>> 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.
>
> Shall I let the dtrace script run continuously until the machine crashes? Or just run it once?
Continuously until the machine crashes. You can report any backstrace
outputs like:
kernel`tcp_usr_close+0x86
kernel`soclose+0xe4
kernel`_fdrop+0x29
kernel`closef+0x237
kernel`closefp+0x95
kernel`amd64_syscall+0x357
kernel`0xffffffff80c83c4b
1
before the machine crashes. But I expect the problematic case
detection with Dtrace to be quickly followed by the crash. Will see.
--
Julien
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