Kernel panics in tcp_twclose
Palle Girgensohn
girgen at pingpong.net
Wed Sep 23 22:05:10 UTC 2015
Hi,
> 23 sep 2015 kl. 20:32 skrev Julien Charbon <jch at freebsd.org>:
>
>
> 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
>
Kernels and userland are updated to 10.2-p3 with the patch removing the suspicous KASSERT.
dtrace running continously redirecting to a log file.
now we're just waiting... :)
Palle
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