Kernel panics in tcp_twclose

[Palle Girgensohn]

> 18 sep 2015 kl. 18:06 skrev Konstantin Belousov <kostikbel at gmail.com>:
> 
>> On Fri, Sep 18, 2015 at 03:56:25PM +0200, Julien Charbon wrote:
>> Hi Palle,
>> 
>>> On 18/09/15 11:12, Palle Girgensohn wrote:
>>> We see daily panics on our production systems (web server, apache
>>> running MPM event, openjdk8. Kernel with VIMAGE. Jails using netgraph
>>> interfaces [not epair]).
>>> 
>>> The problem started after the summer. Normal port upgrades seems to
>>> be the only difference. The problem occurs with 10.2-p2 kernel as
>>> well as 10.1-p4 and 10.1-p15.
>>> 
>>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=203175
>>> 
>>> Any ideas?
>> 
>> Thanks for you detailed report.  I am not aware of any tcp_twclose()
>> related issues (without VIMAGE) since FreeBSD 10.0 (does not mean there
>> are none).  Few interesting facts (at least for me):
>> 
>> - Your crash happens when unlocking a inp exclusive lock with INP_WUNLOCK()
>> 
>> - Something is already wrong before calling turnstile_broadcast() as it
>> is called with ts = NULL:
> In the kernel without witness this is a 99%-sure indication of attempt to
> unlock not owned lock.
> 
>> 
>> turnstile_broadcast (ts=0x0, queue=1) at
>> /usr/src/sys/kern/subr_turnstile.c:838
>> __rw_wunlock_hard () at /usr/src/sys/kern/kern_rwlock.c:988
>> tcp_twclose () at /usr/src/sys/netinet/tcp_timewait.c:540
>> tcp_tw_2msl_scan () at /usr/src/sys/netinet/tcp_timewait.c:748
>> tcp_slowtimo () at /usr/src/sys/netinet/tcp_timer.c:198
>> 
>> I won't go to far here as I am not expert enough in VIMAGE, but one
>> question anyway:
>> 
>> - Can you correlate this kernel panic to a particular event?  Like for
>> example a VIMAGE/VNET jail destruction.
>> 
>> I will test that on my side on a 10.2 machine.
>> 
>> --
>> Julien
>> 
> 
> 


Hi,

I just got a response from adrian@ where he seems to remember that it has all been fixed in head. 

I would really prefer not to run a head kernel in production unless I have to, so the question is if it is possible to pin down the specific fixes for this problem? Any suggestions?

Thanks for all the help so far!

Palle