Re: rt remote free backtrace

["Sepherosa Ziehau" <sepherosa@xxxxxxxxx>]

On Mon, Oct 27, 2008 at 9:16 AM, Peter Avalos <pavalos@theshell.com> wrote:
> On Thu, Sep 11, 2008 at 07:36:02PM +0800, Sepherosa Ziehau wrote:
>> Hi all,
>>
>> I have committed a patch to HEAD, which will print backtrace if
>> rtfree_remote() is called.  If you see this kind of messages on your
>> console, please post them to bugs@.  If you think your box could
>> afford panicking (mainly to get coredumps), you could set
>> net.route.remote_free_panic to 1, and post the URL to the coredump so
>> we could fetch and debug it.
>>
>
> rt remote free rt_cpuid 1, mycpuid 0
> Trace beginning at frame 0xda6fbcd8
> rtfree_remote(c0371380,1,0,da6fbd00,c023d118) at rtfree_remote+0x74
> rtfree_remote(f5447ba0,0) at rtfree_remote+0x74
> in_pcbdetach(db085900) at in_pcbdetach+0x82
> in_pcbremwildcardhash_handler(f0bc3740,f0bc3740,0,da6fbd84,c024d097) at
> in_pcbremwildcardhash_handler+0x30
> netmsg_service(f0bc3740,1,0,c041d880,ff800000) at netmsg_service+0x44
> tcpmsg_service_loop(0,0,0,0,0) at tcpmsg_service_loop+0x40
> lwkt_exit() at lwkt_exit
>
> If this isn't known, let me know and I'll panic it next time it happens.

For a listen socket on tcp_input path, the listen socket's inp route
cache will be used to send RST, if it receives a TCP segment with
invalid flags combination.  This may lead to this route entry remote
free.

Please test/review following patch:
http://leaf.dragonflybsd.org/~sephe/tcp_respond.diff

Best Regards,
sephe

-- 
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