netdev - Re: Multicast routing stops functioning after 4G multicast packets recived.

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Message-ID: <alpine.LFD.2.11.1401042143330.1598@ja.home.ssi.bg>
Date:	Sat, 4 Jan 2014 21:55:51 +0200 (EET)
From:	Julian Anastasov <ja@....bg>
To:	Bob Falken <NetFestivalHaveFun@....com>
cc:	netdev@...r.kernel.org
Subject: Re: Multicast routing stops functioning after 4G multicast packets
 recived.


	Hello,

On Thu, 19 Dec 2013, Bob Falken wrote:

> Hello, I have an issue after kernel 2.6.37 and above.
> If i roll back to kernel 2.6.36.4 everything is fine.
> if recive more than 4294967295 multicast packets, the kernel does not register the multicast packets. and multicast routing does not functioning.

...

> I think there might be a variable in the kernel that get overflown. though i cannot be sure as im not a programmer. 
> 
> Let me know if you need more debug information.
> 
> Please help.  

	As Hannes guessed, may be it is really the missing
flags = FIB_LOOKUP_NOREF in ipmr_fib_lookup() when calling
fib_rules_lookup(), we have an atomic_inc_not_zero() there that
can stop to work after 4G lookups when rule's refcnt reaches 0.
As result, fib_rules_lookup() can start to return -ESRCH.

Regards

--
Julian Anastasov <ja@....bg>