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List:       linux-netdev
Subject:    Re: [PATCH] ipv4: Restore old dst_free() behavior.
From:       Eric Dumazet <eric.dumazet () gmail ! com>
Date:       2012-07-31 5:54:57
Message-ID: 1343714097.21269.38.camel () edumazet-glaptop
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On Mon, 2012-07-30 at 22:38 -0700, David Miller wrote:
> Eric, this is what I'd like to propose.
> 
> It seems the problem you were likely running into was simply
> the fact that we were not inserting an RCU grace period for
> the dst_free() that we do when purging a FIB nexthop.
> 
> So this reverts your change, and instead adds the necessary
> call_rcu_bh() wrapper around the dst_free() done in fib_semantics.c
> 
> That makes it so that we don't need all of that inc_not_zero stuff for
> sockets, and the special dst flag.  If we set the pointer to NULL,
> then do the dst_free() via RCU, we can test that refcount safely in
> dst_free() since it can only decrease at that point.
> 
> What do you think?  Does it pass your tests?
> 
> Thanks.

I'll test that ASAP, I was trying to understand why Linus tree gave me a
non workable machine ( a panic in igb driver ... NULL RIP) .

I dont understand how I did not have this bug with net tree.

Please give me a couple of hours, I need to break my fast ;)


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