From: Alexander Duyck <alexander.h.duyck@redhat.com>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: Re: [net-next PATCH 0/6] ipv4/fib_trie: Cleanups to prepare for introduction of key vector
Date: Wed, 04 Mar 2015 10:22:44 -0800 [thread overview]
Message-ID: <54F74D74.1050002@redhat.com> (raw)
In-Reply-To: <20150304.125327.2002716390225095168.davem@davemloft.net>
On 03/04/2015 09:53 AM, David Miller wrote:
> From: Alexander Duyck <alexander.h.duyck@redhat.com>
> Date: Wed, 04 Mar 2015 06:51:27 -0800
>
>> If bits can be 32 then idx should be an unsigned long which is 64
>> bits.
> unsigned long is 32-bit on 32-bit platforms
Right, but if unsigned long is 32 bits then usually a pointer is as
well. As a result we wouldn't be able to access the upper bits of a
node with bits == 32 since the size of the tnode would be over 4 * 2^32.
The general idea is the vmalloc should fail when we attempt to allocate
a bits == 32 tnode on a system w/ only 32b longs. Then again I think we
will probably cause a memory corruption on a 32b system since we are
probably overflowing size_t on the allocation if bits ==32. I'll have
to take a look as I believe we are using the offsetof macro and I am not
sure how that handles a 64b address on a 32b system.
- Alex
prev parent reply other threads:[~2015-03-04 18:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-02 21:32 [net-next PATCH 0/6] ipv4/fib_trie: Cleanups to prepare for introduction of key vector Alexander Duyck
2015-03-02 21:32 ` [net-next PATCH 1/6] fib_trie: Only resize tnodes once instead of on each leaf removal in fib_table_flush Alexander Duyck
2015-03-02 21:32 ` [net-next PATCH 2/6] fib_trie: Fib walk rcu should take a tnode and key instead of a trie and a leaf Alexander Duyck
2015-03-02 21:32 ` [net-next PATCH 3/6] fib_trie: Fib find node should return parent Alexander Duyck
2015-03-02 21:32 ` [net-next PATCH 4/6] fib_trie: Update insert and delete to make use of tp from find_node Alexander Duyck
2015-03-02 21:32 ` [net-next PATCH 5/6] fib_trie: move leaf and tnode to occupy the same spot in the key vector Alexander Duyck
2015-03-02 21:32 ` [net-next PATCH 6/6] fib_trie: Make fib_table rcu safe Alexander Duyck
2015-03-04 5:16 ` [net-next PATCH 0/6] ipv4/fib_trie: Cleanups to prepare for introduction of key vector David Miller
2015-03-04 14:51 ` Alexander Duyck
2015-03-04 17:53 ` David Miller
2015-03-04 18:22 ` Alexander Duyck [this message]
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