Re: [PATCH] tipc: ensure skb->lock is initialised

[Chris Packham]

On 9/07/19 8:43 AM, Chris Packham wrote:
> On 8/07/19 8:18 PM, Eric Dumazet wrote:
>>
>>
>> On 7/8/19 12:53 AM, Chris Packham wrote:
>>> tipc_named_node_up() creates a skb list. It passes the list to
>>> tipc_node_xmit() which has some code paths that can call
>>> skb_queue_purge() which relies on the list->lock being initialised.
>>> Ensure tipc_named_node_up() uses skb_queue_head_init() so that the lock
>>> is explicitly initialised.
>>>
>>> Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
>>
>> I would rather change the faulty skb_queue_purge() to __skb_queue_purge()
>>
> 
> Makes sense. I'll look at that for v2.
> 

Actually maybe not. tipc_rcast_xmit(), tipc_node_xmit_skb(), 
tipc_send_group_msg(), __tipc_sendmsg(), __tipc_sendstream(), and 
tipc_sk_timeout() all use skb_queue_head_init(). So my original change 
brings tipc_named_node_up() into line with them.

I think it should be safe for tipc_node_xmit() to use 
__skb_queue_purge() since all the callers seem to have exclusive access 
to the list of skbs. It still seems that the callers should all use 
skb_queue_head_init() for consistency.