Re: [GIT]: Networking

Eric Dumazet
2009-08-05T07:20:54Z

Ingo Molnar a écrit :
> * Ingo Molnar <mingo@elte.hu> wrote:
>
>> FYI, -tip testing found that these bits trigger a missing lockdep
>> annotation warning:
>
> it's apparently using an zero-initialized spinlock. This is a
> side-effect of:
>
> dev_unicast_init(dev);
>
> in alloc_netdev_mq() making use of dev->addr_list_lock.
>
> Wouldnt the patch below be the right fix? The device has just been
> allocated freshly, it's not accessible anywhere yet so no locking is
> needed at all - in fact it's wrong to lock it here (the lock isnt
> initialized yet).
>
> This bug was apparently introduced via:
>
> | commit a6ac65db2329e7685299666f5f7b6093c7b0f3a0
> | Author: Jiri Pirko <jpirko@redhat.com>
> | Date: Thu Jul 30 01:06:12 2009 +0000
> |
> | net: restore the original spinlock to protect unicast list
>
> it needlessly added new locking and apparently nobody ran this patch
> with lockdep.
>
> Ingo
>
> Index: linux2/net/core/dev.c
> ===================================================================
> --- linux2.orig/net/core/dev.c
> +++ linux2/net/core/dev.c
> @@ -4007,9 +4007,7 @@ static void dev_unicast_flush(struct net
>
> static void dev_unicast_init(struct net_device *dev)
> {
> - netif_addr_lock_bh(dev);
> __hw_addr_init(&dev->uc);
> - netif_addr_unlock_bh(dev);
> }
>
>

Indeed, this function is static and thus only called from alloc_netdev_mq()