Martin Lau <kafai@xxxxxx> writes:
> On Fri, Oct 18, 2019 at 09:44:18PM +0200, Toke Høiland-Jørgensen wrote:
>> It seems I forgot to add handling of devmap_hash type maps to the device
>> unregister hook for devmaps. This omission causes devices to not be
>> properly released, which causes hangs.
>>
>> Fix this by adding the missing handler.
>>
>> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
>> Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
>> ---
>> v3:
>> - Use u32 for loop iterator variable
>> - Since we're holding the lock we can just iterate with hlist_for_each_entry_safe()
>> v2:
>> - Grab the update lock while walking the map and removing entries.
>>
>> kernel/bpf/devmap.c | 30 ++++++++++++++++++++++++++++++
>> 1 file changed, 30 insertions(+)
>>
>> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
>> index c0a48f336997..012dbfb0f54b 100644
>> --- a/kernel/bpf/devmap.c
>> +++ b/kernel/bpf/devmap.c
>> @@ -719,6 +719,31 @@ const struct bpf_map_ops dev_map_hash_ops = {
>> .map_check_btf = map_check_no_btf,
>> };
>>
>> +static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
>> + struct net_device *netdev)
>> +{
>> + unsigned long flags;
>> + u32 i;
>> +
>> + spin_lock_irqsave(&dtab->index_lock, flags);
>> + for (i = 0; i < dtab->n_buckets; i++) {
>> + struct bpf_dtab_netdev *dev;
>> + struct hlist_head *head;
>> + struct hlist_node *next;
>> +
>> + head = dev_map_index_hash(dtab, i);
>> +
>> + hlist_for_each_entry_safe(dev, next, head, index_hlist) {
>> + if (netdev != dev->dev)
>> + continue;
>> +
>> + hlist_del_rcu(&dev->index_hlist);
> There is another issue...
> "dtab->items--;"
Right, of course. Thanks for your diligence in spotting my silly
mistakes! Will send a v4 :)
-Toke
