Serge E. Hallyn wrote:
> Quoting Dan Smith (danms@xxxxxxxxxx):
>> Sockets that have been disconnected from their struct file have
>> a reference count one less than normal sockets (potentially zero if the
>> socket is only in the system because of an outstanding skb). Since the
>> objhash assumes a minimum reference count of 2, skb's in such a situation
>> will always be counted as a leak.
>>
>> This (probably contentious) patch adds a fixup function during the leak
>
> This is IMO the right place for it though. If we have to play
> games with refcounts to pacify leak detection, then all such
> games should be played together in ckpt_obj_contained.
>
> Acked-by: Serge Hallyn <serue@xxxxxxxxxx>
I concur, it's a leak-detection specific code.
Pulled for v18.
Oren.
>
>
>> detection phase to adjust SOCK_DEAD sockets' reference counts down by
>> one to match reality.
>>
>> Signed-off-by: Dan Smith <danms@xxxxxxxxxx>
>> ---
>> checkpoint/objhash.c | 24 ++++++++++++++++++++++++
>> 1 files changed, 24 insertions(+), 0 deletions(-)
>>
>> diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
>> index b85aa77..ee9dbfd 100644
>> --- a/checkpoint/objhash.c
>> +++ b/checkpoint/objhash.c
>> @@ -816,6 +816,26 @@ static void ckpt_obj_users_inc(struct ckpt_ctx *ctx, void *ptr, int increment)
>> */
>>
>> /**
>> + * obj_sock_adjust_users - remove implicit reference on DEAD sockets
>> + * @obj: CKPT_OBJ_SOCK object to adjust
>> + *
>> + * Sockets that have been disconnected from their struct file have
>> + * a reference count one less than normal sockets. The objhash's
>> + * assumption of such a reference is therefore incorrect, so we correct
>> + * it here.
>> + */
>> +static inline void obj_sock_adjust_users(struct ckpt_obj *obj)
>> +{
>> + struct sock *sk = (struct sock *)obj->ptr;
>> +
>> + if (sock_flag(sk, SOCK_DEAD)) {
>> + obj->users--;
>> + ckpt_debug("Adjusting SOCK %i count to %i\n",
>> + obj->objref, obj->users);
>> + }
>> +}
>> +
>> +/**
>> * ckpt_obj_contained - test if shared objects are contained in checkpoint
>> * @ctx: checkpoint context
>> *
>> @@ -838,6 +858,10 @@ int ckpt_obj_contained(struct ckpt_ctx *ctx)
>> hlist_for_each_entry(obj, node, &ctx->obj_hash->list, next) {
>> if (!obj->ops->ref_users)
>> continue;
>> +
>> + if (obj->ops->obj_type == CKPT_OBJ_SOCK)
>> + obj_sock_adjust_users(obj);
>> +
>> if (obj->ops->ref_users(obj->ptr) != obj->users) {
>> ckpt_debug("usage leak: %s\n", obj->ops->obj_name);
>> ckpt_write_err(ctx, "OP", "leak: usage (%d != %d (%s)",
>> --
>> 1.6.2.5
>>
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