Hi,
inline
----- Original Message -----
> From: "Swen Schillig" <s...@vnet.ibm.com>
> To: "Matt Benjamin" <mbenja...@redhat.com>, "Daniel Gryniewicz"
> <d...@redhat.com>
> Cc: "nfs-ganesha-devel" <nfs-ganesha-devel@lists.sourceforge.net>
> Sent: Tuesday, September 6, 2016 4:10:32 PM
> Subject: [ntirpc] refcount issue ?
>
> Matt, Dan.
>
> Could you please have a look at the following code areas and verify
> what I think is a refcount issue.
>
> clnt_vc_ncreate2()
> {
> ...
> if ((oflags & RPC_DPLX_LKP_OFLAG_ALLOC) || (!rec->hdl.xd)) {
> xd = rec->hdl.xd = alloc_x_vc_data();
> ...
> } else {
> xd = rec->hdl.xd;
> ++(xd->refcnt); <=== this is not right. we're not taking an
> addtl' ref
Aren't we? We now share a ref to previously allocated rec->hdl.xd.
> here.
> }
> ...
> clnt->cl_p1 = xd; <=== but here we should increment the
> refocunt.
> }
>
> another code section with the same handling.
>
> makefd_xprt()
> {
> ...
> if ((oflags & RPC_DPLX_LKP_OFLAG_ALLOC) || (!rec->hdl.xd)) {
> newxd = true;
> xd = rec->hdl.xd = alloc_x_vc_data();
> ...
> } else {
> xd = (struct x_vc_data *)rec->hdl.xd;
> /* dont return destroyed xprts */
> if (!(xd->flags & X_VC_DATA_FLAG_SVC_DESTROYED)) {
> if (rec->hdl.xprt) {
> xprt = rec->hdl.xprt;
> /* inc xprt refcnt */
> SVC_REF(xprt, SVC_REF_FLAG_NONE);
> } else
> ++(xd->refcnt); <==== not right, no addtl'
> ref to xd taken.
so this looks more likely to be incorrect, need to review
> }
> /* return extra ref */
> rpc_dplx_unref(rec,
> RPC_DPLX_FLAG_LOCKED | RPC_DPLX_FLAG_UNLOCK);
> *allocated = FALSE;
>
> /* return ref'd xprt */
> goto done_xprt;
> }
> ...
> xprt->xp_p1 = xd; <==== but here we should increment the refcount
>
> ...
> }
>
> Both areas handle the refcount'ing wrong, but it might balance out
> sometimes.
>
>
> What do you think ?
>
> Cheers Swen
>
>
--
Matt Benjamin
Red Hat, Inc.
315 West Huron Street, Suite 140A
Ann Arbor, Michigan 48103
http://www.redhat.com/en/technologies/storage
tel. 734-707-0660
fax. 734-769-8938
cel. 734-216-5309
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