The branch stable/12 has been updated by rmacklem: URL: https://cgit.FreeBSD.org/src/commit/?id=6ae32cc8182f4a48f0606f4b561a98010e1946b8
commit 6ae32cc8182f4a48f0606f4b561a98010e1946b8 Author: Rick Macklem <[email protected]> AuthorDate: 2021-06-11 23:57:14 +0000 Commit: Rick Macklem <[email protected]> CommitDate: 2021-06-26 23:36:37 +0000 krpc: Acquire ref count of CLIENT for backchannel use Michael Dexter <[email protected]> reported a crash in FreeNAS, where the first argument to clnt_bck_svccall() was no longer valid. This argument is a pointer to the callback CLIENT structure, which is free'd when the associated NFSv4 ClientID is free'd. This appears to have occurred because a callback reply was still in the socket receive queue when the CLIENT structure was free'd. This patch acquires a reference count on the CLIENT that is not CLNT_RELEASE()'d until the socket structure is destroyed. This should guarantee that the CLIENT structure is still valid when clnt_bck_svccall() is called. It also adds a check for closed or closing to clnt_bck_svccall() so that it will not process the callback RPC reply message after the ClientID is free'd. (cherry picked from commit e1a907a25cfa422c0d1acaf9f91352ada04f4bca) --- sys/fs/nfsserver/nfs_nfsdstate.c | 8 ++++---- sys/rpc/clnt_bck.c | 13 ++++++++++++- sys/rpc/svc.h | 5 +++++ sys/rpc/svc_vc.c | 4 ++++ 4 files changed, 25 insertions(+), 5 deletions(-) diff --git a/sys/fs/nfsserver/nfs_nfsdstate.c b/sys/fs/nfsserver/nfs_nfsdstate.c index abd4099a7ee2..3423eddc7366 100644 --- a/sys/fs/nfsserver/nfs_nfsdstate.c +++ b/sys/fs/nfsserver/nfs_nfsdstate.c @@ -722,8 +722,8 @@ nfsrv_getclient(nfsquad_t clientid, int opflags, struct nfsclient **clpp, cbprogram, NFSV4_CBVERS); if (clp->lc_req.nr_client != NULL) { SVC_ACQUIRE(nd->nd_xprt); - nd->nd_xprt->xp_p2 = - clp->lc_req.nr_client->cl_private; + CLNT_ACQUIRE(clp->lc_req.nr_client); + nd->nd_xprt->xp_p2 = clp->lc_req.nr_client; /* Disable idle timeout. */ nd->nd_xprt->xp_idletimeout = 0; nsep->sess_cbsess.nfsess_xprt = nd->nd_xprt; @@ -6440,8 +6440,8 @@ nfsrv_bindconnsess(struct nfsrv_descript *nd, uint8_t *sessionid, int *foreaftp) "backchannel\n"); savxprt = sep->sess_cbsess.nfsess_xprt; SVC_ACQUIRE(nd->nd_xprt); - nd->nd_xprt->xp_p2 = - clp->lc_req.nr_client->cl_private; + CLNT_ACQUIRE(clp->lc_req.nr_client); + nd->nd_xprt->xp_p2 = clp->lc_req.nr_client; /* Disable idle timeout. */ nd->nd_xprt->xp_idletimeout = 0; sep->sess_cbsess.nfsess_xprt = nd->nd_xprt; diff --git a/sys/rpc/clnt_bck.c b/sys/rpc/clnt_bck.c index 66f3c308e8e1..7e4a28f229e5 100644 --- a/sys/rpc/clnt_bck.c +++ b/sys/rpc/clnt_bck.c @@ -546,15 +546,26 @@ clnt_bck_destroy(CLIENT *cl) /* * This call is done by the svc code when a backchannel RPC reply is * received. + * For the server end, where callback RPCs to the client are performed, + * xp_p2 points to the "CLIENT" and not the associated "struct ct_data" + * so that svc_vc_destroy() can CLNT_RELEASE() the reference count on it. */ void clnt_bck_svccall(void *arg, struct mbuf *mrep, uint32_t xid) { - struct ct_data *ct = (struct ct_data *)arg; + CLIENT *cl = (CLIENT *)arg; + struct ct_data *ct; struct ct_request *cr; int foundreq; + ct = (struct ct_data *)cl->cl_private; mtx_lock(&ct->ct_lock); + if (ct->ct_closing || ct->ct_closed) { + mtx_unlock(&ct->ct_lock); + m_freem(mrep); + return; + } + ct->ct_upcallrefs++; /* * See if we can match this reply to a request. diff --git a/sys/rpc/svc.h b/sys/rpc/svc.h index b60b85ef0f53..f5e3fcad3ff1 100644 --- a/sys/rpc/svc.h +++ b/sys/rpc/svc.h @@ -148,6 +148,11 @@ struct __rpc_svcthread; * reference count which tracks the number of currently assigned * worker threads plus one for the service pool's reference. * For NFSv4.1 sessions, a reference is also held for a backchannel. + * xp_p2 - Points to the CLIENT structure for the RPC server end + * (the client end for callbacks). + * Points to the private structure (cl_private) for the + * CLIENT structure for the RPC client end (the server + * end for callbacks). */ typedef struct __rpc_svcxprt { #ifdef _KERNEL diff --git a/sys/rpc/svc_vc.c b/sys/rpc/svc_vc.c index dd6b801f44be..f1546615d2df 100644 --- a/sys/rpc/svc_vc.c +++ b/sys/rpc/svc_vc.c @@ -474,6 +474,7 @@ static void svc_vc_destroy(SVCXPRT *xprt) { struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1; + CLIENT *cl = (CLIENT *)xprt->xp_p2; SOCKBUF_LOCK(&xprt->xp_socket->so_rcv); if (xprt->xp_upcallset) { @@ -482,6 +483,9 @@ svc_vc_destroy(SVCXPRT *xprt) } SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv); + if (cl != NULL) + CLNT_RELEASE(cl); + svc_vc_destroy_common(xprt); if (cd->mreq) _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all To unsubscribe, send any mail to "[email protected]"
