Date: Wed, 23 Sep 2020 01:56:21 +0000 (UTC) From: Rick Macklem <rmacklem@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r366052 - stable/11/sys/fs/nfsserver Message-ID: <202009230156.08N1uLg7085183@repo.freebsd.org>
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Author: rmacklem Date: Wed Sep 23 01:56:21 2020 New Revision: 366052 URL: https://svnweb.freebsd.org/changeset/base/366052 Log: MFC: r365789 Fix a LOR between the NFS server and server side krpc. Recent testing of the NFS-over-TLS code found a LOR between the mutex lock used for sessions and the sleep lock used for server side krpc socket structures. The code in nfsrv_checksequence() would call SVC_RELEASE() with the mutex held. Normally this is ok, since all that happens is SVC_RELEASE() decrements a reference count. However, if the socket has just been shut down, SVC_RELEASE() drops the reference count to 0 and acquires a sleep lock during destruction of the server side krpc structure. This patch fixes the problem by moving the SVC_RELEASE() call in nfsrv_checksequence() down a few lines to below where the mutex is released. Modified: stable/11/sys/fs/nfsserver/nfs_nfsdstate.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/fs/nfsserver/nfs_nfsdstate.c ============================================================================== --- stable/11/sys/fs/nfsserver/nfs_nfsdstate.c Wed Sep 23 01:51:01 2020 (r366051) +++ stable/11/sys/fs/nfsserver/nfs_nfsdstate.c Wed Sep 23 01:56:21 2020 (r366052) @@ -6091,6 +6091,7 @@ nfsrv_checksequence(struct nfsrv_descript *nd, uint32_ * bound as well, do the implicit binding unless a * BindConnectiontoSession has already been done on the session. */ + savxprt = NULL; if (sep->sess_clp->lc_req.nr_client != NULL && sep->sess_cbsess.nfsess_xprt != nd->nd_xprt && (sep->sess_crflags & NFSV4CRSESS_CONNBACKCHAN) != 0 && @@ -6103,14 +6104,14 @@ nfsrv_checksequence(struct nfsrv_descript *nd, uint32_ sep->sess_clp->lc_req.nr_client->cl_private; nd->nd_xprt->xp_idletimeout = 0; /* Disable timeout. */ sep->sess_cbsess.nfsess_xprt = nd->nd_xprt; - if (savxprt != NULL) - SVC_RELEASE(savxprt); } *sflagsp = 0; if (sep->sess_clp->lc_req.nr_client == NULL) *sflagsp |= NFSV4SEQ_CBPATHDOWN; NFSUNLOCKSESSION(shp); + if (savxprt != NULL) + SVC_RELEASE(savxprt); if (error == NFSERR_EXPIRED) { *sflagsp |= NFSV4SEQ_EXPIREDALLSTATEREVOKED; error = 0;
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