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([101.76.249.46]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2cad77658b5sm25123875ad.50.2026.07.04.10.24.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 04 Jul 2026 10:24:22 -0700 (PDT) From: Guangshuo Li To: Chuck Lever , Jeff Layton , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Guangshuo Li Subject: [PATCH] nfsd: Fix dentry refcount leak in nfsd_set_fh_dentry() Date: Sun, 5 Jul 2026 01:23:00 +0800 Message-ID: <20260704172300.254447-1-lgs201920130244@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" nfsd_set_fh_dentry() gets a dentry reference before checking whether an NFSv2 or NFSv3 filehandle resolves to a V4ROOT export. Such filehandles are rejected, but the rejection path jumps to out before the dentry is stored in fhp->fh_dentry. As a result, fh_put() will not see the dentry, and the out path only drops the export reference. The dentry reference obtained by dget() or exportfs_decode_fh_raw() is therefore leaked. Add a separate error path for the V4ROOT rejection case that drops the dentry reference before dropping the export reference. Fixes: 8a7348a9ed70 ("nfsd: fix refcount leak in nfsd_set_fh_dentry()") Signed-off-by: Guangshuo Li --- fs/nfsd/nfsfh.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index 429ca5c6ec08..2ca5bb5b5e88 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -345,20 +345,22 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqs= tp, struct net *net, fhp->fh_no_wcc =3D true; fhp->fh_64bit_cookies =3D true; if (exp->ex_flags & NFSEXP_V4ROOT) - goto out; + goto out_dput; break; case NFS_FHSIZE: fhp->fh_no_wcc =3D true; if (EX_WGATHER(exp)) fhp->fh_use_wgather =3D true; if (exp->ex_flags & NFSEXP_V4ROOT) - goto out; + goto out_dput; } =20 fhp->fh_dentry =3D dentry; fhp->fh_export =3D exp; =20 return 0; +out_dput: + dput(dentry); out: exp_put(exp); return error; --=20 2.43.0