linux-kernel - [PATCH] nfsd: avoid uninitialized variable warning

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Message-Id: <20190322140726.251521-1-arnd@arndb.de>
Date:   Fri, 22 Mar 2019 15:07:11 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     "J. Bruce Fields" <bfields@...ldses.org>,
        Jeff Layton <jlayton@...nel.org>
Cc:     clang-built-linux@...glegroups.com,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Nathan Chancellor <natechancellor@...il.com>,
        Arnd Bergmann <arnd@...db.de>,
        Olga Kornievskaia <kolga@...app.com>,
        Chuck Lever <chuck.lever@...cle.com>,
        Scott Mayhew <smayhew@...hat.com>, linux-nfs@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] nfsd: avoid uninitialized variable warning

clang warns that 'contextlen' may be accessed without an initialization:

fs/nfsd/nfs4xdr.c:2911:9: error: variable 'contextlen' is uninitialized when used here [-Werror,-Wuninitialized]
                                                                contextlen);
                                                                ^~~~~~~~~~
fs/nfsd/nfs4xdr.c:2424:16: note: initialize the variable 'contextlen' to silence this warning
        int contextlen;
                      ^
                       = 0

Presumably this cannot happen, as FATTR4_WORD2_SECURITY_LABEL is
set if CONFIG_NFSD_V4_SECURITY_LABEL is enabled.
Adding another #ifdef like the other two in this function
avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 fs/nfsd/nfs4xdr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 3de42a729093..a3a3455826aa 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2420,8 +2420,10 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	__be32 status;
 	int err;
 	struct nfs4_acl *acl = NULL;
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	void *context = NULL;
 	int contextlen;
+#endif
 	bool contextsupport = false;
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
 	u32 minorversion = resp->cstate.minorversion;
@@ -2906,12 +2908,14 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 			*p++ = cpu_to_be32(NFS4_CHANGE_TYPE_IS_TIME_METADATA);
 	}
 
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
 		status = nfsd4_encode_security_label(xdr, rqstp, context,
 								contextlen);
 		if (status)
 			goto out;
 	}
+#endif
 
 	attrlen = htonl(xdr->buf->len - attrlen_offset - 4);
 	write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, 4);
-- 
2.20.0