2019-03-22 14:07:46

by Arnd Bergmann

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 <[email protected]>
---
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

2019-03-22 15:23:41

by J. Bruce Fields

Subject: Re: [PATCH] nfsd: avoid uninitialized variable warning

On Fri, Mar 22, 2019 at 03:07:11PM +0100, Arnd Bergmann wrote:
> 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.

Thanks, applied.--b.

>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> 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