Re: [kbuild-all] Re: net/sunrpc/svcsock.c:527:32: warning: Variable 'uninitialized_var' is assigned a value that is never used. [unreadVariable]

[Rong Chen]

On 4/9/20 5:35 AM, Chuck Lever wrote:
> > On Apr 8, 2020, at 5:32 PM, kbuild test robot <lkp@xxxxxxxxx> wrote:
> >
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   f5e94d10e4c468357019e5c28d48499f677b284f
> > commit: da1661b93bf489cdbc8bcea919b165d31b4810bf SUNRPC: Teach server to use xprt_sock_sendmsg for socket sends
> > date:   3 weeks ago
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> >
> >
> > cppcheck warnings: (new ones prefixed by >>)
> >
> >    net/sunrpc/svcsock.c:405:9: warning: union member 'Anonymous0::all' is never used. [unusedStructMember]
> >      long  all[SVC_PKTINFO_SPACE / sizeof(long)];
> >            ^
> >    net/sunrpc/svcsock.c:518:9: warning: union member 'Anonymous1::all' is never used. [unusedStructMember]
> >      long  all[SVC_PKTINFO_SPACE / sizeof(long)];
> >            ^
> > > > net/sunrpc/svcsock.c:527:32: warning: Variable 'uninitialized_var' is assigned a value that is never used. [unreadVariable]
> >     unsigned int uninitialized_var(sent);
> >                                   ^
> >
> > vim +/uninitialized_var +527 net/sunrpc/svcsock.c
> >
> >    504	
> >    505	/**
> >    506	 * svc_udp_sendto - Send out a reply on a UDP socket
> >    507	 * @rqstp: completed svc_rqst
> >    508	 *
> >    509	 * Returns the number of bytes sent, or a negative errno.
> >    510	 */
> >    511	static int svc_udp_sendto(struct svc_rqst *rqstp)
> >    512	{
> >    513		struct svc_xprt *xprt = rqstp->rq_xprt;
> >    514		struct svc_sock	*svsk = container_of(xprt, struct svc_sock, sk_xprt);
> >    515		struct xdr_buf *xdr = &rqstp->rq_res;
> >    516		union {
> >    517			struct cmsghdr	hdr;
> >    518			long		all[SVC_PKTINFO_SPACE / sizeof(long)];
> >    519		} buffer;
> >    520		struct cmsghdr *cmh = &buffer.hdr;
> >    521		struct msghdr msg = {
> >    522			.msg_name	= &rqstp->rq_addr,
> >    523			.msg_namelen	= rqstp->rq_addrlen,
> >    524			.msg_control	= cmh,
> >    525			.msg_controllen	= sizeof(buffer),
> >    526		};
> > > 527		unsigned int uninitialized_var(sent);
> >    528		int err;
> >    529	
> >    530		svc_set_cmsg_data(rqstp, cmh);
> >    531	
> >    532		err = xprt_sock_sendmsg(svsk->sk_sock, &msg, xdr, 0, 0, &sent);
> >    533		xdr_free_bvec(xdr);
> >    534		if (err == -ECONNREFUSED) {
> >    535			/* ICMP error on earlier request. */
> >    536			err = xprt_sock_sendmsg(svsk->sk_sock, &msg, xdr, 0, 0, &sent);
> >    537			xdr_free_bvec(xdr);
> >    538		}
> >    539		if (err < 0)
> >    540			return err;
> >    541		return sent;
> Wha? "sent" is used right here. Can someone explain this warning?

Hi Chuck,

Sorry for the inconvenience, it should be a false warning,
It's every odd that removing uninitialized_var can silence this warning.

Best Regards,
Rong Chen

> >    542	}
> >    543	
> >
> > ---
> > 0-DAY CI Kernel Test Service, Intel Corporation
> > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
> --
> Chuck Lever
>
>
> _______________________________________________
> kbuild-all mailing list -- kbuild-all@xxxxxxxxxxxx
> To unsubscribe send an email to kbuild-all-leave@xxxxxxxxxxxx