From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH net-next] net/smc: cast sizeof to int for comparison References: <20180915100036.20100-1-yuehaibing@huawei.com> <554a145a-d59d-9033-1702-4987a9c4bc94@linux.ibm.com> From: YueHaibing Message-ID: Date: Mon, 17 Sep 2018 17:38:41 +0800 MIME-Version: 1.0 In-Reply-To: <554a145a-d59d-9033-1702-4987a9c4bc94@linux.ibm.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Ursula Braun Cc: davem@davemloft.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org List-ID: On 2018/9/17 16:49, Ursula Braun wrote: > > > On 09/15/2018 12:00 PM, YueHaibing wrote: >> Comparing an int to a size, which is unsigned, causes the int to become >> unsigned, giving the wrong result. kernel_sendmsg can return a negative >> error code. >> > > Thanks for reporting this issue! > >> Signed-off-by: YueHaibing >> --- >> net/smc/smc_clc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c >> index 83aba9a..fd0f5ce 100644 >> --- a/net/smc/smc_clc.c >> +++ b/net/smc/smc_clc.c >> @@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type, >> vec[i++].iov_len = sizeof(trl); >> /* due to the few bytes needed for clc-handshake this cannot block */ >> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen); >> - if (len < sizeof(pclc)) { >> + if (len < (int)sizeof(pclc)) { >> if (len >= 0) { >> reason_code = -ENETUNREACH; >> smc->sk.sk_err = -reason_code; >> > > Your fix helps, but I would like to follow the hint of Andreas Schwab, and split > the return value check like this: > > --- > net/smc/smc_clc.c | 14 ++++++-------- > 1 file changed, 6 insertions(+), 8 deletions(-) > > --- a/net/smc/smc_clc.c > +++ b/net/smc/smc_clc.c > @@ -446,14 +446,12 @@ int smc_clc_send_proposal(struct smc_soc > vec[i++].iov_len = sizeof(trl); > /* due to the few bytes needed for clc-handshake this cannot block */ > len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen); > - if (len < sizeof(pclc)) { > - if (len >= 0) { > - reason_code = -ENETUNREACH; > - smc->sk.sk_err = -reason_code; > - } else { > - smc->sk.sk_err = smc->clcsock->sk->sk_err; > - reason_code = -smc->sk.sk_err; > - } > + if (len < 0) { > + smc->sk.sk_err = smc->clcsock->sk->sk_err; > + reason_code = -smc->sk.sk_err; > + } else if (len < (int)sizeof(pclc)) { > + reason_code = -ENETUNREACH; > + smc->sk.sk_err = -reason_code; > } > > return reason_code; > > Agreed? Yes, Need a new patch from me? > > Regards, Ursula > > >