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Mon, 08 Apr 2019 15:33:36 -0700 (PDT) Date: Mon, 8 Apr 2019 15:33:34 -0700 From: Nathan Chancellor To: Arnd Bergmann Cc: Martin Schwidefsky , Heiko Carstens , Julian Wiedmann , Ursula Braun , clang-built-linux@googlegroups.com, Nick Desaulniers , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 06/12] s390: ctcm: fix ctcm_new_device error return code Message-ID: <20190408223334.GD18333@archlinux-i9> References: <20190408212648.2407234-1-arnd@arndb.de> <20190408212648.2407234-6-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190408212648.2407234-6-arnd@arndb.de> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 08, 2019 at 11:26:19PM +0200, Arnd Bergmann wrote: > clang points out that the return code from this function is > undefined for one of the error paths: > > ../drivers/s390/net/ctcm_main.c:1595:7: warning: variable 'result' is used uninitialized whenever 'if' condition is true > [-Wsometimes-uninitialized] > if (priv->channel[direction] == NULL) { > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ../drivers/s390/net/ctcm_main.c:1638:9: note: uninitialized use occurs here > return result; > ^~~~~~ > ../drivers/s390/net/ctcm_main.c:1595:3: note: remove the 'if' if its condition is always false > if (priv->channel[direction] == NULL) { > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ../drivers/s390/net/ctcm_main.c:1539:12: note: initialize the variable 'result' to silence this warning > int result; > ^ > > Make it return -ENODEV here, as in the related failure cases. > gcc has a known bug in underreporting some of these warnings > when it has already eliminated the assignment of the return code > based on some earlier optimization step. > > Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor > --- > drivers/s390/net/ctcm_main.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c > index 7617d21cb296..f63c5c871d3d 100644 > --- a/drivers/s390/net/ctcm_main.c > +++ b/drivers/s390/net/ctcm_main.c > @@ -1595,6 +1595,7 @@ static int ctcm_new_device(struct ccwgroup_device *cgdev) > if (priv->channel[direction] == NULL) { > if (direction == CTCM_WRITE) > channel_free(priv->channel[CTCM_READ]); > + result = -ENODEV; > goto out_dev; > } > priv->channel[direction]->netdev = dev; > -- > 2.20.0 >