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Miller" , Jakub Kicinski , netdev@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: dsa: b53: Fix dereference of null dev Message-ID: <20210612150256.jziw3xhk7i6fyms4@skbuf> References: <20210612144407.60259-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210612144407.60259-1-colin.king@canonical.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 12, 2021 at 03:44:07PM +0100, Colin King wrote: > From: Colin Ian King > > Currently pointer priv is dereferencing dev before dev is being null > checked so a potential null pointer dereference can occur. Fix this > by only assigning and using priv if dev is not-null. > > Addresses-Coverity: ("Dereference before null check") > Fixes: 16994374a6fc ("net: dsa: b53: Make SRAB driver manage port interrupts") > Signed-off-by: Colin Ian King > --- > drivers/net/dsa/b53/b53_srab.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/dsa/b53/b53_srab.c b/drivers/net/dsa/b53/b53_srab.c > index aaa12d73784e..e77ac598f859 100644 > --- a/drivers/net/dsa/b53/b53_srab.c > +++ b/drivers/net/dsa/b53/b53_srab.c > @@ -629,11 +629,13 @@ static int b53_srab_probe(struct platform_device *pdev) > static int b53_srab_remove(struct platform_device *pdev) > { > struct b53_device *dev = platform_get_drvdata(pdev); > - struct b53_srab_priv *priv = dev->priv; > > - b53_srab_intr_set(priv, false); > - if (dev) > + if (dev) { > + struct b53_srab_priv *priv = dev->priv; > + > + b53_srab_intr_set(priv, false); > b53_switch_remove(dev); > + } > > return 0; > } > -- > 2.31.1 > I think the better question is how can "dev" be NULL in the first place, since b53_srab_probe() does an unconditional platform_set_drvdata() with what appears to be a non-NULL dev.