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Mon, 23 Aug 2021 12:34:55 -0700 (PDT) Subject: Re: [PATCH Linux-next] ioctl_linux: fix a potential NULL pointer dereference bug To: cgel.zte@gmail.com, gregkh@linuxfoundation.org Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, xu xin , Zeal Robot References: <20210823030631.45517-1-xu.xin16@zte.com.cn> From: Pavel Skripkin Message-ID: <23609ad3-68bb-6df6-609d-5630597c7e0f@gmail.com> Date: Mon, 23 Aug 2021 22:34:54 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20210823030631.45517-1-xu.xin16@zte.com.cn> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/23/21 6:06 AM, cgel.zte@gmail.com wrote: > From: xu xin > > The pointer might be NULL, but it is dereferenced. > > Reported-by: Zeal Robot > Signed-off-by: xu xin > --- > drivers/staging/r8188eu/os_dep/ioctl_linux.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/r8188eu/os_dep/ioctl_linux.c b/drivers/staging/r8188eu/os_dep/ioctl_linux.c > index a3e6d761e748..ce4ce9190f5f 100644 > --- a/drivers/staging/r8188eu/os_dep/ioctl_linux.c > +++ b/drivers/staging/r8188eu/os_dep/ioctl_linux.c > @@ -4389,7 +4389,8 @@ static int rtw_dbg_port(struct net_device *dev, > pregpriv->rx_stbc = extra_arg; > DBG_88E("set rx_stbc =%d\n", pregpriv->rx_stbc); > } else { > - DBG_88E("get rx_stbc =%d\n", pregpriv->rx_stbc); > + if (pregpriv) > + DBG_88E("get rx_stbc =%d\n", pregpriv->rx_stbc); > } > } > break; > @@ -4401,7 +4402,8 @@ static int rtw_dbg_port(struct net_device *dev, > pregpriv->ampdu_enable = extra_arg; > DBG_88E("set ampdu_enable =%d\n", pregpriv->ampdu_enable); > } else { > - DBG_88E("get ampdu_enable =%d\n", pregpriv->ampdu_enable); > + if (pregpriv) > + DBG_88E("get ampdu_enable =%d\n", pregpriv->ampdu_enable); > } > } > break; > Hi, Xu! I can't see how pregpriv can be NULL: struct registry_priv *pregpriv = &padapter->registrypriv; It can be NULL in case of completely wrong padapter pointer, but I can't see how it's possible. Do you have a calltrace? I guess, your robot reported this, because there is useless check in same code block: if (pregpriv && (extra_arg == 0 || extra_arg == 1 || extra_arg == 2 || extra_arg == 3)) So, I think, "pregpriv &&" part should be removed, instead of adding 2 branches. Also, subject line should be "staging: r8118eu: ". Thank you! With regards, Pavel Skripkin