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Tue, 12 Jun 2018 03:11:11 -0700 (PDT) Subject: Re: [PATCH] isdn/i4l: add error handling for try_module_get To: Zhouyang Jia Cc: Karsten Keil , Kees Cook , Annie Cherkaev , Al Viro , Jiten Thakkar , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1528778635-41763-1-git-send-email-jiazhouyang09@gmail.com> From: Sergei Shtylyov Message-ID: <5a6a774c-156e-3e13-eda8-ed6c81722888@cogentembedded.com> Date: Tue, 12 Jun 2018 13:11:13 +0300 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <1528778635-41763-1-git-send-email-jiazhouyang09@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/12/2018 7:43 AM, Zhouyang Jia wrote: > When try_module_get fails, the lack of error-handling code may > cause unexpected results. > > This patch adds error-handling code after calling try_module_get. > > Signed-off-by: Zhouyang Jia > --- > drivers/isdn/i4l/isdn_common.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/isdn/i4l/isdn_common.c b/drivers/isdn/i4l/isdn_common.c > index 7c6f3f5..7e52851 100644 > --- a/drivers/isdn/i4l/isdn_common.c > +++ b/drivers/isdn/i4l/isdn_common.c > @@ -71,7 +71,8 @@ static int isdn_add_channels(isdn_driver_t *d, int drvidx, int n, int adding); > static inline void > isdn_lock_driver(isdn_driver_t *drv) > { > - try_module_get(drv->interface->owner); > + if (!try_module_get(drv->interface->owner)) > + printk(KERN_WARNING "isdn_lock_driver: cannot get module\n"); Do you call this error handling code? :-) And BTW we have pr_warn() for that. > drv->locks++; > } > MBR, Sergei