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Wed, 3 Mar 2021 07:33:32 +0000 Received: from BN8PR11MB3586.namprd11.prod.outlook.com ([fe80::382b:3030:cdf0:f4da]) by BN8PR11MB3586.namprd11.prod.outlook.com ([fe80::382b:3030:cdf0:f4da%7]) with mapi id 15.20.3890.029; Wed, 3 Mar 2021 07:33:31 +0000 Subject: Re: [PATCH] vt: keyboard, fix uninitialized variables warning To: Greg KH Cc: jirislaby@kernel.org, andriy.shevchenko@linux.intel.com, dmitry.torokhov@gmail.com, linux-kernel@vger.kernel.org References: <1614747572-3295-1-git-send-email-li.wang@windriver.com> From: "Wang, Li" Message-ID: <5f05c3c2-6c72-140f-fd56-cd9ec1c7c4a1@windriver.com> Date: Wed, 3 Mar 2021 15:33:23 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [60.247.85.82] X-ClientProxiedBy: HK2PR04CA0060.apcprd04.prod.outlook.com (2603:1096:202:14::28) To BN8PR11MB3586.namprd11.prod.outlook.com (2603:10b6:408:84::30) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [128.224.155.135] (60.247.85.82) by HK2PR04CA0060.apcprd04.prod.outlook.com (2603:1096:202:14::28) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3912.17 via Frontend Transport; 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>> ^~~ >> kernel-source/drivers/tty/vt/keyboard.c: warning: 'kbs' may be used uninitialized in this function [-Wmaybe-uninitialized] >> kfree(kbs); >> ^~~~~~~~~~ >> >> Signed-off-by: Li Wang >> --- >> drivers/tty/vt/keyboard.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c >> index 7763862..3e73d55 100644 >> --- a/drivers/tty/vt/keyboard.c >> +++ b/drivers/tty/vt/keyboard.c >> @@ -2049,8 +2049,8 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm) >> { >> unsigned char kb_func; >> unsigned long flags; >> - char *kbs; >> - int ret; >> + char *kbs = NULL; >> + int ret = -EINVAL; >> >> if (get_user(kb_func, &user_kdgkb->kb_func)) >> return -EFAULT; > What compiler is providing these "warnings"? > > Turns out it is impossible to hit, so this isn't actually fixing > anything... I tested it with gcc 8.2 for arm for runtime codes view, indeed it is impossible to hit. but for compiler view, gcc should give 'used uninitialized' warning, too. thank for your reply, LiWang. > > thanks, > > greg k-h