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X-CSE-ConnectionGUID: gJZHgLjTRCmtC4sizZTKMQ== X-CSE-MsgGUID: NrHXdqPQQ4KsHACTmSKkvg== X-IronPort-AV: E=McAfee;i="6800,10657,11771"; a="78163733" X-IronPort-AV: E=Sophos;i="6.23,207,1770624000"; d="scan'208";a="78163733" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2026 17:50:20 -0700 X-CSE-ConnectionGUID: Dqc2zjXCTtqy46pLShY4xQ== X-CSE-MsgGUID: ZFa2OBOTRKu+Z+xEW9/Xqw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,207,1770624000"; d="scan'208";a="233379027" Received: from lkp-server01.sh.intel.com (HELO aa799cca880d) ([10.239.97.150]) by orviesa006.jf.intel.com with ESMTP; 29 Apr 2026 17:50:17 -0700 Received: from kbuild by aa799cca880d with local (Exim 4.98.2) (envelope-from ) id 1wIFba-00000000Bjc-0kyc; Thu, 30 Apr 2026 00:50:14 +0000 Date: Thu, 30 Apr 2026 08:49:23 +0800 From: kernel test robot To: Yue Haibing , davem@davemloft.net, dsahern@kernel.org, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next] ipv6: sit: remove redundant ret = 0 assignment Message-ID: <202604300826.7OKegoUR-lkp@intel.com> References: <20260403084402.4105936-1-yuehaibing@huawei.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260403084402.4105936-1-yuehaibing@huawei.com> Hi Yue, kernel test robot noticed the following build warnings: [auto build test WARNING on net-next/main] url: https://github.com/intel-lab-lkp/linux/commits/Yue-Haibing/ipv6-sit-remove-redundant-ret-0-assignment/20260425-024700 base: net-next/main patch link: https://lore.kernel.org/r/20260403084402.4105936-1-yuehaibing%40huawei.com patch subject: [PATCH net-next] ipv6: sit: remove redundant ret = 0 assignment config: loongarch-defconfig (https://download.01.org/0day-ci/archive/20260430/202604300826.7OKegoUR-lkp@intel.com/config) compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260430/202604300826.7OKegoUR-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot | Closes: https://lore.kernel.org/oe-kbuild-all/202604300826.7OKegoUR-lkp@intel.com/ All warnings (new ones prefixed by >>): >> net/ipv6/sit.c:362:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 362 | if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen)) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ net/ipv6/sit.c:367:9: note: uninitialized use occurs here 367 | return ret; | ^~~ net/ipv6/sit.c:362:2: note: remove the 'if' if its condition is always true 362 | if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen)) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 363 | ret = -EFAULT; net/ipv6/sit.c:312:9: note: initialize the variable 'ret' to silence this warning 312 | int ret; | ^ | = 0 1 warning generated. vim +362 net/ipv6/sit.c fadf6bf0606913 Templin, Fred L 2008-03-11 305 3e7a1c7c561ed8 Arnd Bergmann 2021-07-27 306 static int ipip6_tunnel_get_prl(struct net_device *dev, struct ip_tunnel_prl __user *a) 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 307 { fd5d687b76b325 Christoph Hellwig 2020-05-19 308 struct ip_tunnel *t = netdev_priv(dev); 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 309 struct ip_tunnel_prl kprl, *kp; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 310 struct ip_tunnel_prl_entry *prl; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 311 unsigned int cmax, c = 0, ca, len; 3c6132ccc58e8a Yue Haibing 2026-04-08 312 int ret; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 313 fd5d687b76b325 Christoph Hellwig 2020-05-19 314 if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) fd5d687b76b325 Christoph Hellwig 2020-05-19 315 return -EINVAL; fd5d687b76b325 Christoph Hellwig 2020-05-19 316 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 317 if (copy_from_user(&kprl, a, sizeof(kprl))) 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 318 return -EFAULT; 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 319 cmax = kprl.datalen / sizeof(kprl); 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 320 if (cmax > 1 && kprl.addr != htonl(INADDR_ANY)) 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 321 cmax = 1; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 322 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 323 /* For simple GET or for root users, 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 324 * we try harder to allocate. 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 325 */ 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 326 kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ? 69050f8d6d075d Kees Cook 2026-02-20 327 kzalloc_objs(*kp, cmax, GFP_KERNEL_ACCOUNT | __GFP_NOWARN) : 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 328 NULL; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 329 284fda1eff8a8b kernel test robot 2021-03-27 330 ca = min(t->prl_count, cmax); 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 331 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 332 if (!kp) { 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 333 /* We don't try hard to allocate much memory for 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 334 * non-root users. 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 335 * For root users, retry allocating enough memory for 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 336 * the answer. 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 337 */ 69050f8d6d075d Kees Cook 2026-02-20 338 kp = kzalloc_objs(*kp, ca, 69050f8d6d075d Kees Cook 2026-02-20 339 GFP_ATOMIC | __GFP_ACCOUNT | __GFP_NOWARN); 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 340 if (!kp) { 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 341 ret = -ENOMEM; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 342 goto out; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 343 } 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 344 } 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 345 adabdd8f6acabc katrinzhou 2022-06-28 346 rcu_read_lock(); ef9a9d1183b36f Eric Dumazet 2009-10-23 347 for_each_prl_rcu(t->prl) { 298bf12ddb2584 Sascha Hlusiak 2009-09-29 348 if (c >= cmax) 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 349 break; 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 350 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr) 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 351 continue; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 352 kp[c].addr = prl->addr; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 353 kp[c].flags = prl->flags; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 354 c++; 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 355 if (kprl.addr != htonl(INADDR_ANY)) 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 356 break; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 357 } adabdd8f6acabc katrinzhou 2022-06-28 358 ef9a9d1183b36f Eric Dumazet 2009-10-23 359 rcu_read_unlock(); 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 360 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 361 len = sizeof(*kp) * c; 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 @362 if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen)) 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 363 ret = -EFAULT; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 364 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 365 kfree(kp); adabdd8f6acabc katrinzhou 2022-06-28 366 out: 2b4743bd6be9fe YOSHIFUJI Hideaki 2008-06-16 367 return ret; 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 368 } 300aaeeaab5f44 YOSHIFUJI Hideaki 2008-03-24 369 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki