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a="3501654" X-IronPort-AV: E=Sophos;i="6.27,215,1787036400"; d="scan'208";a="3501654" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Nov 2026 12:44:55 -0800 X-CSE-ConnectionGUID: tuBMvxGOSPOkyB7OPTsXpA== X-CSE-MsgGUID: elTB1/WFSOCf9ocxwmlAiw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,215,1787036400"; d="scan'208";a="9808870" Received: from lkp-server01.sh.intel.com (HELO 0caa9d2d175c) ([10.239.97.150]) by fmviesa007.fm.intel.com with ESMTP; 15 Nov 2026 12:44:52 -0800 Received: from kbuild by 0caa9d2d175c with local (Exim 4.98.2) (envelope-from ) id 1xSh5k-000000017Iq-0ij2; Sun, 15 Nov 2026 20:44:48 +0000 Date: Mon, 16 Nov 2026 04:44:19 +0800 From: kernel test robot To: =?iso-8859-1?Q?Andr=E9?= Almeida , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , Arnd Bergmann , Sebastian Andrzej Siewior , Waiman Long , Ryan Houdek , Thomas Gleixner Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-api@vger.kernel.org, kernel-dev@igalia.com, =?iso-8859-1?Q?Andr=E9?= Almeida Subject: Re: [PATCH v8 10/10] futex: Use new robust list API internally Message-ID: <202611160419.vIdH20Tu-lkp@intel.com> References: <20261115-tonyk-robust_futex-v8-10-a4fe47333a28@igalia.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20261115-tonyk-robust_futex-v8-10-a4fe47333a28@igalia.com> Hi André, kernel test robot noticed the following build warnings: [auto build test WARNING on 9f74092fda91ef93c2b07585785c1dc83cd7971f] url: https://github.com/intel-lab-lkp/linux/commits/Andr-Almeida/futex-Skip-test_futex_robust_unlock-if-not-supported/20261115-143110 base: 9f74092fda91ef93c2b07585785c1dc83cd7971f patch link: https://lore.kernel.org/r/20261115-tonyk-robust_futex-v8-10-a4fe47333a28%40igalia.com patch subject: [PATCH v8 10/10] futex: Use new robust list API internally config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20261116/202611160419.vIdH20Tu-lkp@intel.com/config) compiler: clang version 22.1.8 (https://github.com/llvm/llvm-project ca7933e47d3a3451d81e72ac174dcb5aa28b59d1) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261116/202611160419.vIdH20Tu-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/202611160419.vIdH20Tu-lkp@intel.com/ All warnings (new ones prefixed by >>): >> kernel/futex/syscalls.c:75:6: warning: variable 'head' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 75 | if (index >= 0) { | ^~~~~~~~~~ kernel/futex/syscalls.c:85:9: note: uninitialized use occurs here 85 | return head; | ^~~~ kernel/futex/syscalls.c:75:2: note: remove the 'if' if its condition is always true 75 | if (index >= 0) { | ^~~~~~~~~~~~~~~ kernel/futex/syscalls.c:48:19: note: initialize the variable 'head' to silence this warning 48 | void __user *head; | ^ | = NULL 1 warning generated. vim +75 kernel/futex/syscalls.c af8cc9600bbf22 Peter Zijlstra 2021-09-23 44 5588aabbe40841 André Almeida 2026-11-15 45 static void __user *futex_get_robust_list_common(int pid, bool compat, int index) 6b54082c3ed4dc Pranav Tyagi 2025-09-15 46 { 6b54082c3ed4dc Pranav Tyagi 2025-09-15 47 struct task_struct *p = current; 6b54082c3ed4dc Pranav Tyagi 2025-09-15 48 void __user *head; 6b54082c3ed4dc Pranav Tyagi 2025-09-15 49 int ret; af8cc9600bbf22 Peter Zijlstra 2021-09-23 50 a2d2b7acb53d36 André Almeida 2026-11-15 51 if (index >= FUTEX_ROBUST_LIST2_MAX_IDX) a2d2b7acb53d36 André Almeida 2026-11-15 52 return (void __user *)ERR_PTR(-EINVAL); a2d2b7acb53d36 André Almeida 2026-11-15 53 6b54082c3ed4dc Pranav Tyagi 2025-09-15 54 scoped_guard(rcu) { 6b54082c3ed4dc Pranav Tyagi 2025-09-15 55 if (pid) { af8cc9600bbf22 Peter Zijlstra 2021-09-23 56 p = find_task_by_vpid(pid); af8cc9600bbf22 Peter Zijlstra 2021-09-23 57 if (!p) 6b54082c3ed4dc Pranav Tyagi 2025-09-15 58 return (void __user *)ERR_PTR(-ESRCH); 6b54082c3ed4dc Pranav Tyagi 2025-09-15 59 } 6b54082c3ed4dc Pranav Tyagi 2025-09-15 60 get_task_struct(p); af8cc9600bbf22 Peter Zijlstra 2021-09-23 61 } af8cc9600bbf22 Peter Zijlstra 2021-09-23 62 6b54082c3ed4dc Pranav Tyagi 2025-09-15 63 /* 6b54082c3ed4dc Pranav Tyagi 2025-09-15 64 * Hold exec_update_lock to serialize with concurrent exec() 6b54082c3ed4dc Pranav Tyagi 2025-09-15 65 * so ptrace_may_access() is checked against stable credentials 6b54082c3ed4dc Pranav Tyagi 2025-09-15 66 */ 6b54082c3ed4dc Pranav Tyagi 2025-09-15 67 ret = down_read_killable(&p->signal->exec_update_lock); 6b54082c3ed4dc Pranav Tyagi 2025-09-15 68 if (ret) 6b54082c3ed4dc Pranav Tyagi 2025-09-15 69 goto err_put; 6b54082c3ed4dc Pranav Tyagi 2025-09-15 70 af8cc9600bbf22 Peter Zijlstra 2021-09-23 71 ret = -EPERM; af8cc9600bbf22 Peter Zijlstra 2021-09-23 72 if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS)) af8cc9600bbf22 Peter Zijlstra 2021-09-23 73 goto err_unlock; af8cc9600bbf22 Peter Zijlstra 2021-09-23 74 5588aabbe40841 André Almeida 2026-11-15 @75 if (index >= 0) { 5588aabbe40841 André Almeida 2026-11-15 76 scoped_guard(mutex, &p->futex.exit_mutex) { 5588aabbe40841 André Almeida 2026-11-15 77 uintptr_t *rl = p->futex.robust_lists; 5588aabbe40841 André Almeida 2026-11-15 78 head = rl ? (void __user *) rl[index] : NULL; 5588aabbe40841 André Almeida 2026-11-15 79 } 5588aabbe40841 André Almeida 2026-11-15 80 } af8cc9600bbf22 Peter Zijlstra 2021-09-23 81 6b54082c3ed4dc Pranav Tyagi 2025-09-15 82 up_read(&p->signal->exec_update_lock); 6b54082c3ed4dc Pranav Tyagi 2025-09-15 83 put_task_struct(p); 6b54082c3ed4dc Pranav Tyagi 2025-09-15 84 6b54082c3ed4dc Pranav Tyagi 2025-09-15 85 return head; af8cc9600bbf22 Peter Zijlstra 2021-09-23 86 af8cc9600bbf22 Peter Zijlstra 2021-09-23 87 err_unlock: 6b54082c3ed4dc Pranav Tyagi 2025-09-15 88 up_read(&p->signal->exec_update_lock); 6b54082c3ed4dc Pranav Tyagi 2025-09-15 89 err_put: 6b54082c3ed4dc Pranav Tyagi 2025-09-15 90 put_task_struct(p); 6b54082c3ed4dc Pranav Tyagi 2025-09-15 91 return (void __user *)ERR_PTR(ret); 6b54082c3ed4dc Pranav Tyagi 2025-09-15 92 } af8cc9600bbf22 Peter Zijlstra 2021-09-23 93 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki