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X-CSE-ConnectionGUID: 9sBRR7WoSfeVJkTe4J0mlQ== X-CSE-MsgGUID: Zx0N2sP5RcSqJAMYpno3jA== X-IronPort-AV: E=McAfee;i="6800,10657,11713"; a="73121978" X-IronPort-AV: E=Sophos;i="6.21,313,1763452800"; d="scan'208";a="73121978" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Feb 2026 21:52:41 -0800 X-CSE-ConnectionGUID: 62b9Y3uDQlyrKfLirF6oHQ== X-CSE-MsgGUID: vnQDeMXOQSSCRScW/BACmg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,313,1763452800"; d="scan'208";a="214993740" Received: from lkp-server02.sh.intel.com (HELO a3936d6a266d) ([10.239.97.151]) by fmviesa007.fm.intel.com with ESMTP; 26 Feb 2026 21:52:37 -0800 Received: from kbuild by a3936d6a266d with local (Exim 4.98.2) (envelope-from ) id 1vvqmA-00000000AE3-0V4y; Fri, 27 Feb 2026 05:52:34 +0000 Date: Fri, 27 Feb 2026 13:52:18 +0800 From: kernel test robot To: Harry Yoo , venkat88@linux.ibm.com Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, akpm@linux-foundation.org, ast@kernel.org, cgroups@vger.kernel.org, cl@gentwo.org, hannes@cmpxchg.org, hao.li@linux.dev, harry.yoo@oracle.com, linux-mm@kvack.org, mhocko@kernel.org, muchun.song@linux.dev, rientjes@google.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, surenb@google.com, vbabka@suse.cz Subject: Re: [PATCH] mm/slab: a debug patch to investigate the issue further Message-ID: <202602271320.ywOCYQx4-lkp@intel.com> References: <20260227030733.9517-1-harry.yoo@oracle.com> Precedence: bulk X-Mailing-List: cgroups@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: <20260227030733.9517-1-harry.yoo@oracle.com> Hi Harry, kernel test robot noticed the following build errors: [auto build test ERROR on akpm-mm/mm-everything] url: https://github.com/intel-lab-lkp/linux/commits/Harry-Yoo/mm-slab-a-debug-patch-to-investigate-the-issue-further/20260227-111246 base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything patch link: https://lore.kernel.org/r/20260227030733.9517-1-harry.yoo%40oracle.com patch subject: [PATCH] mm/slab: a debug patch to investigate the issue further config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20260227/202602271320.ywOCYQx4-lkp@intel.com/config) compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260227/202602271320.ywOCYQx4-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/202602271320.ywOCYQx4-lkp@intel.com/ All errors (new ones prefixed by >>): >> mm/slub.c:1330:6: error: call to undeclared function 'obj_exts_in_slab'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1330 | if (obj_exts_in_slab(s, slab) && !obj_exts_in_object(s, slab)) { | ^ >> mm/slub.c:1332:16: error: call to undeclared function 'obj_exts_offset_in_slab'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1332 | remainder -= obj_exts_offset_in_slab(s, slab); | ^ mm/slub.c:1332:16: note: did you mean 'obj_exts_offset_in_object'? mm/slub.c:793:28: note: 'obj_exts_offset_in_object' declared here 793 | static inline unsigned int obj_exts_offset_in_object(struct kmem_cache *s) | ^ >> mm/slub.c:1333:16: error: call to undeclared function 'obj_exts_size_in_slab'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1333 | remainder -= obj_exts_size_in_slab(slab); | ^ 3 errors generated. vim +/obj_exts_in_slab +1330 mm/slub.c 81819f0fc8285a Christoph Lameter 2007-05-06 1311 39b264641a0c3b Christoph Lameter 2008-04-14 1312 /* Check the pad bytes at the end of a slab page */ adea9876180664 Ilya Leoshkevich 2024-06-21 1313 static pad_check_attributes void adea9876180664 Ilya Leoshkevich 2024-06-21 1314 slab_pad_check(struct kmem_cache *s, struct slab *slab) 81819f0fc8285a Christoph Lameter 2007-05-06 1315 { 2492268472e7d3 Christoph Lameter 2007-07-17 1316 u8 *start; 2492268472e7d3 Christoph Lameter 2007-07-17 1317 u8 *fault; 2492268472e7d3 Christoph Lameter 2007-07-17 1318 u8 *end; 5d682681f8a2bd Balasubramani Vivekanandan 2018-01-31 1319 u8 *pad; 2492268472e7d3 Christoph Lameter 2007-07-17 1320 int length; 2492268472e7d3 Christoph Lameter 2007-07-17 1321 int remainder; 81819f0fc8285a Christoph Lameter 2007-05-06 1322 81819f0fc8285a Christoph Lameter 2007-05-06 1323 if (!(s->flags & SLAB_POISON)) a204e6d626126d Miaohe Lin 2022-04-19 1324 return; 81819f0fc8285a Christoph Lameter 2007-05-06 1325 bb192ed9aa7191 Vlastimil Babka 2021-11-03 1326 start = slab_address(slab); bb192ed9aa7191 Vlastimil Babka 2021-11-03 1327 length = slab_size(slab); 39b264641a0c3b Christoph Lameter 2008-04-14 1328 end = start + length; 70089d01880750 Harry Yoo 2026-01-13 1329 a77d6d33868502 Harry Yoo 2026-01-13 @1330 if (obj_exts_in_slab(s, slab) && !obj_exts_in_object(s, slab)) { 70089d01880750 Harry Yoo 2026-01-13 1331 remainder = length; 70089d01880750 Harry Yoo 2026-01-13 @1332 remainder -= obj_exts_offset_in_slab(s, slab); 70089d01880750 Harry Yoo 2026-01-13 @1333 remainder -= obj_exts_size_in_slab(slab); 70089d01880750 Harry Yoo 2026-01-13 1334 } else { 39b264641a0c3b Christoph Lameter 2008-04-14 1335 remainder = length % s->size; 70089d01880750 Harry Yoo 2026-01-13 1336 } 70089d01880750 Harry Yoo 2026-01-13 1337 81819f0fc8285a Christoph Lameter 2007-05-06 1338 if (!remainder) a204e6d626126d Miaohe Lin 2022-04-19 1339 return; 81819f0fc8285a Christoph Lameter 2007-05-06 1340 5d682681f8a2bd Balasubramani Vivekanandan 2018-01-31 1341 pad = end - remainder; a79316c6178ca4 Andrey Ryabinin 2015-02-13 1342 metadata_access_enable(); aa1ef4d7b3f67f Andrey Konovalov 2020-12-22 1343 fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder); a79316c6178ca4 Andrey Ryabinin 2015-02-13 1344 metadata_access_disable(); 2492268472e7d3 Christoph Lameter 2007-07-17 1345 if (!fault) a204e6d626126d Miaohe Lin 2022-04-19 1346 return; 2492268472e7d3 Christoph Lameter 2007-07-17 1347 while (end > fault && end[-1] == POISON_INUSE) 2492268472e7d3 Christoph Lameter 2007-07-17 1348 end--; 2492268472e7d3 Christoph Lameter 2007-07-17 1349 3f6f32b14ab354 Hyesoo Yu 2025-02-26 1350 slab_bug(s, "Padding overwritten. 0x%p-0x%p @offset=%tu", e1b70dd1e6429f Miles Chen 2019-11-30 1351 fault, end - 1, fault - start); 5d682681f8a2bd Balasubramani Vivekanandan 2018-01-31 1352 print_section(KERN_ERR, "Padding ", pad, remainder); 3f6f32b14ab354 Hyesoo Yu 2025-02-26 1353 __slab_err(slab); 2492268472e7d3 Christoph Lameter 2007-07-17 1354 5d682681f8a2bd Balasubramani Vivekanandan 2018-01-31 1355 restore_bytes(s, "slab padding", POISON_INUSE, fault, end); 81819f0fc8285a Christoph Lameter 2007-05-06 1356 } 81819f0fc8285a Christoph Lameter 2007-05-06 1357 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki