From: kernel test robot <lkp@intel.com>
To: Harry Yoo <harry.yoo@oracle.com>, venkat88@linux.ibm.com
Cc: 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
Date: Fri, 27 Feb 2026 14:02:59 +0800 [thread overview]
Message-ID: <202602271339.xhIvS2iX-lkp@intel.com> (raw)
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: nios2-allnoconfig (https://download.01.org/0day-ci/archive/20260227/202602271339.xhIvS2iX-lkp@intel.com/config)
compiler: nios2-linux-gcc (GCC) 11.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260227/202602271339.xhIvS2iX-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 <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202602271339.xhIvS2iX-lkp@intel.com/
All errors (new ones prefixed by >>):
mm/slub.c: In function 'slab_pad_check':
>> mm/slub.c:1330:13: error: implicit declaration of function 'obj_exts_in_slab'; did you mean 'obj_exts_in_object'? [-Werror=implicit-function-declaration]
1330 | if (obj_exts_in_slab(s, slab) && !obj_exts_in_object(s, slab)) {
| ^~~~~~~~~~~~~~~~
| obj_exts_in_object
>> mm/slub.c:1332:30: error: implicit declaration of function 'obj_exts_offset_in_slab'; did you mean 'obj_exts_offset_in_object'? [-Werror=implicit-function-declaration]
1332 | remainder -= obj_exts_offset_in_slab(s, slab);
| ^~~~~~~~~~~~~~~~~~~~~~~
| obj_exts_offset_in_object
>> mm/slub.c:1333:30: error: implicit declaration of function 'obj_exts_size_in_slab' [-Werror=implicit-function-declaration]
1333 | remainder -= obj_exts_size_in_slab(slab);
| ^~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
vim +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
next prev parent reply other threads:[~2026-02-27 6:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-23 7:58 [PATCH] mm/slab: initialize slab->stride early to avoid memory ordering issues Harry Yoo
2026-02-23 11:44 ` Harry Yoo
2026-02-23 17:04 ` Vlastimil Babka
2026-02-23 20:23 ` Shakeel Butt
2026-02-24 9:04 ` Venkat Rao Bagalkote
2026-02-24 11:10 ` Harry Yoo
2026-02-25 9:14 ` Venkat Rao Bagalkote
2026-02-25 10:15 ` Harry Yoo
2026-02-27 3:07 ` [PATCH] mm/slab: a debug patch to investigate the issue further Harry Yoo
2026-02-27 5:52 ` kernel test robot
2026-02-27 6:02 ` kernel test robot [this message]
2026-02-27 8:02 ` Venkat Rao Bagalkote
2026-02-27 8:11 ` Harry Yoo
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