Re: [PATCH v4] mm: assert exclusive nid/zonenum bits at the page/folio access sites
From: kernel test robot
Date: Thu Jun 25 2026 - 02:53:32 EST
Hi Hui,
kernel test robot noticed the following build warnings:
[auto build test WARNING on akpm-mm/mm-everything]
url: https://github.com/intel-lab-lkp/linux/commits/Hui-Zhu/mm-assert-exclusive-nid-zonenum-bits-at-the-page-folio-access-sites/20260625-134106
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20260625053958.918738-1-hui.zhu%40linux.dev
patch subject: [PATCH v4] mm: assert exclusive nid/zonenum bits at the page/folio access sites
config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20260625/202606251454.M74ab4Rw-lkp@xxxxxxxxx/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 6cc609bb250b21b47fc7d394b4019101e9983597)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260625/202606251454.M74ab4Rw-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202606251454.M74ab4Rw-lkp@xxxxxxxxx/
All warnings (new ones prefixed by >>):
>> kernel/fork.c:258:18: warning: unused variable 'page' [-Wunused-variable]
258 | struct page *page = vm_area->pages[i];
| ^~~~
1 warning generated.
vim +/page +258 kernel/fork.c
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 240
449e0b4ed5a16c7 Pasha Tatashin 2025-05-09 241 static bool try_release_thread_stack_to_cache(struct vm_struct *vm_area)
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 242 {
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 243 unsigned int i;
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 244 int nid;
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 245
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 246 /*
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 247 * Don't cache stacks if any of the pages don't match the local domain, unless
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 248 * there is no local memory to begin with.
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 249 *
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 250 * Note that lack of local memory does not automatically mean it makes no difference
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 251 * performance-wise which other domain backs the stack. In this case we are merely
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 252 * trying to avoid constantly going to vmalloc.
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 253 */
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 254 scoped_guard(preempt) {
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 255 nid = numa_node_id();
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 256 if (node_state(nid, N_MEMORY)) {
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 257 for (i = 0; i < vm_area->nr_pages; i++) {
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 @258 struct page *page = vm_area->pages[i];
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 259 if (page_to_nid(page) != nid)
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 260 return false;
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 261 }
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 262 }
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 263
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 264 for (i = 0; i < NR_CACHED_STACKS; i++) {
47e39c793367600 Uros Bizjak 2024-05-23 265 struct vm_struct *tmp = NULL;
47e39c793367600 Uros Bizjak 2024-05-23 266
449e0b4ed5a16c7 Pasha Tatashin 2025-05-09 267 if (this_cpu_try_cmpxchg(cached_stacks[i], &tmp, vm_area))
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 268 return true;
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 269 }
262ef8e55b7ccd4 Mateusz Guzik 2025-11-20 270 }
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 271 return false;
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 272 }
e540bf3162e822d Sebastian Andrzej Siewior 2022-02-17 273
--
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