* [akpm-mm:mm-new 259/263] mm/vmscan.c:1046:6: warning: variable 'target_nid' is uninitialized when used here
@ 2026-01-09 4:34 kernel test robot
0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2026-01-09 4:34 UTC (permalink / raw)
To: Bing Jiao
Cc: oe-kbuild-all, David Hildenbrand, Andrew Morton,
Linux Memory Management List
tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-new
head: ba756a5e4580859e0b26f6679d882f81935a7b14
commit: d92027a5f30a6c5c582169114b1e56d6536ca8f8 [259/263] mm/vmscan: select the closest preferred node in demote_folio_list()
config: i386-allnoconfig-bpf (https://download.01.org/0day-ci/archive/20260109/202601090508.cVHh3bJo-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/20260109/202601090508.cVHh3bJo-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/202601090508.cVHh3bJo-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> mm/vmscan.c:1046:6: warning: variable 'target_nid' is uninitialized when used here [-Wuninitialized]
1046 | if (target_nid == NUMA_NO_NODE)
| ^~~~~~~~~~
mm/vmscan.c:1026:16: note: initialize the variable 'target_nid' to silence this warning
1026 | int target_nid;
| ^
| = 0
1 warning generated.
vim +/target_nid +1046 mm/vmscan.c
26aa2d199d6f2c Dave Hansen 2021-09-02 1017
26aa2d199d6f2c Dave Hansen 2021-09-02 1018 /*
49fd9b6df54e61 Matthew Wilcox (Oracle 2022-09-02 1019) * Take folios on @demote_folios and attempt to demote them to another node.
49fd9b6df54e61 Matthew Wilcox (Oracle 2022-09-02 1020) * Folios which are not demoted are left on @demote_folios.
26aa2d199d6f2c Dave Hansen 2021-09-02 1021 */
49fd9b6df54e61 Matthew Wilcox (Oracle 2022-09-02 1022) static unsigned int demote_folio_list(struct list_head *demote_folios,
059c4bb2dc3b93 Bing Jiao 2026-01-08 1023 struct pglist_data *pgdat,
059c4bb2dc3b93 Bing Jiao 2026-01-08 1024 struct mem_cgroup *memcg)
26aa2d199d6f2c Dave Hansen 2021-09-02 1025 {
d92027a5f30a6c Bing Jiao 2026-01-08 1026 int target_nid;
26aa2d199d6f2c Dave Hansen 2021-09-02 1027 unsigned int nr_succeeded;
32008027289239 Jagdish Gediya 2022-08-18 1028 nodemask_t allowed_mask;
d92027a5f30a6c Bing Jiao 2026-01-08 1029 nodemask_t preferred;
32008027289239 Jagdish Gediya 2022-08-18 1030
32008027289239 Jagdish Gediya 2022-08-18 1031 struct migration_target_control mtc = {
32008027289239 Jagdish Gediya 2022-08-18 1032 /*
32008027289239 Jagdish Gediya 2022-08-18 1033 * Allocate from 'node', or fail quickly and quietly.
32008027289239 Jagdish Gediya 2022-08-18 1034 * When this happens, 'page' will likely just be discarded
32008027289239 Jagdish Gediya 2022-08-18 1035 * instead of migrated.
32008027289239 Jagdish Gediya 2022-08-18 1036 */
bd63d0fde2a2c3 Fushuai Wang 2025-10-06 1037 .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) |
32008027289239 Jagdish Gediya 2022-08-18 1038 __GFP_NOMEMALLOC | GFP_NOWAIT,
e42dfe4e0a51b4 Baolin Wang 2024-03-06 1039 .nmask = &allowed_mask,
e42dfe4e0a51b4 Baolin Wang 2024-03-06 1040 .reason = MR_DEMOTION,
32008027289239 Jagdish Gediya 2022-08-18 1041 };
26aa2d199d6f2c Dave Hansen 2021-09-02 1042
49fd9b6df54e61 Matthew Wilcox (Oracle 2022-09-02 1043) if (list_empty(demote_folios))
26aa2d199d6f2c Dave Hansen 2021-09-02 1044 return 0;
26aa2d199d6f2c Dave Hansen 2021-09-02 1045
26aa2d199d6f2c Dave Hansen 2021-09-02 @1046 if (target_nid == NUMA_NO_NODE)
059c4bb2dc3b93 Bing Jiao 2026-01-08 1047 /* No lower-tier nodes or nodes were hot-unplugged. */
26aa2d199d6f2c Dave Hansen 2021-09-02 1048 return 0;
26aa2d199d6f2c Dave Hansen 2021-09-02 1049
32008027289239 Jagdish Gediya 2022-08-18 1050 node_get_allowed_targets(pgdat, &allowed_mask);
059c4bb2dc3b93 Bing Jiao 2026-01-08 1051 mem_cgroup_node_filter_allowed(memcg, &allowed_mask);
059c4bb2dc3b93 Bing Jiao 2026-01-08 1052 if (nodes_empty(allowed_mask))
059c4bb2dc3b93 Bing Jiao 2026-01-08 1053 return 0;
059c4bb2dc3b93 Bing Jiao 2026-01-08 1054
d92027a5f30a6c Bing Jiao 2026-01-08 1055 target_nid = next_demotion_node(pgdat->node_id, &preferred);
d92027a5f30a6c Bing Jiao 2026-01-08 1056 while (target_nid != NUMA_NO_NODE &&
d92027a5f30a6c Bing Jiao 2026-01-08 1057 !node_isset(target_nid, allowed_mask)) {
d92027a5f30a6c Bing Jiao 2026-01-08 1058 /* Filter out preferred nodes that are not in allowed. */
d92027a5f30a6c Bing Jiao 2026-01-08 1059 nodes_and(preferred, preferred, allowed_mask);
d92027a5f30a6c Bing Jiao 2026-01-08 1060 if (!nodes_empty(preferred)) {
d92027a5f30a6c Bing Jiao 2026-01-08 1061 /* Randomly select one node from preferred. */
d92027a5f30a6c Bing Jiao 2026-01-08 1062 target_nid = node_random(&preferred);
d92027a5f30a6c Bing Jiao 2026-01-08 1063 break;
d92027a5f30a6c Bing Jiao 2026-01-08 1064 }
d92027a5f30a6c Bing Jiao 2026-01-08 1065 /*
d92027a5f30a6c Bing Jiao 2026-01-08 1066 * Preferred nodes in the lower tier are not set in allowed.
d92027a5f30a6c Bing Jiao 2026-01-08 1067 * Recursively get preferred from the next lower tier.
d92027a5f30a6c Bing Jiao 2026-01-08 1068 */
d92027a5f30a6c Bing Jiao 2026-01-08 1069 target_nid = next_demotion_node(target_nid, &preferred);
d92027a5f30a6c Bing Jiao 2026-01-08 1070 }
d92027a5f30a6c Bing Jiao 2026-01-08 1071
d92027a5f30a6c Bing Jiao 2026-01-08 1072 if (target_nid == NUMA_NO_NODE)
d92027a5f30a6c Bing Jiao 2026-01-08 1073 /* Nodes are gone (e.g., hot-unplugged). */
d92027a5f30a6c Bing Jiao 2026-01-08 1074 return 0;
059c4bb2dc3b93 Bing Jiao 2026-01-08 1075 mtc.nid = target_nid;
32008027289239 Jagdish Gediya 2022-08-18 1076
26aa2d199d6f2c Dave Hansen 2021-09-02 1077 /* Demotion ignores all cpuset and mempolicy settings */
29ea04095b9697 SeongJae Park 2025-06-16 1078 migrate_pages(demote_folios, alloc_demote_folio, NULL,
32008027289239 Jagdish Gediya 2022-08-18 1079 (unsigned long)&mtc, MIGRATE_ASYNC, MR_DEMOTION,
26aa2d199d6f2c Dave Hansen 2021-09-02 1080 &nr_succeeded);
26aa2d199d6f2c Dave Hansen 2021-09-02 1081
26aa2d199d6f2c Dave Hansen 2021-09-02 1082 return nr_succeeded;
26aa2d199d6f2c Dave Hansen 2021-09-02 1083 }
26aa2d199d6f2c Dave Hansen 2021-09-02 1084
:::::: The code at line 1046 was first introduced by commit
:::::: 26aa2d199d6f2cfa6f2ef2a5dfe891f2250e71a0 mm/migrate: demote pages during reclaim
:::::: TO: Dave Hansen <dave.hansen@linux.intel.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 2+ messages in thread
* [akpm-mm:mm-new 259/263] mm/vmscan.c:1046:6: warning: variable 'target_nid' is uninitialized when used here
@ 2026-01-09 2:24 kernel test robot
0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2026-01-09 2:24 UTC (permalink / raw)
To: Bing Jiao
Cc: llvm, oe-kbuild-all, David Hildenbrand, Andrew Morton,
Linux Memory Management List
tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-new
head: ba756a5e4580859e0b26f6679d882f81935a7b14
commit: d92027a5f30a6c5c582169114b1e56d6536ca8f8 [259/263] mm/vmscan: select the closest preferred node in demote_folio_list()
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20260109/202601091037.vUSHeJCH-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/20260109/202601091037.vUSHeJCH-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/202601091037.vUSHeJCH-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> mm/vmscan.c:1046:6: warning: variable 'target_nid' is uninitialized when used here [-Wuninitialized]
1046 | if (target_nid == NUMA_NO_NODE)
| ^~~~~~~~~~
mm/vmscan.c:1026:16: note: initialize the variable 'target_nid' to silence this warning
1026 | int target_nid;
| ^
| = 0
1 warning generated.
vim +/target_nid +1046 mm/vmscan.c
26aa2d199d6f2c Dave Hansen 2021-09-02 1017
26aa2d199d6f2c Dave Hansen 2021-09-02 1018 /*
49fd9b6df54e61 Matthew Wilcox (Oracle 2022-09-02 1019) * Take folios on @demote_folios and attempt to demote them to another node.
49fd9b6df54e61 Matthew Wilcox (Oracle 2022-09-02 1020) * Folios which are not demoted are left on @demote_folios.
26aa2d199d6f2c Dave Hansen 2021-09-02 1021 */
49fd9b6df54e61 Matthew Wilcox (Oracle 2022-09-02 1022) static unsigned int demote_folio_list(struct list_head *demote_folios,
059c4bb2dc3b93 Bing Jiao 2026-01-08 1023 struct pglist_data *pgdat,
059c4bb2dc3b93 Bing Jiao 2026-01-08 1024 struct mem_cgroup *memcg)
26aa2d199d6f2c Dave Hansen 2021-09-02 1025 {
d92027a5f30a6c Bing Jiao 2026-01-08 1026 int target_nid;
26aa2d199d6f2c Dave Hansen 2021-09-02 1027 unsigned int nr_succeeded;
32008027289239 Jagdish Gediya 2022-08-18 1028 nodemask_t allowed_mask;
d92027a5f30a6c Bing Jiao 2026-01-08 1029 nodemask_t preferred;
32008027289239 Jagdish Gediya 2022-08-18 1030
32008027289239 Jagdish Gediya 2022-08-18 1031 struct migration_target_control mtc = {
32008027289239 Jagdish Gediya 2022-08-18 1032 /*
32008027289239 Jagdish Gediya 2022-08-18 1033 * Allocate from 'node', or fail quickly and quietly.
32008027289239 Jagdish Gediya 2022-08-18 1034 * When this happens, 'page' will likely just be discarded
32008027289239 Jagdish Gediya 2022-08-18 1035 * instead of migrated.
32008027289239 Jagdish Gediya 2022-08-18 1036 */
bd63d0fde2a2c3 Fushuai Wang 2025-10-06 1037 .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) |
32008027289239 Jagdish Gediya 2022-08-18 1038 __GFP_NOMEMALLOC | GFP_NOWAIT,
e42dfe4e0a51b4 Baolin Wang 2024-03-06 1039 .nmask = &allowed_mask,
e42dfe4e0a51b4 Baolin Wang 2024-03-06 1040 .reason = MR_DEMOTION,
32008027289239 Jagdish Gediya 2022-08-18 1041 };
26aa2d199d6f2c Dave Hansen 2021-09-02 1042
49fd9b6df54e61 Matthew Wilcox (Oracle 2022-09-02 1043) if (list_empty(demote_folios))
26aa2d199d6f2c Dave Hansen 2021-09-02 1044 return 0;
26aa2d199d6f2c Dave Hansen 2021-09-02 1045
26aa2d199d6f2c Dave Hansen 2021-09-02 @1046 if (target_nid == NUMA_NO_NODE)
059c4bb2dc3b93 Bing Jiao 2026-01-08 1047 /* No lower-tier nodes or nodes were hot-unplugged. */
26aa2d199d6f2c Dave Hansen 2021-09-02 1048 return 0;
26aa2d199d6f2c Dave Hansen 2021-09-02 1049
32008027289239 Jagdish Gediya 2022-08-18 1050 node_get_allowed_targets(pgdat, &allowed_mask);
059c4bb2dc3b93 Bing Jiao 2026-01-08 1051 mem_cgroup_node_filter_allowed(memcg, &allowed_mask);
059c4bb2dc3b93 Bing Jiao 2026-01-08 1052 if (nodes_empty(allowed_mask))
059c4bb2dc3b93 Bing Jiao 2026-01-08 1053 return 0;
059c4bb2dc3b93 Bing Jiao 2026-01-08 1054
d92027a5f30a6c Bing Jiao 2026-01-08 1055 target_nid = next_demotion_node(pgdat->node_id, &preferred);
d92027a5f30a6c Bing Jiao 2026-01-08 1056 while (target_nid != NUMA_NO_NODE &&
d92027a5f30a6c Bing Jiao 2026-01-08 1057 !node_isset(target_nid, allowed_mask)) {
d92027a5f30a6c Bing Jiao 2026-01-08 1058 /* Filter out preferred nodes that are not in allowed. */
d92027a5f30a6c Bing Jiao 2026-01-08 1059 nodes_and(preferred, preferred, allowed_mask);
d92027a5f30a6c Bing Jiao 2026-01-08 1060 if (!nodes_empty(preferred)) {
d92027a5f30a6c Bing Jiao 2026-01-08 1061 /* Randomly select one node from preferred. */
d92027a5f30a6c Bing Jiao 2026-01-08 1062 target_nid = node_random(&preferred);
d92027a5f30a6c Bing Jiao 2026-01-08 1063 break;
d92027a5f30a6c Bing Jiao 2026-01-08 1064 }
d92027a5f30a6c Bing Jiao 2026-01-08 1065 /*
d92027a5f30a6c Bing Jiao 2026-01-08 1066 * Preferred nodes in the lower tier are not set in allowed.
d92027a5f30a6c Bing Jiao 2026-01-08 1067 * Recursively get preferred from the next lower tier.
d92027a5f30a6c Bing Jiao 2026-01-08 1068 */
d92027a5f30a6c Bing Jiao 2026-01-08 1069 target_nid = next_demotion_node(target_nid, &preferred);
d92027a5f30a6c Bing Jiao 2026-01-08 1070 }
d92027a5f30a6c Bing Jiao 2026-01-08 1071
d92027a5f30a6c Bing Jiao 2026-01-08 1072 if (target_nid == NUMA_NO_NODE)
d92027a5f30a6c Bing Jiao 2026-01-08 1073 /* Nodes are gone (e.g., hot-unplugged). */
d92027a5f30a6c Bing Jiao 2026-01-08 1074 return 0;
059c4bb2dc3b93 Bing Jiao 2026-01-08 1075 mtc.nid = target_nid;
32008027289239 Jagdish Gediya 2022-08-18 1076
26aa2d199d6f2c Dave Hansen 2021-09-02 1077 /* Demotion ignores all cpuset and mempolicy settings */
29ea04095b9697 SeongJae Park 2025-06-16 1078 migrate_pages(demote_folios, alloc_demote_folio, NULL,
32008027289239 Jagdish Gediya 2022-08-18 1079 (unsigned long)&mtc, MIGRATE_ASYNC, MR_DEMOTION,
26aa2d199d6f2c Dave Hansen 2021-09-02 1080 &nr_succeeded);
26aa2d199d6f2c Dave Hansen 2021-09-02 1081
26aa2d199d6f2c Dave Hansen 2021-09-02 1082 return nr_succeeded;
26aa2d199d6f2c Dave Hansen 2021-09-02 1083 }
26aa2d199d6f2c Dave Hansen 2021-09-02 1084
:::::: The code at line 1046 was first introduced by commit
:::::: 26aa2d199d6f2cfa6f2ef2a5dfe891f2250e71a0 mm/migrate: demote pages during reclaim
:::::: TO: Dave Hansen <dave.hansen@linux.intel.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 2+ messages in thread
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