tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable head: 7b6c5895bb9ac3aadddd51108b7bb3bb1c7f3110 commit: 3129f7896afb86e411c0b59a553fbb4053db4012 [400/415] mm/mremap: initial refactor of move_vma() config: i386-buildonly-randconfig-004-20250305 (https://download.01.org/0day-ci/archive/20250305/202503051356.jJQQ0DoR-lkp@xxxxxxxxx/config) compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250305/202503051356.jJQQ0DoR-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/202503051356.jJQQ0DoR-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): In file included from mm/mremap.c:11: In file included from include/linux/mm.h:2321: include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion] 518 | return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_" | ~~~~~~~~~~~ ^ ~~~ In file included from mm/mremap.c:12: include/linux/mm_inline.h:47:41: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion] 47 | __mod_lruvec_state(lruvec, NR_LRU_BASE + lru, nr_pages); | ~~~~~~~~~~~ ^ ~~~ include/linux/mm_inline.h:49:22: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum lru_list') [-Wenum-enum-conversion] 49 | NR_ZONE_LRU_BASE + lru, nr_pages); | ~~~~~~~~~~~~~~~~ ^ ~~~ >> mm/mremap.c:908:7: warning: variable 'err' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 908 | if (vma->vm_start != old_addr) | ^~~~~~~~~~~~~~~~~~~~~~~~~ mm/mremap.c:910:8: note: uninitialized use occurs here 910 | if (!err && vma->vm_end != old_addr + old_len) | ^~~ mm/mremap.c:908:3: note: remove the 'if' if its condition is always true 908 | if (vma->vm_start != old_addr) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 909 | err = vma->vm_ops->may_split(vma, old_addr); mm/mremap.c:895:19: note: initialize the variable 'err' to silence this warning 895 | unsigned long err; | ^ | = 0 4 warnings generated. vim +908 mm/mremap.c 3129f7896afb86 Lorenzo Stoakes 2025-03-03 887 3129f7896afb86 Lorenzo Stoakes 2025-03-03 888 /* 3129f7896afb86 Lorenzo Stoakes 2025-03-03 889 * Perform checks before attempting to write a VMA prior to it being 3129f7896afb86 Lorenzo Stoakes 2025-03-03 890 * moved. 3129f7896afb86 Lorenzo Stoakes 2025-03-03 891 */ 3129f7896afb86 Lorenzo Stoakes 2025-03-03 892 static unsigned long prep_move_vma(struct vma_remap_struct *vrm, 3129f7896afb86 Lorenzo Stoakes 2025-03-03 893 unsigned long *vm_flags_ptr) 3129f7896afb86 Lorenzo Stoakes 2025-03-03 894 { 3129f7896afb86 Lorenzo Stoakes 2025-03-03 895 unsigned long err; 3129f7896afb86 Lorenzo Stoakes 2025-03-03 896 struct vm_area_struct *vma = vrm->vma; 3129f7896afb86 Lorenzo Stoakes 2025-03-03 897 unsigned long old_addr = vrm->addr; 3129f7896afb86 Lorenzo Stoakes 2025-03-03 898 unsigned long old_len = vrm->old_len; ^1da177e4c3f41 Linus Torvalds 2005-04-16 899 ^1da177e4c3f41 Linus Torvalds 2005-04-16 900 /* ^1da177e4c3f41 Linus Torvalds 2005-04-16 901 * We'd prefer to avoid failure later on in do_munmap: ^1da177e4c3f41 Linus Torvalds 2005-04-16 902 * which may split one vma into three before unmapping. ^1da177e4c3f41 Linus Torvalds 2005-04-16 903 */ 3129f7896afb86 Lorenzo Stoakes 2025-03-03 904 if (current->mm->map_count >= sysctl_max_map_count - 3) ^1da177e4c3f41 Linus Torvalds 2005-04-16 905 return -ENOMEM; ^1da177e4c3f41 Linus Torvalds 2005-04-16 906 73d5e06299195f Dmitry Safonov 2020-12-14 907 if (vma->vm_ops && vma->vm_ops->may_split) { 73d5e06299195f Dmitry Safonov 2020-12-14 @908 if (vma->vm_start != old_addr) 73d5e06299195f Dmitry Safonov 2020-12-14 909 err = vma->vm_ops->may_split(vma, old_addr); 73d5e06299195f Dmitry Safonov 2020-12-14 910 if (!err && vma->vm_end != old_addr + old_len) 73d5e06299195f Dmitry Safonov 2020-12-14 911 err = vma->vm_ops->may_split(vma, old_addr + old_len); 73d5e06299195f Dmitry Safonov 2020-12-14 912 if (err) 73d5e06299195f Dmitry Safonov 2020-12-14 913 return err; 73d5e06299195f Dmitry Safonov 2020-12-14 914 } 73d5e06299195f Dmitry Safonov 2020-12-14 915 1ff82995731667 Hugh Dickins 2009-09-21 916 /* 1ff82995731667 Hugh Dickins 2009-09-21 917 * Advise KSM to break any KSM pages in the area to be moved: 1ff82995731667 Hugh Dickins 2009-09-21 918 * it would be confusing if they were to turn up at the new 1ff82995731667 Hugh Dickins 2009-09-21 919 * location, where they happen to coincide with different KSM 1ff82995731667 Hugh Dickins 2009-09-21 920 * pages recently unmapped. But leave vma->vm_flags as it was, 1ff82995731667 Hugh Dickins 2009-09-21 921 * so KSM can come around to merge on vma and new_vma afterwards. 1ff82995731667 Hugh Dickins 2009-09-21 922 */ 7103ad323b1ae3 Hugh Dickins 2009-09-21 923 err = ksm_madvise(vma, old_addr, old_addr + old_len, 3129f7896afb86 Lorenzo Stoakes 2025-03-03 924 MADV_UNMERGEABLE, vm_flags_ptr); 7103ad323b1ae3 Hugh Dickins 2009-09-21 925 if (err) 7103ad323b1ae3 Hugh Dickins 2009-09-21 926 return err; 1ff82995731667 Hugh Dickins 2009-09-21 927 3129f7896afb86 Lorenzo Stoakes 2025-03-03 928 return 0; ad8ee77ea9db1f Dmitry Safonov 2020-12-14 929 } ad8ee77ea9db1f Dmitry Safonov 2020-12-14 930 :::::: The code at line 908 was first introduced by commit :::::: 73d5e06299195f4df82832cfc4a3a0c574c1e473 mremap: check if it's possible to split original vma :::::: TO: Dmitry Safonov <dima@xxxxxxxxxx> :::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
