[akpm-mm:mm-unstable 102/232] mm/mmap.c:1094:9: error: 'area' undeclared
From: kernel test robot
Date: Sun Jul 03 2022 - 23:44:03 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
head: ff9d7221f1fc9bddb4f71f7501154c68b6942b9b
commit: 24a134b0c0a857bbf193eb7b3d8fcbbf77517c5f [102/232] mm: refactor of vma_merge()
config: powerpc-allnoconfig (https://download.01.org/0day-ci/archive/20220704/202207041144.WB9XlrTL-lkp@xxxxxxxxx/config)
compiler: powerpc-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?id=24a134b0c0a857bbf193eb7b3d8fcbbf77517c5f
git remote add akpm-mm https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
git fetch --no-tags akpm-mm mm-unstable
git checkout 24a134b0c0a857bbf193eb7b3d8fcbbf77517c5f
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>
All errors (new ones prefixed by >>):
mm/mmap.c: In function 'vma_merge':
>> mm/mmap.c:1094:9: error: 'area' undeclared (first use in this function)
1094 | area = next;
| ^~~~
mm/mmap.c:1094:9: note: each undeclared identifier is reported only once for each function it appears in
mm/mmap.c:1084:14: warning: unused variable 'merge_next' [-Wunused-variable]
1084 | bool merge_next = false;
| ^~~~~~~~~~
mm/mmap.c:1083:14: warning: unused variable 'merge_prev' [-Wunused-variable]
1083 | bool merge_prev = false;
| ^~~~~~~~~~
mm/mmap.c:1081:45: warning: unused variable 'res' [-Wunused-variable]
1081 | struct vm_area_struct *mid, *next, *res;
| ^~~
mm/mmap.c:1081:32: warning: unused variable 'mid' [-Wunused-variable]
1081 | struct vm_area_struct *mid, *next, *res;
| ^~~
vim +/area +1094 mm/mmap.c
^1da177e4c3f41 Linus Torvalds 2005-04-16 1028
^1da177e4c3f41 Linus Torvalds 2005-04-16 1029 /*
9a10064f5625d5 Colin Cross 2022-01-14 1030 * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name),
9a10064f5625d5 Colin Cross 2022-01-14 1031 * figure out whether that can be merged with its predecessor or its
9a10064f5625d5 Colin Cross 2022-01-14 1032 * successor. Or both (it neatly fills a hole).
^1da177e4c3f41 Linus Torvalds 2005-04-16 1033 *
^1da177e4c3f41 Linus Torvalds 2005-04-16 1034 * In most cases - when called for mmap, brk or mremap - [addr,end) is
^1da177e4c3f41 Linus Torvalds 2005-04-16 1035 * certain not to be mapped by the time vma_merge is called; but when
^1da177e4c3f41 Linus Torvalds 2005-04-16 1036 * called for mprotect, it is certain to be already mapped (either at
^1da177e4c3f41 Linus Torvalds 2005-04-16 1037 * an offset within prev, or at the start of next), and the flags of
^1da177e4c3f41 Linus Torvalds 2005-04-16 1038 * this area are about to be changed to vm_flags - and the no-change
^1da177e4c3f41 Linus Torvalds 2005-04-16 1039 * case has already been eliminated.
^1da177e4c3f41 Linus Torvalds 2005-04-16 1040 *
^1da177e4c3f41 Linus Torvalds 2005-04-16 1041 * The following mprotect cases have to be considered, where AAAA is
^1da177e4c3f41 Linus Torvalds 2005-04-16 1042 * the area passed down from mprotect_fixup, never extending beyond one
^1da177e4c3f41 Linus Torvalds 2005-04-16 1043 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
^1da177e4c3f41 Linus Torvalds 2005-04-16 1044 *
5d42ab293f5181 Wei Yang 2019-11-30 1045 * AAAA AAAA AAAA
5d42ab293f5181 Wei Yang 2019-11-30 1046 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN
5d42ab293f5181 Wei Yang 2019-11-30 1047 * cannot merge might become might become
5d42ab293f5181 Wei Yang 2019-11-30 1048 * PPNNNNNNNNNN PPPPPPPPPPNN
5d42ab293f5181 Wei Yang 2019-11-30 1049 * mmap, brk or case 4 below case 5 below
5d42ab293f5181 Wei Yang 2019-11-30 1050 * mremap move:
5d42ab293f5181 Wei Yang 2019-11-30 1051 * AAAA AAAA
5d42ab293f5181 Wei Yang 2019-11-30 1052 * PPPP NNNN PPPPNNNNXXXX
5d42ab293f5181 Wei Yang 2019-11-30 1053 * might become might become
5d42ab293f5181 Wei Yang 2019-11-30 1054 * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or
5d42ab293f5181 Wei Yang 2019-11-30 1055 * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or
5d42ab293f5181 Wei Yang 2019-11-30 1056 * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8
^1da177e4c3f41 Linus Torvalds 2005-04-16 1057 *
8bb4e7a2ee26c0 Wei Yang 2019-03-05 1058 * It is important for case 8 that the vma NNNN overlapping the
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1059 * region AAAA is never going to extended over XXXX. Instead XXXX must
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1060 * be extended in region AAAA and NNNN must be removed. This way in
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1061 * all cases where vma_merge succeeds, the moment vma_adjust drops the
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1062 * rmap_locks, the properties of the merged vma will be already
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1063 * correct for the whole merged range. Some of those properties like
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1064 * vm_page_prot/vm_flags may be accessed by rmap_walks and they must
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1065 * be correct for the whole merged range immediately after the
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1066 * rmap_locks are released. Otherwise if XXXX would be removed and
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1067 * NNNN would be extended over the XXXX range, remove_migration_ptes
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1068 * or other rmap walkers (if working on addresses beyond the "end"
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1069 * parameter) may establish ptes with the wrong permissions of NNNN
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1070 * instead of the right permissions of XXXX.
^1da177e4c3f41 Linus Torvalds 2005-04-16 1071 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 1072 struct vm_area_struct *vma_merge(struct mm_struct *mm,
^1da177e4c3f41 Linus Torvalds 2005-04-16 1073 struct vm_area_struct *prev, unsigned long addr,
^1da177e4c3f41 Linus Torvalds 2005-04-16 1074 unsigned long end, unsigned long vm_flags,
^1da177e4c3f41 Linus Torvalds 2005-04-16 1075 struct anon_vma *anon_vma, struct file *file,
19a809afe2fe08 Andrea Arcangeli 2015-09-04 1076 pgoff_t pgoff, struct mempolicy *policy,
9a10064f5625d5 Colin Cross 2022-01-14 1077 struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
5c26f6ac9416b6 Suren Baghdasaryan 2022-03-04 1078 struct anon_vma_name *anon_name)
^1da177e4c3f41 Linus Torvalds 2005-04-16 1079 {
^1da177e4c3f41 Linus Torvalds 2005-04-16 1080 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
24a134b0c0a857 Jakub Matěna 2022-06-03 1081 struct vm_area_struct *mid, *next, *res;
24a134b0c0a857 Jakub Matěna 2022-06-03 1082 int err = -1;
24a134b0c0a857 Jakub Matěna 2022-06-03 1083 bool merge_prev = false;
24a134b0c0a857 Jakub Matěna 2022-06-03 1084 bool merge_next = false;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1085
^1da177e4c3f41 Linus Torvalds 2005-04-16 1086 /*
^1da177e4c3f41 Linus Torvalds 2005-04-16 1087 * We later require that vma->vm_flags == vm_flags,
^1da177e4c3f41 Linus Torvalds 2005-04-16 1088 * so this tests vma->vm_flags & VM_SPECIAL, too.
^1da177e4c3f41 Linus Torvalds 2005-04-16 1089 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 1090 if (vm_flags & VM_SPECIAL)
^1da177e4c3f41 Linus Torvalds 2005-04-16 1091 return NULL;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1092
584b4cb00d55ac Liam R. Howlett 2022-06-21 1093 next = find_vma(mm, prev ? prev->vm_end : 0);
^1da177e4c3f41 Linus Torvalds 2005-04-16 @1094 area = next;
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1095 if (area && area->vm_end == end) /* cases 6, 7, 8 */
584b4cb00d55ac Liam R. Howlett 2022-06-21 1096 next = find_vma(mm, next->vm_end);
^1da177e4c3f41 Linus Torvalds 2005-04-16 1097
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1098 /* verify some invariant that must be enforced by the caller */
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1099 VM_WARN_ON(prev && addr <= prev->vm_start);
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1100 VM_WARN_ON(area && end > area->vm_end);
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1101 VM_WARN_ON(addr >= end);
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1102
^1da177e4c3f41 Linus Torvalds 2005-04-16 1103 /*
^1da177e4c3f41 Linus Torvalds 2005-04-16 1104 * Can it merge with the predecessor?
^1da177e4c3f41 Linus Torvalds 2005-04-16 1105 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 1106 if (prev && prev->vm_end == addr &&
^1da177e4c3f41 Linus Torvalds 2005-04-16 1107 mpol_equal(vma_policy(prev), policy) &&
^1da177e4c3f41 Linus Torvalds 2005-04-16 1108 can_vma_merge_after(prev, vm_flags,
19a809afe2fe08 Andrea Arcangeli 2015-09-04 1109 anon_vma, file, pgoff,
9a10064f5625d5 Colin Cross 2022-01-14 1110 vm_userfaultfd_ctx, anon_name)) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 1111 /*
^1da177e4c3f41 Linus Torvalds 2005-04-16 1112 * OK, it can. Can we now merge in the successor as well?
^1da177e4c3f41 Linus Torvalds 2005-04-16 1113 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 1114 if (next && end == next->vm_start &&
^1da177e4c3f41 Linus Torvalds 2005-04-16 1115 mpol_equal(policy, vma_policy(next)) &&
^1da177e4c3f41 Linus Torvalds 2005-04-16 1116 can_vma_merge_before(next, vm_flags,
19a809afe2fe08 Andrea Arcangeli 2015-09-04 1117 anon_vma, file,
19a809afe2fe08 Andrea Arcangeli 2015-09-04 1118 pgoff+pglen,
9a10064f5625d5 Colin Cross 2022-01-14 1119 vm_userfaultfd_ctx, anon_name) &&
^1da177e4c3f41 Linus Torvalds 2005-04-16 1120 is_mergeable_anon_vma(prev->anon_vma,
965f55dea0e331 Shaohua Li 2011-05-24 1121 next->anon_vma, NULL)) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 1122 /* cases 1, 6 */
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1123 err = __vma_adjust(prev, prev->vm_start,
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1124 next->vm_end, prev->vm_pgoff, NULL,
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1125 prev);
^1da177e4c3f41 Linus Torvalds 2005-04-16 1126 } else /* cases 2, 5, 7 */
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1127 err = __vma_adjust(prev, prev->vm_start,
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1128 end, prev->vm_pgoff, NULL, prev);
5beb49305251e5 Rik van Riel 2010-03-05 1129 if (err)
5beb49305251e5 Rik van Riel 2010-03-05 1130 return NULL;
c791576c60288c Yang Shi 2022-05-19 1131 khugepaged_enter_vma(prev, vm_flags);
^1da177e4c3f41 Linus Torvalds 2005-04-16 1132 return prev;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1133 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 1134
^1da177e4c3f41 Linus Torvalds 2005-04-16 1135 /*
^1da177e4c3f41 Linus Torvalds 2005-04-16 1136 * Can this new request be merged in front of next?
^1da177e4c3f41 Linus Torvalds 2005-04-16 1137 */
^1da177e4c3f41 Linus Torvalds 2005-04-16 1138 if (next && end == next->vm_start &&
^1da177e4c3f41 Linus Torvalds 2005-04-16 1139 mpol_equal(policy, vma_policy(next)) &&
^1da177e4c3f41 Linus Torvalds 2005-04-16 1140 can_vma_merge_before(next, vm_flags,
19a809afe2fe08 Andrea Arcangeli 2015-09-04 1141 anon_vma, file, pgoff+pglen,
9a10064f5625d5 Colin Cross 2022-01-14 1142 vm_userfaultfd_ctx, anon_name)) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 1143 if (prev && addr < prev->vm_end) /* case 4 */
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1144 err = __vma_adjust(prev, prev->vm_start,
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1145 addr, prev->vm_pgoff, NULL, next);
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1146 else { /* cases 3, 8 */
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1147 err = __vma_adjust(area, addr, next->vm_end,
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1148 next->vm_pgoff - pglen, NULL, next);
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1149 /*
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1150 * In case 3 area is already equal to next and
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1151 * this is a noop, but in case 8 "area" has
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1152 * been removed and next was expanded over it.
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1153 */
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1154 area = next;
e86f15ee64d8ee Andrea Arcangeli 2016-10-07 1155 }
5beb49305251e5 Rik van Riel 2010-03-05 1156 if (err)
5beb49305251e5 Rik van Riel 2010-03-05 1157 return NULL;
c791576c60288c Yang Shi 2022-05-19 1158 khugepaged_enter_vma(area, vm_flags);
^1da177e4c3f41 Linus Torvalds 2005-04-16 1159 return area;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1160 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 1161
^1da177e4c3f41 Linus Torvalds 2005-04-16 1162 return NULL;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1163 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 1164
:::::: The code at line 1094 was first introduced by commit
:::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2
:::::: TO: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx>
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