diff options
Diffstat (limited to 'mm')
-rw-r--r-- | mm/rmap.c | 30 |
1 files changed, 29 insertions, 1 deletions
@@ -1131,6 +1131,20 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount, | |||
1131 | return ret; | 1131 | return ret; |
1132 | } | 1132 | } |
1133 | 1133 | ||
1134 | static bool is_vma_temporary_stack(struct vm_area_struct *vma) | ||
1135 | { | ||
1136 | int maybe_stack = vma->vm_flags & (VM_GROWSDOWN | VM_GROWSUP); | ||
1137 | |||
1138 | if (!maybe_stack) | ||
1139 | return false; | ||
1140 | |||
1141 | if ((vma->vm_flags & VM_STACK_INCOMPLETE_SETUP) == | ||
1142 | VM_STACK_INCOMPLETE_SETUP) | ||
1143 | return true; | ||
1144 | |||
1145 | return false; | ||
1146 | } | ||
1147 | |||
1134 | /** | 1148 | /** |
1135 | * try_to_unmap_anon - unmap or unlock anonymous page using the object-based | 1149 | * try_to_unmap_anon - unmap or unlock anonymous page using the object-based |
1136 | * rmap method | 1150 | * rmap method |
@@ -1159,7 +1173,21 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags) | |||
1159 | 1173 | ||
1160 | list_for_each_entry(avc, &anon_vma->head, same_anon_vma) { | 1174 | list_for_each_entry(avc, &anon_vma->head, same_anon_vma) { |
1161 | struct vm_area_struct *vma = avc->vma; | 1175 | struct vm_area_struct *vma = avc->vma; |
1162 | unsigned long address = vma_address(page, vma); | 1176 | unsigned long address; |
1177 | |||
1178 | /* | ||
1179 | * During exec, a temporary VMA is setup and later moved. | ||
1180 | * The VMA is moved under the anon_vma lock but not the | ||
1181 | * page tables leading to a race where migration cannot | ||
1182 | * find the migration ptes. Rather than increasing the | ||
1183 | * locking requirements of exec(), migration skips | ||
1184 | * temporary VMAs until after exec() completes. | ||
1185 | */ | ||
1186 | if (PAGE_MIGRATION && (flags & TTU_MIGRATION) && | ||
1187 | is_vma_temporary_stack(vma)) | ||
1188 | continue; | ||
1189 | |||
1190 | address = vma_address(page, vma); | ||
1163 | if (address == -EFAULT) | 1191 | if (address == -EFAULT) |
1164 | continue; | 1192 | continue; |
1165 | ret = try_to_unmap_one(page, vma, address, flags); | 1193 | ret = try_to_unmap_one(page, vma, address, flags); |