* Dan Carpenter <dan.carpenter@xxxxxxxxxx> [240910 09:37]: > Hi Xiao, > > kernel test robot noticed the following build warnings: > > url: https://github.com/intel-lab-lkp/linux/commits/Xiao-Yang/mm-vma-Return-the-exact-errno-for-__split_vma-and-mas_store_gfp/20240909-130325 > base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything > patch link: https://lore.kernel.org/r/20240909050226.2053-1-ice_yangxiao%40163.com > patch subject: [PATCH] mm/vma: Return the exact errno for __split_vma() and mas_store_gfp() > config: x86_64-randconfig-161-20240910 (https://download.01.org/0day-ci/archive/20240910/202409102026.LOh8J1Lh-lkp@xxxxxxxxx/config) > compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1) > > 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> > | Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > | Closes: https://lore.kernel.org/r/202409102026.LOh8J1Lh-lkp@xxxxxxxxx/ > > smatch warnings: > mm/vma.c:1263 vms_gather_munmap_vmas() warn: missing error code 'error' > > vim +/error +1263 mm/vma.c > > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1166 /* > dba14840905f9e Liam R. Howlett 2024-08-30 1167 * vms_gather_munmap_vmas() - Put all VMAs within a range into a maple tree > 6898c9039bc8e3 Liam R. Howlett 2024-08-30 1168 * for removal at a later date. Handles splitting first and last if necessary > 6898c9039bc8e3 Liam R. Howlett 2024-08-30 1169 * and marking the vmas as isolated. > 6898c9039bc8e3 Liam R. Howlett 2024-08-30 1170 * > dba14840905f9e Liam R. Howlett 2024-08-30 1171 * @vms: The vma munmap struct > 6898c9039bc8e3 Liam R. Howlett 2024-08-30 1172 * @mas_detach: The maple state tracking the detached tree > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1173 * > 6898c9039bc8e3 Liam R. Howlett 2024-08-30 1174 * Return: 0 on success, -EPERM on mseal vmas, -ENOMEM otherwise > > This comment needs to be updated. > > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1175 */ > 9014b230d88d7f Liam R. Howlett 2024-08-30 1176 int vms_gather_munmap_vmas(struct vma_munmap_struct *vms, > dba14840905f9e Liam R. Howlett 2024-08-30 1177 struct ma_state *mas_detach) > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1178 { > 01cf21e9e11957 Liam R. Howlett 2024-08-30 1179 struct vm_area_struct *next = NULL; > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1180 int error = -ENOMEM; > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1181 > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1182 /* > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1183 * If we need to split any vma, do it now to save pain later. > 20831cd6f814ea Liam R. Howlett 2024-08-30 1184 * Does it split the first one? > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1185 */ > dba14840905f9e Liam R. Howlett 2024-08-30 1186 if (vms->start > vms->vma->vm_start) { > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1187 > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1188 /* > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1189 * Make sure that map_count on return from munmap() will > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1190 * not exceed its limit; but let map_count go just above > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1191 * its limit temporarily, to help free resources as expected. > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1192 */ > dba14840905f9e Liam R. Howlett 2024-08-30 1193 if (vms->end < vms->vma->vm_end && > 63fc66f5b6b18f Liam R. Howlett 2024-08-30 1194 vms->vma->vm_mm->map_count >= sysctl_max_map_count) > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1195 goto map_count_exceeded; > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1196 > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1197 /* Don't bother splitting the VMA if we can't unmap it anyway */ > dba14840905f9e Liam R. Howlett 2024-08-30 1198 if (!can_modify_vma(vms->vma)) { > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1199 error = -EPERM; > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1200 goto start_split_failed; > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1201 } > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1202 > 013545e1b9bca0 Xiao Yang 2024-09-09 1203 error = __split_vma(vms->vmi, vms->vma, vms->start, 1); > 013545e1b9bca0 Xiao Yang 2024-09-09 1204 if (error) > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1205 goto start_split_failed; > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1206 } > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1207 vms->prev = vma_prev(vms->vmi); > 9c3ebeda8fb5a8 Liam R. Howlett 2024-08-30 1208 if (vms->prev) > 9c3ebeda8fb5a8 Liam R. Howlett 2024-08-30 1209 vms->unmap_start = vms->prev->vm_end; > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1210 > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1211 /* > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1212 * Detach a range of VMAs from the mm. Using next as a temp variable as > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1213 * it is always overwritten. > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1214 */ > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1215 for_each_vma_range(*(vms->vmi), next, vms->end) { > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1216 long nrpages; > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1217 > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1218 if (!can_modify_vma(next)) { > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1219 error = -EPERM; > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1220 goto modify_vma_failed; > df2a7df9a9aa32 Pedro Falcato 2024-08-17 1221 } > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1222 /* Does it split the end? */ > dba14840905f9e Liam R. Howlett 2024-08-30 1223 if (next->vm_end > vms->end) { > 013545e1b9bca0 Xiao Yang 2024-09-09 1224 error = __split_vma(vms->vmi, next, vms->end, 0); > 013545e1b9bca0 Xiao Yang 2024-09-09 1225 if (error) > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1226 goto end_split_failed; > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1227 } > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1228 vma_start_write(next); > dba14840905f9e Liam R. Howlett 2024-08-30 1229 mas_set(mas_detach, vms->vma_count++); > 013545e1b9bca0 Xiao Yang 2024-09-09 1230 error = mas_store_gfp(mas_detach, next, GFP_KERNEL); > 013545e1b9bca0 Xiao Yang 2024-09-09 1231 if (error) > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1232 goto munmap_gather_failed; > 6898c9039bc8e3 Liam R. Howlett 2024-08-30 1233 > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1234 vma_mark_detached(next, true); > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1235 nrpages = vma_pages(next); > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1236 > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1237 vms->nr_pages += nrpages; > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1238 if (next->vm_flags & VM_LOCKED) > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1239 vms->locked_vm += nrpages; > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1240 > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1241 if (next->vm_flags & VM_ACCOUNT) > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1242 vms->nr_accounted += nrpages; > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1243 > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1244 if (is_exec_mapping(next->vm_flags)) > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1245 vms->exec_vm += nrpages; > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1246 else if (is_stack_mapping(next->vm_flags)) > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1247 vms->stack_vm += nrpages; > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1248 else if (is_data_mapping(next->vm_flags)) > 17f1ae9b40c6b0 Liam R. Howlett 2024-08-30 1249 vms->data_vm += nrpages; > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1250 > dba14840905f9e Liam R. Howlett 2024-08-30 1251 if (unlikely(vms->uf)) { > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1252 /* > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1253 * If userfaultfd_unmap_prep returns an error the vmas > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1254 * will remain split, but userland will get a > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1255 * highly unexpected error anyway. This is no > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1256 * different than the case where the first of the two > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1257 * __split_vma fails, but we don't undo the first > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1258 * split, despite we could. This is unlikely enough > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1259 * failure that it's not worth optimizing it for. > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 1260 */ > dba14840905f9e Liam R. Howlett 2024-08-30 1261 if (userfaultfd_unmap_prep(next, vms->start, vms->end, > dba14840905f9e Liam R. Howlett 2024-08-30 1262 vms->uf)) > 49b1b8d6f68310 Lorenzo Stoakes 2024-07-29 @1263 goto userfaultfd_error; > > Needs an "error = -ENOMEM;" here. I haven't reviewed this function outside of > what the zero day bot puts into this email. Thanks Dan. This is already addressed in v2 [1]. [1]. https://lore.kernel.org/all/20240909125621.1994-1-ice_yangxiao@xxxxxxx/ Regards, Liam ...
