| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <202202141933.YLNzdo4f-lkp@intel.com>
Date: Mon, 14 Feb 2022 19:53:39 +0800
From: kernel test robot <lkp@...el.com>
To: "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc: kbuild-all@...ts.01.org, linux-kernel@...r.kernel.org
Subject: [willy-pagecache:for-next 52/85] mm/page_vma_mapped.c:246
page_vma_mapped_walk() warn: always true condition '(pvmw->nr_pages >= (1 <<
( - 12))) => (0-u32max >= 0)'
tree: git://git.infradead.org/users/willy/pagecache for-next
head: c267b33d0001488f1d9dad12d6a87655e174d914
commit: 9733dd1f11d6b6f8a38fa82f0cc014f7840cbd67 [52/85] mm: Convert page_vma_mapped_walk to work on PFNs
config: xtensa-randconfig-m031-20220213 (https://download.01.org/0day-ci/archive/20220214/202202141933.YLNzdo4f-lkp@intel.com/config)
compiler: xtensa-linux-gcc (GCC) 11.2.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>
smatch warnings:
mm/page_vma_mapped.c:246 page_vma_mapped_walk() warn: always true condition '(pvmw->nr_pages >= (1 << ( - 12))) => (0-u32max >= 0)'
vim +246 mm/page_vma_mapped.c
126
127 /**
128 * page_vma_mapped_walk - check if @pvmw->pfn is mapped in @pvmw->vma at
129 * @pvmw->address
130 * @pvmw: pointer to struct page_vma_mapped_walk. page, vma, address and flags
131 * must be set. pmd, pte and ptl must be NULL.
132 *
133 * Returns true if the page is mapped in the vma. @pvmw->pmd and @pvmw->pte point
134 * to relevant page table entries. @pvmw->ptl is locked. @pvmw->address is
135 * adjusted if needed (for PTE-mapped THPs).
136 *
137 * If @pvmw->pmd is set but @pvmw->pte is not, you have found PMD-mapped page
138 * (usually THP). For PTE-mapped THP, you should run page_vma_mapped_walk() in
139 * a loop to find all PTEs that map the THP.
140 *
141 * For HugeTLB pages, @pvmw->pte is set to the relevant page table entry
142 * regardless of which page table level the page is mapped at. @pvmw->pmd is
143 * NULL.
144 *
145 * Returns false if there are no more page table entries for the page in
146 * the vma. @pvmw->ptl is unlocked and @pvmw->pte is unmapped.
147 *
148 * If you need to stop the walk before page_vma_mapped_walk() returned false,
149 * use page_vma_mapped_walk_done(). It will do the housekeeping.
150 */
151 bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
152 {
153 struct vm_area_struct *vma = pvmw->vma;
154 struct mm_struct *mm = vma->vm_mm;
155 unsigned long end;
156 pgd_t *pgd;
157 p4d_t *p4d;
158 pud_t *pud;
159 pmd_t pmde;
160
161 /* The only possible pmd mapping has been handled on last iteration */
162 if (pvmw->pmd && !pvmw->pte)
163 return not_found(pvmw);
164
165 if (unlikely(is_vm_hugetlb_page(vma))) {
166 unsigned long size = pvmw->nr_pages * PAGE_SIZE;
167 /* The only possible mapping was handled on last iteration */
168 if (pvmw->pte)
169 return not_found(pvmw);
170
171 /* when pud is not present, pte will be NULL */
172 pvmw->pte = huge_pte_offset(mm, pvmw->address, size);
173 if (!pvmw->pte)
174 return false;
175
176 pvmw->ptl = huge_pte_lockptr(size_to_hstate(size), mm,
177 pvmw->pte);
178 spin_lock(pvmw->ptl);
179 if (!check_pte(pvmw))
180 return not_found(pvmw);
181 return true;
182 }
183
184 end = vma_address_end(pvmw);
185 if (pvmw->pte)
186 goto next_pte;
187 restart:
188 do {
189 pgd = pgd_offset(mm, pvmw->address);
190 if (!pgd_present(*pgd)) {
191 step_forward(pvmw, PGDIR_SIZE);
192 continue;
193 }
194 p4d = p4d_offset(pgd, pvmw->address);
195 if (!p4d_present(*p4d)) {
196 step_forward(pvmw, P4D_SIZE);
197 continue;
198 }
199 pud = pud_offset(p4d, pvmw->address);
200 if (!pud_present(*pud)) {
201 step_forward(pvmw, PUD_SIZE);
202 continue;
203 }
204
205 pvmw->pmd = pmd_offset(pud, pvmw->address);
206 /*
207 * Make sure the pmd value isn't cached in a register by the
208 * compiler and used as a stale value after we've observed a
209 * subsequent update.
210 */
211 pmde = READ_ONCE(*pvmw->pmd);
212
213 if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) {
214 pvmw->ptl = pmd_lock(mm, pvmw->pmd);
215 pmde = *pvmw->pmd;
216 if (likely(pmd_trans_huge(pmde))) {
217 if (pvmw->flags & PVMW_MIGRATION)
218 return not_found(pvmw);
219 if (!check_pmd(pmd_pfn(pmde), pvmw))
220 return not_found(pvmw);
221 return true;
222 }
223 if (!pmd_present(pmde)) {
224 swp_entry_t entry;
225
226 if (!thp_migration_supported() ||
227 !(pvmw->flags & PVMW_MIGRATION))
228 return not_found(pvmw);
229 entry = pmd_to_swp_entry(pmde);
230 if (!is_migration_entry(entry) ||
231 !check_pmd(swp_offset(entry), pvmw))
232 return not_found(pvmw);
233 return true;
234 }
235 /* THP pmd was split under us: handle on pte level */
236 spin_unlock(pvmw->ptl);
237 pvmw->ptl = NULL;
238 } else if (!pmd_present(pmde)) {
239 /*
240 * If PVMW_SYNC, take and drop THP pmd lock so that we
241 * cannot return prematurely, while zap_huge_pmd() has
242 * cleared *pmd but not decremented compound_mapcount().
243 */
244 if ((pvmw->flags & PVMW_SYNC) &&
245 transparent_hugepage_active(vma) &&
> 246 (pvmw->nr_pages >= HPAGE_PMD_NR)) {
247 spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
248
249 spin_unlock(ptl);
250 }
251 step_forward(pvmw, PMD_SIZE);
252 continue;
253 }
254 if (!map_pte(pvmw))
255 goto next_pte;
256 this_pte:
257 if (check_pte(pvmw))
258 return true;
259 next_pte:
260 do {
261 pvmw->address += PAGE_SIZE;
262 if (pvmw->address >= end)
263 return not_found(pvmw);
264 /* Did we cross page table boundary? */
265 if ((pvmw->address & (PMD_SIZE - PAGE_SIZE)) == 0) {
266 if (pvmw->ptl) {
267 spin_unlock(pvmw->ptl);
268 pvmw->ptl = NULL;
269 }
270 pte_unmap(pvmw->pte);
271 pvmw->pte = NULL;
272 goto restart;
273 }
274 pvmw->pte++;
275 if ((pvmw->flags & PVMW_SYNC) && !pvmw->ptl) {
276 pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
277 spin_lock(pvmw->ptl);
278 }
279 } while (pte_none(*pvmw->pte));
280
281 if (!pvmw->ptl) {
282 pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
283 spin_lock(pvmw->ptl);
284 }
285 goto this_pte;
286 } while (pvmw->address < end);
287
288 return false;
289 }
290
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Powered by blists - more mailing lists