tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: e7d6987e09a328d4a949701db40ef63fbb970670 commit: 70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5 [5085/5845] mm: teach core mm about pte markers config: x86_64-randconfig-a002-20210928 (https://download.01.org/0day-ci/archive/20220424/202204240320.TGDuGcsL-lkp@xxxxxxxxx/config) compiler: gcc-11 (Debian 11.2.0-20) 11.2.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5 git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5 # save the config file mkdir build_dir && cp config build_dir/.config make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> Note: the linux-next/master HEAD e7d6987e09a328d4a949701db40ef63fbb970670 builds fine. It may have been fixed somewhere. All errors (new ones prefixed by >>): fs/userfaultfd.c: In function 'userfaultfd_must_wait': >> fs/userfaultfd.c:337:13: error: implicit declaration of function 'pte_none_mostly' [-Werror=implicit-function-declaration] 337 | if (pte_none_mostly(*pte)) | ^~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +/pte_none_mostly +337 fs/userfaultfd.c 272 273 /* 274 * Verify the pagetables are still not ok after having reigstered into 275 * the fault_pending_wqh to avoid userland having to UFFDIO_WAKE any 276 * userfault that has already been resolved, if userfaultfd_read and 277 * UFFDIO_COPY|ZEROPAGE are being run simultaneously on two different 278 * threads. 279 */ 280 static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx, 281 unsigned long address, 282 unsigned long flags, 283 unsigned long reason) 284 { 285 struct mm_struct *mm = ctx->mm; 286 pgd_t *pgd; 287 p4d_t *p4d; 288 pud_t *pud; 289 pmd_t *pmd, _pmd; 290 pte_t *pte; 291 bool ret = true; 292 293 mmap_assert_locked(mm); 294 295 pgd = pgd_offset(mm, address); 296 if (!pgd_present(*pgd)) 297 goto out; 298 p4d = p4d_offset(pgd, address); 299 if (!p4d_present(*p4d)) 300 goto out; 301 pud = pud_offset(p4d, address); 302 if (!pud_present(*pud)) 303 goto out; 304 pmd = pmd_offset(pud, address); 305 /* 306 * READ_ONCE must function as a barrier with narrower scope 307 * and it must be equivalent to: 308 * _pmd = *pmd; barrier(); 309 * 310 * This is to deal with the instability (as in 311 * pmd_trans_unstable) of the pmd. 312 */ 313 _pmd = READ_ONCE(*pmd); 314 if (pmd_none(_pmd)) 315 goto out; 316 317 ret = false; 318 if (!pmd_present(_pmd)) 319 goto out; 320 321 if (pmd_trans_huge(_pmd)) { 322 if (!pmd_write(_pmd) && (reason & VM_UFFD_WP)) 323 ret = true; 324 goto out; 325 } 326 327 /* 328 * the pmd is stable (as in !pmd_trans_unstable) so we can re-read it 329 * and use the standard pte_offset_map() instead of parsing _pmd. 330 */ 331 pte = pte_offset_map(pmd, address); 332 /* 333 * Lockless access: we're in a wait_event so it's ok if it 334 * changes under us. PTE markers should be handled the same as none 335 * ptes here. 336 */ > 337 if (pte_none_mostly(*pte)) 338 ret = true; 339 if (!pte_write(*pte) && (reason & VM_UFFD_WP)) 340 ret = true; 341 pte_unmap(pte); 342 343 out: 344 return ret; 345 } 346 -- 0-DAY CI Kernel Test Service https://01.org/lkp
