[ammarfaizi2-block:google/android/kernel/common/android12-5.4 6517/9999] fs/userfaultfd.c:1519:9: warning: variable 'ioctls_out' set but not used
From: kernel test robot
Date: Sun Jan 16 2022 - 13:11:37 EST
Hi Axel,
FYI, the error/warning still remains.
tree: https://github.com/ammarfaizi2/linux-block google/android/kernel/common/android12-5.4
head: bdf17ba628090156b539b1474eb5c636eeaf571b
commit: b69f713e60d03ae448e5c9fd92e5b0b193dea7be [6517/9999] BACKPORT: FROMGIT: userfaultfd: add UFFDIO_CONTINUE ioctl
config: x86_64-randconfig-a012 (https://download.01.org/0day-ci/archive/20220117/202201170247.Cir3moOM-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c63a3175c2947e8c1a2d3bbe16a8586600705c54)
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://github.com/ammarfaizi2/linux-block/commit/b69f713e60d03ae448e5c9fd92e5b0b193dea7be
git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
git fetch --no-tags ammarfaizi2-block google/android/kernel/common/android12-5.4
git checkout b69f713e60d03ae448e5c9fd92e5b0b193dea7be
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross 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>
All warnings (new ones prefixed by >>):
>> fs/userfaultfd.c:1519:9: warning: variable 'ioctls_out' set but not used [-Wunused-but-set-variable]
__u64 ioctls_out;
^
1 warning generated.
vim +/ioctls_out +1519 fs/userfaultfd.c
1311
1312 static int userfaultfd_register(struct userfaultfd_ctx *ctx,
1313 unsigned long arg)
1314 {
1315 struct mm_struct *mm = ctx->mm;
1316 struct vm_area_struct *vma, *prev, *cur;
1317 int ret;
1318 struct uffdio_register uffdio_register;
1319 struct uffdio_register __user *user_uffdio_register;
1320 unsigned long vm_flags, new_flags;
1321 bool found;
1322 bool basic_ioctls;
1323 unsigned long start, end, vma_end;
1324
1325 user_uffdio_register = (struct uffdio_register __user *) arg;
1326
1327 ret = -EFAULT;
1328 if (copy_from_user(&uffdio_register, user_uffdio_register,
1329 sizeof(uffdio_register)-sizeof(__u64)))
1330 goto out;
1331
1332 ret = -EINVAL;
1333 if (!uffdio_register.mode)
1334 goto out;
1335 if (uffdio_register.mode & ~UFFD_API_REGISTER_MODES)
1336 goto out;
1337 vm_flags = 0;
1338 if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING)
1339 vm_flags |= VM_UFFD_MISSING;
1340 if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) {
1341 vm_flags |= VM_UFFD_WP;
1342 /*
1343 * FIXME: remove the below error constraint by
1344 * implementing the wprotect tracking mode.
1345 */
1346 ret = -EINVAL;
1347 goto out;
1348 }
1349 if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR) {
1350 #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
1351 goto out;
1352 #endif
1353 vm_flags |= VM_UFFD_MINOR;
1354 }
1355
1356 ret = validate_range(mm, &uffdio_register.range.start,
1357 uffdio_register.range.len);
1358 if (ret)
1359 goto out;
1360
1361 start = uffdio_register.range.start;
1362 end = start + uffdio_register.range.len;
1363
1364 ret = -ENOMEM;
1365 if (!mmget_not_zero(mm))
1366 goto out;
1367
1368 down_write(&mm->mmap_sem);
1369 if (!mmget_still_valid(mm))
1370 goto out_unlock;
1371 vma = find_vma_prev(mm, start, &prev);
1372 if (!vma)
1373 goto out_unlock;
1374
1375 /* check that there's at least one vma in the range */
1376 ret = -EINVAL;
1377 if (vma->vm_start >= end)
1378 goto out_unlock;
1379
1380 /*
1381 * If the first vma contains huge pages, make sure start address
1382 * is aligned to huge page size.
1383 */
1384 if (is_vm_hugetlb_page(vma)) {
1385 unsigned long vma_hpagesize = vma_kernel_pagesize(vma);
1386
1387 if (start & (vma_hpagesize - 1))
1388 goto out_unlock;
1389 }
1390
1391 /*
1392 * Search for not compatible vmas.
1393 */
1394 found = false;
1395 basic_ioctls = false;
1396 for (cur = vma; cur && cur->vm_start < end; cur = cur->vm_next) {
1397 cond_resched();
1398
1399 BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^
1400 !!(cur->vm_flags & __VM_UFFD_FLAGS));
1401
1402 /* check not compatible vmas */
1403 ret = -EINVAL;
1404 if (!vma_can_userfault(cur, vm_flags))
1405 goto out_unlock;
1406
1407 /*
1408 * UFFDIO_COPY will fill file holes even without
1409 * PROT_WRITE. This check enforces that if this is a
1410 * MAP_SHARED, the process has write permission to the backing
1411 * file. If VM_MAYWRITE is set it also enforces that on a
1412 * MAP_SHARED vma: there is no F_WRITE_SEAL and no further
1413 * F_WRITE_SEAL can be taken until the vma is destroyed.
1414 */
1415 ret = -EPERM;
1416 if (unlikely(!(cur->vm_flags & VM_MAYWRITE)))
1417 goto out_unlock;
1418
1419 /*
1420 * If this vma contains ending address, and huge pages
1421 * check alignment.
1422 */
1423 if (is_vm_hugetlb_page(cur) && end <= cur->vm_end &&
1424 end > cur->vm_start) {
1425 unsigned long vma_hpagesize = vma_kernel_pagesize(cur);
1426
1427 ret = -EINVAL;
1428
1429 if (end & (vma_hpagesize - 1))
1430 goto out_unlock;
1431 }
1432
1433 /*
1434 * Check that this vma isn't already owned by a
1435 * different userfaultfd. We can't allow more than one
1436 * userfaultfd to own a single vma simultaneously or we
1437 * wouldn't know which one to deliver the userfaults to.
1438 */
1439 ret = -EBUSY;
1440 if (cur->vm_userfaultfd_ctx.ctx &&
1441 cur->vm_userfaultfd_ctx.ctx != ctx)
1442 goto out_unlock;
1443
1444 /*
1445 * Note vmas containing huge pages
1446 */
1447 if (is_vm_hugetlb_page(cur))
1448 basic_ioctls = true;
1449
1450 found = true;
1451 }
1452 BUG_ON(!found);
1453
1454 if (vma->vm_start < start)
1455 prev = vma;
1456
1457 ret = 0;
1458 do {
1459 cond_resched();
1460
1461 BUG_ON(!vma_can_userfault(vma, vm_flags));
1462 BUG_ON(vma->vm_userfaultfd_ctx.ctx &&
1463 vma->vm_userfaultfd_ctx.ctx != ctx);
1464 WARN_ON(!(vma->vm_flags & VM_MAYWRITE));
1465
1466 /*
1467 * Nothing to do: this vma is already registered into this
1468 * userfaultfd and with the right tracking mode too.
1469 */
1470 if (vma->vm_userfaultfd_ctx.ctx == ctx &&
1471 (vma->vm_flags & vm_flags) == vm_flags)
1472 goto skip;
1473
1474 if (vma->vm_start > start)
1475 start = vma->vm_start;
1476 vma_end = min(end, vma->vm_end);
1477
1478 new_flags = (vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags;
1479 prev = vma_merge(mm, prev, start, vma_end, new_flags,
1480 vma->anon_vma, vma->vm_file, vma->vm_pgoff,
1481 vma_policy(vma),
1482 ((struct vm_userfaultfd_ctx){ ctx }),
1483 vma_get_anon_name(vma));
1484 if (prev) {
1485 vma = prev;
1486 goto next;
1487 }
1488 if (vma->vm_start < start) {
1489 ret = split_vma(mm, vma, start, 1);
1490 if (ret)
1491 break;
1492 }
1493 if (vma->vm_end > end) {
1494 ret = split_vma(mm, vma, end, 0);
1495 if (ret)
1496 break;
1497 }
1498 next:
1499 /*
1500 * In the vma_merge() successful mprotect-like case 8:
1501 * the next vma was merged into the current one and
1502 * the current one has not been updated yet.
1503 */
1504 vma->vm_flags = new_flags;
1505 vma->vm_userfaultfd_ctx.ctx = ctx;
1506
1507 if (is_vm_hugetlb_page(vma) && uffd_disable_huge_pmd_share(vma))
1508 hugetlb_unshare_all_pmds(vma);
1509
1510 skip:
1511 prev = vma;
1512 start = vma->vm_end;
1513 vma = vma->vm_next;
1514 } while (vma && vma->vm_start < end);
1515 out_unlock:
1516 up_write(&mm->mmap_sem);
1517 mmput(mm);
1518 if (!ret) {
> 1519 __u64 ioctls_out;
1520
1521 ioctls_out = basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC :
1522 UFFD_API_RANGE_IOCTLS;
1523
1524 /* CONTINUE ioctl is only supported for MINOR ranges. */
1525 if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR))
1526 ioctls_out &= ~((__u64)1 << _UFFDIO_CONTINUE);
1527
1528 /*
1529 * Now that we scanned all vmas we can already tell
1530 * userland which ioctls methods are guaranteed to
1531 * succeed on this range.
1532 */
1533 if (put_user(basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC :
1534 UFFD_API_RANGE_IOCTLS,
1535 &user_uffdio_register->ioctls))
1536 ret = -EFAULT;
1537 }
1538 out:
1539 return ret;
1540 }
1541
---
0-DAY CI Kernel Test Service, Intel Corporation
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