tree: https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git work.iov_iter_get_pages head: eaf51d32a6d0a79ce7096996fd432ebb03b725e1 commit: 380244e4bdf81bb2e69ed68827d9718d5bfc1bb4 [21/33] iov_iter: massage calling conventions for first_{iovec,bvec}_segment() config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20220618/202206181816.oFNEwB8K-lkp@xxxxxxxxx/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 91688716ba49942051dccdf7b9c4f81a7ec8feaf) 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://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git/commit/?id=380244e4bdf81bb2e69ed68827d9718d5bfc1bb4 git remote add viro-vfs https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git git fetch --no-tags viro-vfs work.iov_iter_get_pages git checkout 380244e4bdf81bb2e69ed68827d9718d5bfc1bb4 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): >> lib/iov_iter.c:1392:24: warning: variable 'len' is uninitialized when used here [-Wuninitialized] return min_t(size_t, len, res * PAGE_SIZE - *start); ^~~ include/linux/minmax.h:104:48: note: expanded from macro 'min_t' #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) ^ include/linux/minmax.h:38:14: note: expanded from macro '__careful_cmp' __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op)) ^ include/linux/minmax.h:31:25: note: expanded from macro '__cmp_once' typeof(x) unique_x = (x); \ ^ lib/iov_iter.c:1361:12: note: initialize the variable 'len' to silence this warning size_t len; ^ = 0 1 warning generated. vim +/len +1392 lib/iov_iter.c 1356 1357 static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, 1358 struct page ***pages, size_t maxsize, 1359 unsigned int maxpages, size_t *start) 1360 { 1361 size_t len; 1362 int n, res; 1363 1364 if (maxsize > i->count) 1365 maxsize = i->count; 1366 if (!maxsize) 1367 return 0; 1368 if (maxsize > LONG_MAX) 1369 maxsize = LONG_MAX; 1370 1371 if (likely(user_backed_iter(i))) { 1372 unsigned int gup_flags = 0; 1373 unsigned long addr; 1374 1375 if (iov_iter_rw(i) != WRITE) 1376 gup_flags |= FOLL_WRITE; 1377 if (i->nofault) 1378 gup_flags |= FOLL_NOFAULT; 1379 1380 addr = first_iovec_segment(i, &maxsize, start); 1381 n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1382 if (n > maxpages) 1383 n = maxpages; 1384 if (*pages) { 1385 *pages = get_pages_array(n); 1386 if (!*pages) 1387 return -ENOMEM; 1388 } 1389 res = get_user_pages_fast(addr, n, gup_flags, *pages); 1390 if (unlikely(res <= 0)) 1391 return res; > 1392 return min_t(size_t, len, res * PAGE_SIZE - *start); 1393 } 1394 if (iov_iter_is_bvec(i)) { 1395 struct page **p; 1396 struct page *page; 1397 1398 page = first_bvec_segment(i, &maxsize, start); 1399 n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1400 if (n > maxpages) 1401 n = maxpages; 1402 p = *pages; 1403 if (!p) { 1404 *pages = p = get_pages_array(n); 1405 if (!p) 1406 return -ENOMEM; 1407 } 1408 for (int k = 0; k < n; k++) 1409 get_page(*p++ = page++); 1410 return min_t(size_t, maxsize, n * PAGE_SIZE - *start); 1411 } 1412 if (iov_iter_is_pipe(i)) 1413 return pipe_get_pages(i, pages, maxsize, maxpages, start); 1414 if (iov_iter_is_xarray(i)) 1415 return iter_xarray_get_pages(i, pages, maxsize, maxpages, 1416 start); 1417 return -EFAULT; 1418 } 1419 -- 0-DAY CI Kernel Test Service https://01.org/lkp
