Two bugs that only show up on 64-bit architectures: - readdir_r() truncates the directory offset to an int. On ext4 it fails within the first few entries of almost every directory (since v6.19), or returns the next-to-last entry twice and never the last one (v6.15 to v6.18). Patch 1.
- FD_SET(), FD_CLR() and FD_ISSET() build their masks from an int, so they use the wrong bits for fds 31-63 of each 64-bit word, and select() on fd 40 fails with EBADF. Patch 2, with a test in patch 3. There is no selftest for patch 1: it needs a directory with large offsets, and nolibc-test only lists /proc/self, whose offsets are small. I tested it with a small program that lists a directory with readdir_r() instead. Changes in v2: - Dropped Cc: stable from patches 1 and 2, which are otherwise unchanged. - Patch 3: dropped the select() test, and moved the FD_* test to the stdlib tests, with its helper in the same order as the test cases (Thomas). It is also shorter: FD_CLR() is now checked on a set filled with memset(). - Rebased on nolibc/for-next 6f114ae7b600. v1: https://lore.kernel.org/all/[email protected]/ Testing, with GCC 16.2, on x86_64 and i386 natively and on arm, arm64 and sparc64 under qemu-user: - nolibc-test, all tests: no failures before or after the series. The only difference is the new fd_set test, which passes, also with clang on x86_64 and against glibc (make libc-test). - Without patch 2, fd_set fails on the 64-bit architectures: with the default UBSan flags the run stops at fd_set on the sanitizer trap, and without them the test reports [FAIL] (checked on x86_64 and arm64). It passes on i386 and arm, which are not affected. - The readdir_r() program, on ext4, on x86_64, arm64 and sparc64: before, it fails on /etc after 4 of 215 entries, /usr/include after 1 of 1467 and /usr/lib after 2 of 6229. After, it lists as many entries as glibc. A native i386 build was already correct. - Built for x86_64 against nolibc from before commit 4ada5679f18d, the same program lists a directory holding "..", "code" and "." as "..", "code", "code". Danish Khateeb (3): tools/nolibc: fix readdir_r() with 64-bit directory offsets tools/nolibc: fix FD_SET(), FD_CLR() and FD_ISSET() on 64-bit selftests/nolibc: test the FD_* macros tools/include/nolibc/dirent.h | 7 ++++--- tools/include/nolibc/sys/select.h | 6 +++--- tools/testing/selftests/nolibc/nolibc-test.c | 21 ++++++++++++++++++++ 3 files changed, 28 insertions(+), 6 deletions(-) base-commit: 6f114ae7b6006ca7cf72e3e3348d263bbfec4525 -- 2.55.0
