From 77dc9d662f80b9f4eb450df27f60a0a9b3c97785 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Thu, 16 Oct 2025 16:03:48 +0100 Subject: [PATCH] tests/tcg/multiarch/linux/linux-test: Don't try to test atime update MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The linux-test test includes an attempt to check the utime and stat syscalls by setting the atime and mtime of a file to specific values, and then calling stat() to check that the values read back correctly. Unfortunately this is flaky, as it will fail if some other process (for instance a virus scanner, backup program, etc) gets in and reads the file between the utime() and stat() call, resulting in a host syscall sequence like this: utimensat(AT_FDCWD, "file2", [{tv_sec=1001, tv_nsec=0} /* 1970-01-01T01:16:41+0100 */, {tv_sec=1000, tv_nsec=0} /* 1970-01-01T01:16:40+0100 */], 0) = 0 # successfully set atime to 1001 and mtime to 1000 statx(AT_FDCWD, "file2", AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT, STATX_BASIC_STATS, {stx_mask=STATX_BASIC_STATS|STATX_MNT_ID, stx_blksize=4096, stx_attributes=0, stx_nlink=1, stx_uid=32808, stx_gid=32808, stx_mode=S_IFREG|0600, stx_ino=21659016, stx_size=100, stx_blocks=8, stx_attributes_mask=STATX_ATTR_COMPRESSED|STATX_ATTR_IMMUTABLE| STATX_ATTR_APPEND|STATX_ATTR_NODUMP|STATX_ATTR_ENCRYPTED| STATX_ATTR_AUTOMOUNT|STATX_ATTR_MOUNT_ROOT|STATX_ATTR_VERITY| STATX_ATTR_DAX, stx_atime={tv_sec=1760091862, tv_nsec=63509009} /* 2025-10-10T11:24:22.063509009+0100 */, stx_ctime={tv_sec=1760091862, tv_nsec=63509009} /* 2025-10-10T11:24:22.063509009+0100 */, stx_mtime={tv_sec=1000, tv_nsec=0} /* 1970-01-01T01:16:40+0100 */, stx_rdev_major=0, stx_rdev_minor=0, stx_dev_major=252, stx_dev_minor=0, stx_mnt_id=0x1f}) = 0 # but when we statx the file, we get back an mtime of 1000 # but an atime corresponding to when the other process read it and which will cause the test program to fail with the error message "stat time". In theory we could defend against this by e.g. operating on files in a dummy loopback mount filesystem which we mounted as 'noatime', but this isn't worth the hassle. Just drop the check on atime. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell Reviewed-by: Thomas Huth Reviewed-by: Richard Henderson Message-ID: <20251016150357.876415-4-alex.bennee@linaro.org> Signed-off-by: Alex Bennée --- tests/tcg/multiarch/linux/linux-test.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/tests/tcg/multiarch/linux/linux-test.c b/tests/tcg/multiarch/linux/linux-test.c index 64f57cb287..bf6e0fda26 100644 --- a/tests/tcg/multiarch/linux/linux-test.c +++ b/tests/tcg/multiarch/linux/linux-test.c @@ -155,9 +155,14 @@ static void test_file(void) error("stat mode"); if ((st.st_mode & 0777) != 0600) error("stat mode2"); - if (st.st_atime != 1001 || - st.st_mtime != 1000) + /* + * Only check mtime, not atime: other processes such as + * virus scanners might race with this test program and get + * in and update the atime, causing random failures. + */ + if (st.st_mtime != 1000) { error("stat time"); + } chk_error(stat(tmpdir, &st)); if (!S_ISDIR(st.st_mode)) -- 2.47.3