Device-DAX explicitly disallows MAP_PRIVATE mappings. Signed-off-by: Dan Williams <dan.j.williams(a)intel.com&gt; --- test/device-dax.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/test/device-dax.c b/test/device-dax.c index 34ca284f2ef5..a14e2a95db7e 100644 --- a/test/device-dax.c +++ b/test/device-dax.c @@ -113,6 +113,12 @@ static int test_device_dax(int loglevel, struct ndctl_test *test, return -ENXIO; } + buf = mmap(NULL, 2UL << 20, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); + if (buf != MAP_FAILED) { + fprintf(stderr, "%s: expected MAP_PRIVATE failure\n", path); + return -ENXIO; + } + buf = mmap(NULL, 2UL << 20, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); p = (int *) (buf + (1UL << 20)); *p = 0;