[LTP] [PATCH v4] mmap22.c: Test for new MAP_DROPPABLE flag for mmap

[Jan Stancek]

On Wed, May 14, 2025 at 11:04 AM Li Wang <liwang@redhat.com> wrote:
>
> On Wed, May 14, 2025 at 4:52 PM Jan Stancek via ltp <ltp@lists.linux.it> wrote:
> >
> > On Tue, May 13, 2025 at 5:44 AM Wei Gao <wegao@suse.com> wrote:
> > >
> > > On Mon, May 12, 2025 at 10:43:55AM +0200, Jan Stancek wrote:
> > > > Is anyone else seeing this test failing on recent 6.15-rc5 kernels?
> > > >
> > > > ==== mmap22 ====
> > > > command: mmap22
> > > > tst_tmpdir.c:316: TINFO: Using /tmp/LTP_mmazCULNN as tmpdir (tmpfs filesystem)
> > > > tst_test.c:1938: TINFO: LTP version: 20250130-253-g4a0e3a8fa
> > > > tst_test.c:1942: TINFO: Tested kernel:
> > > > 6.15.0-0.rc5.250509g9c69f8884904.47.eln148.x86_64 #1 SMP
> > > > PREEMPT_DYNAMIC Fri May  9 15:17:31 UTC 2025 x86_64
> > > > tst_kconfig.c:88: TINFO: Parsing kernel config
> > > > '/lib/modules/6.15.0-0.rc5.250509g9c69f8884904.47.eln148.x86_64/build/.config'
> > > > tst_test.c:1758: TINFO: Overall timeout per run is 0h 05m 54s
> > > > mmap22.c:55: TFAIL: MAP_DROPPABLE did not drop memory within the timeout period.
> > > >
> > >
> > > I have tested rc5/6 and both give pass result.
> >
> > I do see it fail almost daily on multiple arches (VMs and baremetal),
> > maybe some difference in our config.
>
> Have you tried the original self-test (without using Cgroup)?
> If it still fails, consider it a kernel issue.

I'll have a closer look and try manually. At first glance at test, I
suspect compiler
doing something clever for:
                for (;;)
                        *(char *)malloc(page_size) = 'B';

>
> --
> Regards,
> Li Wang
>