On 04-29 15:20, Pratyush Yadav wrote: > On Tue, Apr 28 2026, Pasha Tatashin wrote: > > > On 04-04 10:24, Pratyush Yadav wrote: > >> From: "Pratyush Yadav (Google)" <[email protected]> > >> > >> Hi, > >> > >> This series adds some tests for memfd preservation across a live update. > >> Currently memfd is only tested indirectly via luo_kexec_simple or > >> luo_multi_session. Add a dedicated test suite for it. > >> > >> Patches 1 and 2 are preparatory, adding base framework and helpers, and > >> the other patches each add a test. Some of the code is taken from the > >> libluo patches [0] I sent a while ago. > >> > >> [0] > >> https://lore.kernel.org/linux-mm/[email protected]/ > > > > Here are few observations that I noticed when I tried to run your tests: > > > > 1. The '-h' tells you nothing about --stage argument: > > > > root@liveupdate-vm:~/liveupdate# ./luo_memfd -h > > Usage: ./luo_memfd [-h|-l|-d] [-t|-T|-v|-V|-f|-F|-r name] > > -h print help > > -l list all tests > > -d enable debug prints > > > > -t name include test > > -T name exclude test > > -v name include variant > > -V name exclude variant > > -f name include fixture > > -F name exclude fixture > > -r name run specified test > > ... > > Yeah, unfortunately that is a side effect of using test_harness_run(), > which does not know anything about the options specific to our test. > > > > > 2. '-l' does not work after you run stage1, do you keep /dev/liveupdate > > open? That is not needed, we only need to keep session open. > > Oh yeah, I keep forgetting that is no longer needed. The main process > closes the FD but the forked daemons hold a reference. I can clean that > up via a fixture. > > > > > root@liveupdate-vm:~/liveupdate# ./luo_memfd -l > > 1..0 # SKIP Failed to open /dev/liveupdate (Device or resource busy) > > device. Is LUO enabled? > > > > 3. Stage 1 has proper [STAGE 1] prefix, but no [STAGE 2] prefix for > > Because stage 2 has no prints, all the prints are coming from the > selftest harness. Those same lines are also not prefixed in stage 1. If > you'd like, I can add a print beforehand that shows which stage is
Yes, please, add a least one [STAGE 2] print. > running. Other than that, I don't see what else we can do. I don't want > to modify the selftest harness. > > > stage 2: > > # Starting 4 tests from 1 test cases. > > # RUN global.memfd_data ... > > # [STAGE 1] Forking persistent child to hold sessions... > > # [STAGE 1] Child PID: 245. Resources are pinned. > > # [STAGE 1] You may now perform kexec reboot. > > # OK global.memfd_data > > ok 1 global.memfd_data > > # RUN global.zero_memfd ... > > # [STAGE 1] Forking persistent child to hold sessions... > > # [STAGE 1] Child PID: 247. Resources are pinned. > > # [STAGE 1] You may now perform kexec reboot. > > # OK global.zero_memfd > > ok 2 global.zero_memfd > > # RUN global.preserved_ops ... > > # OK global.preserved_ops > > ok 3 global.preserved_ops > > # RUN global.fallocate_memfd ... > > # [STAGE 1] Forking persistent child to hold sessions... > > # [STAGE 1] Child PID: 250. Resources are pinned. > > # [STAGE 1] You may now perform kexec reboot. > > # OK global.fallocate_memfd > > ok 4 global.fallocate_memfd > > # PASSED: 4 / 4 tests passed. > > # Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0 > > > > ./do_kexec > > > > root@liveupdate-vm:~/liveupdate# ./luo_memfd > > TAP version 13 > > 1..4 > > # Starting 4 tests from 1 test cases. > > # RUN global.memfd_data ... > > # OK global.memfd_data > > ok 1 global.memfd_data > > # RUN global.zero_memfd ... > > # OK global.zero_memfd > > ok 2 global.zero_memfd > > # RUN global.preserved_ops ... > > # SKIP test only expected to run on stage 1 > > # OK global.preserved_ops > > ok 3 global.preserved_ops # SKIP test only expected to run on stage 1 > > # RUN global.fallocate_memfd ... > > # OK global.fallocate_memfd > > ok 4 global.fallocate_memfd > > # PASSED: 4 / 4 tests passed. > > # 1 skipped test(s) detected. Consider enabling relevant config options to > > improve coverage. > > # Totals: pass:3 fail:0 xfail:0 xpass:0 skip:1 error:0 > > > > 4. I also do not like that we now have duplicated stage parsing code in > > luo_test(), perhaps we should add our own test_harness_run() variant > > that depends on stage, and use it in both current tests, and the new > > memfd tests. > > Sounds good in principle, but unfortunately ends up duplicating a lot of > logic in test_harness_run() that is not a good idea IMO. We should work > with the harness not fork off into our own. > > I suppose we can refactor some of the logic there to split into > functions that we can then use in our luo_test_harness_run(), but > keeping the option parsing logic in sync is going to be difficult. > > And for the duplicated logic, I agree. I thought about cleaning it up > but was feeling lazy... Well now that you have called it out let me see > what I can do. The main point is that the luo_sessions and luo_memfds tests should use a common framework, whether that's luo_test_harness_run() or the generic test_harness_run(). I don't have a definitive answer for this, so I recommend tinkering with it to see what works best. Pasha > > [...] > > -- > Regards, > Pratyush Yadav
