On Thu, Jan 06, 2022 at 08:35:18AM +0100, Jiri Olsa wrote: > On Wed, Jan 05, 2022 at 12:40:34PM -0800, Andrii Nakryiko wrote: > > On Tue, Jan 4, 2022 at 4:10 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > > > > > The tc_redirect umounts /sys in the new namespace, which can be > > > mounted as shared and cause global umount. The lazy umount also > > > takes down mounted trees under /sys like debugfs, which won't be > > > available after sysfs mounts again and could cause fails in other > > > tests. > > > > > > # cat /proc/self/mountinfo | grep debugfs > > > 34 23 0:7 / /sys/kernel/debug rw,nosuid,nodev,noexec,relatime shared:14 - debugfs debugfs rw > > > # cat /proc/self/mountinfo | grep sysfs > > > 23 86 0:22 / /sys rw,nosuid,nodev,noexec,relatime shared:2 - sysfs sysfs rw > > > # mount | grep debugfs > > > debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime) > > > > > > # ./test_progs -t tc_redirect > > > #164 tc_redirect:OK > > > Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED > > > > > > # mount | grep debugfs > > > # cat /proc/self/mountinfo | grep debugfs > > > # cat /proc/self/mountinfo | grep sysfs > > > 25 86 0:22 / /sys rw,relatime shared:2 - sysfs sysfs rw > > > > > > Making the sysfs private under the new namespace so the umount won't > > > trigger the global sysfs umount. > > > > Hey Jiri, > > > > Thanks for the fix. Did you try making tc_redirect non-serial again > > (s/serial_test_tc_redirect/test_tc_redirect/) and doing parallelized > > test_progs run (./test_progs -j) in a tight loop for a while? I > > suspect this might have been an issue forcing us to make this test > > serial in the first place, so now that it's fixed, we can make > > parallel test_progs a bit faster. > > hi, > right, will try so I can't reproduce the issue in the first place - that means without my fix and with reverted serial_test_tc_redirect change - by running parallelized test_progs, could you guys try it? jirka
