From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leo Liang Date: Tue, 6 Jul 2021 11:27:48 +0800 Subject: [LTP] [PATCH 1/1] cgroup/cgroup_regression_test: Fix umount failure In-Reply-To: References: <20210628033002.GA1469@andestech.com> Message-ID: <20210706032748.GA16346@andestech.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it Hi, Sorry for the late response and thanks for all the replies and suggestions. I am running on a rather new RISC-V platform (Andes/AE350) and with 5.4.0 off-tree kernel. The umount in cgroup_regression_test mostly failed at test_2 and test_3, so it would show FAIL result (mount not successfully executed) at test_3 and test_5 (test_4 shows TCONF on my platform). On Mon, Jun 28, 2021 at 03:08:39PM +0200, Cyril Hrubis wrote: > Hi! > > I would like a short comment close to the syncs. When I converted > > cpuset_regression_test.sh, I would have removed the sync in there, if > > there wouldn't have been any comment. > > Most of the time syncs are not required and just added by paranoid > > developers, but if there is a real reason, I think it should be stated > > in a comment. > > Sounds reasonable to me, can we please add a comment there? Hi Cyril and Joerg, Sounds reasonable to me as well, will send a v2 patch with comment. > -- > Cyril Hrubis > chrubis@suse.cz > Agree with this. Are all these sync really needed? Or just some? Hi Petr, I've written a script containing only the following sequence " mount 'cgroup mntpoint' " " mkdir 'under cgroup mntpoint' " " rmdir 'under cgroup mntpoint' " " umount 'cgroup mntpoint' " " mount 'cgroup mntpoint' " and it could trigger the fail. But only bumped into the umount fail when doing test_2 and test_3 in the cgroup_regression_test. I am adding syncs in every sub-tests that execute the above sequence now. Should them be added only at the places where umount failure did occur ? > Kind regards, > Petr > IMO, Even we call sync, this umount may fail because sync ensures > nothing. Why not use tst_umount? Hi Yang, I think this might be a timing issue and a little delay could fix this problem. (e.g. 'sleep 1') Using 'sync' here IMHO would be more descriptive and has a semantic meaning. Speaking of tst_umount, do you mean to convert this test to C code ? > Best Regards > Yang Xu Best regards, Leo