RE: [PATCH v11 5/9] Reimplement RLIMIT_MSGQUEUE on top of ucounts

["Ma, XinjianX" <xinjianx.ma@intel.com>]

> -----Original Message-----
> From: Alexey Gladkov <legion@kernel.org>
> Sent: Wednesday, August 18, 2021 9:11 PM
> To: Eric W. Biederman <ebiederm@xmission.com>
> Cc: Ma, XinjianX <xinjianx.ma@intel.com>; linux-kselftest@vger.kernel.org;
> lkp <lkp@intel.com>; akpm@linux-foundation.org; axboe@kernel.dk;
> christian.brauner@ubuntu.com; containers@lists.linux-foundation.org;
> jannh@google.com; keescook@chromium.org; kernel-
> hardening@lists.openwall.com; linux-kernel@vger.kernel.org; linux-
> mm@kvack.org; oleg@redhat.com; torvalds@linux-foundation.org
> Subject: Re: [PATCH v11 5/9] Reimplement RLIMIT_MSGQUEUE on top of
> ucounts
> 
> On Tue, Aug 17, 2021 at 10:47:14AM -0500, Eric W. Biederman wrote:
> > "Ma, XinjianX" <xinjianx.ma@intel.com> writes:
> >
> > > Hi Alexey,
> > >
> > > When lkp team run kernel selftests, we found after these series of
> > > patches, testcase mqueue: mq_perf_tests in kselftest failed with
> following message.
> >
> > Which kernel was this run against?
> >
> > Where can the mq_perf_tests that you ran and had problems with be
> found?
> >
> > During your run were you using user namespaces as part of your test
> > environment?
> >
> > The error message too many files corresponds to the error code EMFILES
> > which is the error code that is returned when the rlimit is reached.
> >
> > One possibility is that your test environment was run in a user
> > namespace and so you wound up limited by rlimit of the user who
> > created the user namespace at the point of user namespace creation.
> >
> > At this point if you can give us enough information to look into this
> > and attempt to reproduce it that would be appreciated.
> 
> I was able to reproduce it on master without using user namespace.
> I suspect that the maximum value is not assigned here [1]:
> 
> set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE,
> task_rlimit(&init_task, RLIMIT_MSGQUEUE));
> 
> [1]
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kerne
> l/fork.c#n832
Thank you for confirming the issue. And will you plan to fix this issue?
If it's your plan, kindly add following tag as appropriate
Reported-by: kernel test robot <xinjianx.ma@intel.com>


> 
> > > If you confirm and fix the issue, kindly add following tag as
> > > appropriate
> > > Reported-by: kernel test robot lkp@intel.com
> > >
> > > ```
> > > # selftests: mqueue: mq_perf_tests
> > > #
> > > # Initial system state:
> > > #       Using queue path:                       /mq_perf_tests
> > > #       RLIMIT_MSGQUEUE(soft):                  819200
> > > #       RLIMIT_MSGQUEUE(hard):                  819200
> > > #       Maximum Message Size:                   8192
> > > #       Maximum Queue Size:                     10
> > > #       Nice value:                             0
> > > #
> > > # Adjusted system state for testing:
> > > #       RLIMIT_MSGQUEUE(soft):                  (unlimited)
> > > #       RLIMIT_MSGQUEUE(hard):                  (unlimited)
> > > #       Maximum Message Size:                   16777216
> > > #       Maximum Queue Size:                     65530
> > > #       Nice value:                             -20
> > > #       Continuous mode:                        (disabled)
> > > #       CPUs to pin:                            3
> > > # ./mq_perf_tests: mq_open() at 296: Too many open files not ok 2
> > > selftests: mqueue: mq_perf_tests # exit=1
> > > ```
> > >
> > > Test env:
> > > rootfs: debian-10
> > > gcc version: 9
> > >
> > > ------
> > > Thanks
> > > Ma Xinjian
> >
> > Eric
> >
> 
> --
> Rgrds, legion