-----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/kern... 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=1Test env: rootfs: debian-10 gcc version: 9
Thanks Ma Xinjian
Eric
-- Rgrds, legion