Re: [linus:master] [selftests] 465b05bae5: kernel-selftests.landlock.audit_test.audit.tsync_override_log_subdomains_off.fail

Re: [linus:master] [selftests] 465b05bae5: kernel-selftests.landlock.audit_test.audit.tsync_override_log_subdomains_off.fail

[Thomas Weißschuh]

Hi Mickaël and Günther,

I received the following report about a failing landlock selftest from
the 0day bot.

On Mon, May 11, 2026 at 10:15:00PM +0800, kernel test robot wrote:
> kernel test robot noticed "kernel-selftests.landlock.audit_test.audit.tsync_override_log_subdomains_off.fail" on:
> 
> commit: 465b05bae5ac553c13315681c1490dc565337771 ("selftests: harness: Restore order of test functions")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> 
> 
> in testcase: kernel-selftests
> version: kernel-selftests-x86_64-9f2693489ef8-1_20260201
> with following parameters:
> 
> 	group: landlock
> 
> config: x86_64-rhel-9.4-kselftests
> compiler: gcc-14
> test machine: 16 threads Intel(R) Core(TM) i7-13620H (Raptor Lake) with 32G memory
> 
> (please refer to attached dmesg/kmsg for entire log/backtrace)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@intel.com>
> | Closes: https://lore.kernel.org/oe-lkp/202605111649.a8b30a62-lkp@intel.com

I was unable to run the landlock selftests myself, on my machines they are
failing at runtime with all kinds of colorful errors. Are the requirements
explained somewhere?

> # #  RUN           audit.tsync_override_log_subdomains_off ...
> # # audit_test.c:591:tsync_override_log_subdomains_off:Expected 0 (0) == matches_log_signal(_metadata, self->audit_fd, child_data.parent_pid, NULL) (-11)

This error number means "EAGAIN 11 Resource temporarily unavailable",
so it could be a temporary error.

Can you reproduce this issue? Is it really dependent on my patch as
blamed above? If so, does the selftest rely on the previous, incorrect order?

> # # tsync_override_log_subdomains_off: Test failed
> # #          FAIL  audit.tsync_override_log_subdomains_off
> # not ok 5 audit.tsync_override_log_subdomains_off


Thomas

Re: [linus:master] [selftests] 465b05bae5: kernel-selftests.landlock.audit_test.audit.tsync_override_log_subdomains_off.fail

[Mickaël Salaün]

Hi Thomas,

Thanks for the report.

On Tue, May 12, 2026 at 11:27:42AM +0200, Thomas Weißschuh wrote:
> Hi Mickaël and Günther,
> 
> I received the following report about a failing landlock selftest from
> the 0day bot.
> 
> On Mon, May 11, 2026 at 10:15:00PM +0800, kernel test robot wrote:
> > kernel test robot noticed "kernel-selftests.landlock.audit_test.audit.tsync_override_log_subdomains_off.fail" on:
> > 
> > commit: 465b05bae5ac553c13315681c1490dc565337771 ("selftests: harness: Restore order of test functions")
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> > 
> > 
> > in testcase: kernel-selftests
> > version: kernel-selftests-x86_64-9f2693489ef8-1_20260201
> > with following parameters:
> > 
> > 	group: landlock

This group is correct but I'm wondering why the maintainer (me) and the
reviewer (Günther) weren't in Cc.

What do we need to do to subscribe to such report?  Why isn't
automatically inferred from the MAINTAINER file?

> > 
> > config: x86_64-rhel-9.4-kselftests
> > compiler: gcc-14
> > test machine: 16 threads Intel(R) Core(TM) i7-13620H (Raptor Lake) with 32G memory
> > 
> > (please refer to attached dmesg/kmsg for entire log/backtrace)
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <oliver.sang@intel.com>
> > | Closes: https://lore.kernel.org/oe-lkp/202605111649.a8b30a62-lkp@intel.com
> 
> I was unable to run the landlock selftests myself, on my machines they are
> failing at runtime with all kinds of colorful errors. Are the requirements
> explained somewhere?

I'm curious about the errors you get.  They are standard kselftests that
should work following this workflow:

  make TARGETS=landlock O=build kselftest-gen_tar

and then running ./build/kselftests/kselftest_install/run_kselftest.sh
as root in a VM.  The required kernel configuration is listed in
tools/testing/selftests/landlock/config

To make it easier, we wrote a wrapper to test everything with UML:
https://github.com/landlock-lsm/landlock-test-tools (see check-linux.sh)

> 
> > # #  RUN           audit.tsync_override_log_subdomains_off ...
> > # # audit_test.c:591:tsync_override_log_subdomains_off:Expected 0 (0) == matches_log_signal(_metadata, self->audit_fd, child_data.parent_pid, NULL) (-11)
> 
> This error number means "EAGAIN 11 Resource temporarily unavailable",
> so it could be a temporary error.

Yes, the test is flaky under pressure.

> 
> Can you reproduce this issue? Is it really dependent on my patch as
> blamed above? If so, does the selftest rely on the previous, incorrect order?

I don't think it directly depends on your patch but it might be a side
effect.  Anyway, I've been working on fixing this kind of issue and just
sent a fix:
https://lore.kernel.org/r/20260513105112.140137-2-mic@digikod.net

> 
> > # # tsync_override_log_subdomains_off: Test failed
> > # #          FAIL  audit.tsync_override_log_subdomains_off
> > # not ok 5 audit.tsync_override_log_subdomains_off
> 
> 
> Thomas

Re: [linus:master] [selftests] 465b05bae5: kernel-selftests.landlock.audit_test.audit.tsync_override_log_subdomains_off.fail

[Thomas Weißschuh]

On Wed, May 13, 2026 at 12:52:35PM +0200, Mickaël Salaün wrote:
(...)

> > > config: x86_64-rhel-9.4-kselftests
> > > compiler: gcc-14
> > > test machine: 16 threads Intel(R) Core(TM) i7-13620H (Raptor Lake) with 32G memory
> > > 
> > > (please refer to attached dmesg/kmsg for entire log/backtrace)
> > > 
> > > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > > the same patch/commit), kindly add following tags
> > > | Reported-by: kernel test robot <oliver.sang@intel.com>
> > > | Closes: https://lore.kernel.org/oe-lkp/202605111649.a8b30a62-lkp@intel.com
> > 
> > I was unable to run the landlock selftests myself, on my machines they are
> > failing at runtime with all kinds of colorful errors. Are the requirements
> > explained somewhere?
> 
> I'm curious about the errors you get.  They are standard kselftests that
> should work following this workflow:
> 
>   make TARGETS=landlock O=build kselftest-gen_tar
> 
> and then running ./build/kselftests/kselftest_install/run_kselftest.sh
> as root in a VM.  The required kernel configuration is listed in
> tools/testing/selftests/landlock/config

So there are two root issues I ran into:

1) The tests can not be executed from virtiofs (as set up by virtme-ng):

 #  RUN           audit.layers ...
# audit_test.c:52:layers:Expected 0 (0) <= self->audit_fd (-13)
# audit_test.c:61:layers:Failed to initialize audit: Permission denied
# layers: Test failed
#          FAIL  audit.layers
not ok 1 audit.layers

(The same for all other testcases)

2) $PWD needs to be the test binary directory for "./wait-pipe-sandbox" to work.

> To make it easier, we wrote a wrapper to test everything with UML:
> https://github.com/landlock-lsm/landlock-test-tools (see check-linux.sh)
> 
> > 
> > > # #  RUN           audit.tsync_override_log_subdomains_off ...
> > > # # audit_test.c:591:tsync_override_log_subdomains_off:Expected 0 (0) == matches_log_signal(_metadata, self->audit_fd, child_data.parent_pid, NULL) (-11)
> > 
> > This error number means "EAGAIN 11 Resource temporarily unavailable",
> > so it could be a temporary error.
> 
> Yes, the test is flaky under pressure.
> 
> > 
> > Can you reproduce this issue? Is it really dependent on my patch as
> > blamed above? If so, does the selftest rely on the previous, incorrect order?
> 
> I don't think it directly depends on your patch but it might be a side
> effect.  Anyway, I've been working on fixing this kind of issue and just
> sent a fix:
> https://lore.kernel.org/r/20260513105112.140137-2-mic@digikod.net

Thanks, unfortunately I can't validate that it will fix the issue at hand.


Thomas

Re: [linus:master] [selftests] 465b05bae5: kernel-selftests.landlock.audit_test.audit.tsync_override_log_subdomains_off.fail

[Mickaël Salaün]

On Mon, May 18, 2026 at 10:48:27AM +0200, Thomas Weißschuh wrote:
> On Wed, May 13, 2026 at 12:52:35PM +0200, Mickaël Salaün wrote:
> (...)
> 
> > > > config: x86_64-rhel-9.4-kselftests
> > > > compiler: gcc-14
> > > > test machine: 16 threads Intel(R) Core(TM) i7-13620H (Raptor Lake) with 32G memory
> > > > 
> > > > (please refer to attached dmesg/kmsg for entire log/backtrace)
> > > > 
> > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > > > the same patch/commit), kindly add following tags
> > > > | Reported-by: kernel test robot <oliver.sang@intel.com>
> > > > | Closes: https://lore.kernel.org/oe-lkp/202605111649.a8b30a62-lkp@intel.com
> > > 
> > > I was unable to run the landlock selftests myself, on my machines they are
> > > failing at runtime with all kinds of colorful errors. Are the requirements
> > > explained somewhere?
> > 
> > I'm curious about the errors you get.  They are standard kselftests that
> > should work following this workflow:
> > 
> >   make TARGETS=landlock O=build kselftest-gen_tar
> > 
> > and then running ./build/kselftests/kselftest_install/run_kselftest.sh
> > as root in a VM.  The required kernel configuration is listed in
> > tools/testing/selftests/landlock/config
> 
> So there are two root issues I ran into:
> 
> 1) The tests can not be executed from virtiofs (as set up by virtme-ng):

Most filesystem tests initially set up tmpfs and then use it.

I'm using virtme-ng too, see the
https://github.com/landlock-lsm/landlock-test-tools

 ARCH=x86_64 .../check-linux.sh build_light kselftest

> 
>  #  RUN           audit.layers ...
> # audit_test.c:52:layers:Expected 0 (0) <= self->audit_fd (-13)
> # audit_test.c:61:layers:Failed to initialize audit: Permission denied
> # layers: Test failed
> #          FAIL  audit.layers
> not ok 1 audit.layers
> 
> (The same for all other testcases)

It looks like the tests are not run with enough privileges.  Do you run
them as root?  Does the kernel has the required config set?

> 
> 2) $PWD needs to be the test binary directory for "./wait-pipe-sandbox" to work.

Yes.  run_kselftest.sh should handle that.

> 
> > To make it easier, we wrote a wrapper to test everything with UML:
> > https://github.com/landlock-lsm/landlock-test-tools (see check-linux.sh)
> > 
> > > 
> > > > # #  RUN           audit.tsync_override_log_subdomains_off ...
> > > > # # audit_test.c:591:tsync_override_log_subdomains_off:Expected 0 (0) == matches_log_signal(_metadata, self->audit_fd, child_data.parent_pid, NULL) (-11)
> > > 
> > > This error number means "EAGAIN 11 Resource temporarily unavailable",
> > > so it could be a temporary error.
> > 
> > Yes, the test is flaky under pressure.
> > 
> > > 
> > > Can you reproduce this issue? Is it really dependent on my patch as
> > > blamed above? If so, does the selftest rely on the previous, incorrect order?
> > 
> > I don't think it directly depends on your patch but it might be a side
> > effect.  Anyway, I've been working on fixing this kind of issue and just
> > sent a fix:
> > https://lore.kernel.org/r/20260513105112.140137-2-mic@digikod.net
> 
> Thanks, unfortunately I can't validate that it will fix the issue at hand.

I pushed it to -next, we'll see but I'm pretty sure this is the issue.

Re: [linus:master] [selftests] 465b05bae5: kernel-selftests.landlock.audit_test.audit.tsync_override_log_subdomains_off.fail

[Thomas Weißschuh]

On Mon, May 18, 2026 at 11:30:42AM +0200, Mickaël Salaün wrote:
> On Mon, May 18, 2026 at 10:48:27AM +0200, Thomas Weißschuh wrote:
> > On Wed, May 13, 2026 at 12:52:35PM +0200, Mickaël Salaün wrote:
> > (...)
> > 
> > > > > config: x86_64-rhel-9.4-kselftests
> > > > > compiler: gcc-14
> > > > > test machine: 16 threads Intel(R) Core(TM) i7-13620H (Raptor Lake) with 32G memory
> > > > > 
> > > > > (please refer to attached dmesg/kmsg for entire log/backtrace)
> > > > > 
> > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > > > > the same patch/commit), kindly add following tags
> > > > > | Reported-by: kernel test robot <oliver.sang@intel.com>
> > > > > | Closes: https://lore.kernel.org/oe-lkp/202605111649.a8b30a62-lkp@intel.com
> > > > 
> > > > I was unable to run the landlock selftests myself, on my machines they are
> > > > failing at runtime with all kinds of colorful errors. Are the requirements
> > > > explained somewhere?
> > > 
> > > I'm curious about the errors you get.  They are standard kselftests that
> > > should work following this workflow:
> > > 
> > >   make TARGETS=landlock O=build kselftest-gen_tar
> > > 
> > > and then running ./build/kselftests/kselftest_install/run_kselftest.sh
> > > as root in a VM.  The required kernel configuration is listed in
> > > tools/testing/selftests/landlock/config
> > 
> > So there are two root issues I ran into:
> > 
> > 1) The tests can not be executed from virtiofs (as set up by virtme-ng):
> 
> Most filesystem tests initially set up tmpfs and then use it.
> 
> I'm using virtme-ng too, see the
> https://github.com/landlock-lsm/landlock-test-tools
> 
>  ARCH=x86_64 .../check-linux.sh build_light kselftest
> 
> > 
> >  #  RUN           audit.layers ...
> > # audit_test.c:52:layers:Expected 0 (0) <= self->audit_fd (-13)
> > # audit_test.c:61:layers:Failed to initialize audit: Permission denied
> > # layers: Test failed
> > #          FAIL  audit.layers
> > not ok 1 audit.layers
> > 
> > (The same for all other testcases)
> 
> It looks like the tests are not run with enough privileges.  Do you run
> them as root?  Does the kernel has the required config set?

Yes. The exact same setup works when executed from a tmpfs.

> > 2) $PWD needs to be the test binary directory for "./wait-pipe-sandbox" to work.
> 
> Yes.  run_kselftest.sh should handle that.

Fair enough. The selftests I used so far worked just fine when executed directly.
Maybe only I am using them this way. Some better diagnostics would have saved
me some time. Consider it a suggestion.

> > > To make it easier, we wrote a wrapper to test everything with UML:
> > > https://github.com/landlock-lsm/landlock-test-tools (see check-linux.sh)
> > > 
> > > > 
> > > > > # #  RUN           audit.tsync_override_log_subdomains_off ...
> > > > > # # audit_test.c:591:tsync_override_log_subdomains_off:Expected 0 (0) == matches_log_signal(_metadata, self->audit_fd, child_data.parent_pid, NULL) (-11)
> > > > 
> > > > This error number means "EAGAIN 11 Resource temporarily unavailable",
> > > > so it could be a temporary error.
> > > 
> > > Yes, the test is flaky under pressure.
> > > 
> > > > 
> > > > Can you reproduce this issue? Is it really dependent on my patch as
> > > > blamed above? If so, does the selftest rely on the previous, incorrect order?
> > > 
> > > I don't think it directly depends on your patch but it might be a side
> > > effect.  Anyway, I've been working on fixing this kind of issue and just
> > > sent a fix:
> > > https://lore.kernel.org/r/20260513105112.140137-2-mic@digikod.net
> > 
> > Thanks, unfortunately I can't validate that it will fix the issue at hand.
> 
> I pushed it to -next, we'll see but I'm pretty sure this is the issue.

Nice. I justed wanted to make clear that I won't be able to provide a Tested-by.


Thanks again,
Thomas