selftests: livepatch: Avoid running the tests if kernel-devel is missing

By checking if KDIR is a valid directory we can safely skip the tests if
kernel-devel isn't installed (default value of KDIR), or if KDIR
variable passed doesn't exists.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402191417.XULH88Ct-lkp@intel.com/
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

livepatch: Move tests from lib/livepatch to selftests/livepatch

The modules are being moved from lib/livepatch to
tools/testing/selftests/livepatch/test_modules.

This code moving will allow writing more complex tests, like for example an
userspace C code that will call a livepatched kernel function.

The modules are now built as out-of-tree
modules, but being part of the kernel source means they will be maintained.

Another advantage of the code moving is to be able to easily change,
debug and rebuild the tests by running make on the selftests/livepatch
directory, which is not currently possible since the modules on
lib/livepatch are build and installed using the "modules" target.

The current approach also keeps the ability to execute the tests manually
by executing the scripts inside selftests/livepatch directory, as it's
currently supported. If the modules are modified, they needed to be
rebuilt before running the scripts though.

The modules are built before running the selftests when using the
kselftest invocations:

make kselftest TARGETS=livepatch
or
make -C tools/testing/selftests/livepatch run_tests

Having the modules being built as out-of-modules requires changing the
currently used 'modprobe' by 'insmod' and adapt the test scripts that
check for the kernel message buffer.

Now it is possible to only compile the modules by running:

make -C tools/testing/selftests/livepatch/

This way the test modules and other test program can be built in order
to be packaged if so desired.

As there aren't any modules being built on lib/livepatch, remove the
TEST_LIVEPATCH Kconfig and it's references.

Note: "make gen_tar" packages the pre-built binaries into the tarball.
It means that it will store the test modules pre-built for
the kernel running on the build host.

Note that these modules need not binary compatible with
the kernel built from the same sources. But the same
is true for other packaged selftest binaries.

The entire kernel sources are needed for rebuilding
the selftests on another system.

Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/livepatch: fix and refactor new dmesg message code

The livepatching kselftests rely on comparing expected vs. observed
dmesg output. After each test, new dmesg entries are determined by the
'comm' utility comparing a saved, pre-test copy of dmesg to post-test
dmesg output.

Alexander reports that the 'comm --nocheck-order -13' invocation used by
the tests can be confused when dmesg entry timestamps vary in magnitude
(ie, "[ 98.820331]" vs. "[ 100.031067]"), in which case, additional
messages are reported as new. The unexpected entries then spoil the
test results.

Instead of relying on 'comm' or 'diff' to determine new testing dmesg
entries, refactor the code:

- pre-test : log a unique canary dmesg entry
- test : run tests, log messages
- post-test : filter dmesg starting from pre-test message

Reported-by: Alexander Gordeev <agordeev@linux.ibm.com>
Closes: https://lore.kernel.org/live-patching/ZYAimyPYhxVA9wKg@li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com/
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Tested-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/livepatch: add sysfs test

Add a test for livepatch sysfs entries.

Signed-off-by: Song Liu <song@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220902205208.3117798-3-song@kernel.org

selftests/livepatch: normalize sysctl error message

The livepatch kselftests rely on comparing expected and actual output
from such commands as sysctl. A recent commit in procps-ng v4.0.0 [1]
changed sysctl's output to emit key pathnames like:

sysctl: setting key "/proc/sys/kernel/ftrace_enabled": Device or resource busy

versus previous dotted output:

sysctl: setting key "kernel.ftrace_enabled": Device or resource busy

The modification in output was later reverted [2], but since the change
has been tagged in procps-ng v4.0.0, update the livepatch kselftest to
handle either case.

[1] https://gitlab.com/procps-ng/procps/-/commit/6389deca5bf667f5fab5912acde78ba8e0febbc7
[2] https://gitlab.com/procps-ng/procps/-/commit/b159c198c9160a8eb13254e2b631d0035b9b542c

Reported-by: Dennis(Zhuoheng) Li <denli@redhat.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220811212138.182575-1-joe.lawrence@redhat.com

livepatch: Skip livepatch tests if ftrace cannot be configured

livepatch has a set of selftests that are used to validate the behavior of
the livepatching subsystem. One of the testcases in the livepatch
testsuite is test-ftrace.sh, which among other things, validates that
livepatching gracefully fails when ftrace is disabled. In the event that
ftrace cannot be disabled using 'sysctl kernel.ftrace_enabled=0', the test
will fail later due to it unexpectedly successfully loading the
test_klp_livepatch module.

While the livepatch selftests are careful to remove any of the livepatch
test modules between testcases to avoid this situation, ftrace may still
fail to be disabled if another trace is active on the system that was
enabled with FTRACE_OPS_FL_PERMANENT. For example, any active BPF programs
that use trampolines will cause this test to fail due to the trampoline
being implemented with register_ftrace_direct(). The following is an
example of such a trace:

tcp_drop (1) R I D tramp: ftrace_regs_caller+0x0/0x58
(call_direct_funcs+0x0/0x30)
direct-->bpf_trampoline_6442550536_0+0x0/0x1000

In order to make the test more resilient to system state that is out of its
control, this patch updates set_ftrace_enabled() to detect sysctl failures,
and skip the testrun when appropriate.

Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220216161100.3243100-1-void@manifault.com

selftests/livepatch: Do not check order when using "comm" for dmesg checking

check_result() uses "comm" to check expected results of selftests output
in dmesg. Everything works fine if timestamps in dmesg are unique. If
not, like in this example

[ 86.844422] test_klp_callbacks_demo: pre_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_LIVE] Normal state
[ 86.844422] livepatch: 'test_klp_callbacks_demo': starting unpatching transition

, "comm" fails with "comm: file 2 is not in sorted order". Suppress the
order checking with --nocheck-order option.

Fixes: 2f3f651f3756 ("selftests/livepatch: Use "comm" instead of "diff" for dmesg")
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

selftests/livepatch: adopt to newer sysctl error format

With procfs v3.3.16, the sysctl command doesn't print the set key and
value on error. This change breaks livepatch selftest test-ftrace.sh,
that tests the interaction of sysctl ftrace_enabled:

Make it work with all sysctl versions using '-q' option.

Explicitly print the final status on success so that it can be verified
in the log. The error message is enough on failure.

Reported-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20200714091030.1611-1-pmladek@suse.com

selftests/livepatch: Use "comm" instead of "diff" for dmesg

BusyBox diff doesn't support the GNU diff '--LTYPE-line-format' options
that were used in the selftests to filter older kernel log messages from
dmesg output.

Use "comm" which is more available in smaller boot environments.

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Yannick Cote <ycote@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200710183745.19730-1-joe.lawrence@redhat.com

selftests/livepatch: add test delimiter to dmesg

Make it bit easier to parse the kernel logs during the selftests by
adding a "===== TEST: $test =====" delimiter when each individual test
begins.

Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Yannick Cote <ycote@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200618181040.21132-4-joe.lawrence@redhat.com

selftests/livepatch: refine dmesg 'taints' in dmesg comparison

The livepatch selftests currently grep on "taints" to filter out
"tainting kernel with TAINT_LIVEPATCH" messages which may be logged when
loading livepatch modules.

Further filter the log to drop "loading out-of-tree module taints
kernel" in the rare case the klp_test modules have been built
out-of-tree.

Look for the longer "taints kernel" or "tainting kernel" strings to
avoid inadvertent partial matching.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Yannick Cote <ycote@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200618181040.21132-3-joe.lawrence@redhat.com

selftests/livepatch: Don't clear dmesg when running tests

Inspired by commit f131d9edc29d ("selftests/lkdtm: Don't clear dmesg
when running tests"), keep a reference dmesg copy when beginning each
test. This way check_result() can compare against the initial copy
rather than relying upon an empty log.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Yannick Cote <ycote@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200618181040.21132-2-joe.lawrence@redhat.com

selftests/livepatch: Remove unused local variable in set_ftrace_enabled()

set_ftrace_enabled() contains unused local variable "sysctl". Remove it.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests: livepatch: Fix it to do root uid check and skip

livepatch test configures the system and debug environment to run
tests. Some of these actions fail without root access and test
dumps several permission denied messages before it exits.

Fix test-state.sh to call setup_config instead of set_dynamic_debug
as suggested by Petr Mladek <pmladek@suse.com>

Fix it to check root uid and exit with skip code instead.

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/livepatch: Test interaction with ftrace_enabled

Since livepatching depends upon ftrace handlers to implement "patched"
code functionality, verify that the ftrace_enabled sysctl value
interacts with livepatch registration as expected. At the same time,
ensure that ftrace_enabled is set and part of the test environment
configuration that is saved and restored when running the selftests.

Link: http://lkml.kernel.org/r/20191016113316.13415-4-mbenes@suse.cz

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

selftests/livepatch: Make dynamic debug setup and restore generic

Livepatch selftests currently save the current dynamic debug config and
tweak it for the selftests. The config is restored at the end. Make the
infrastructure generic, so that more variables can be saved and
restored.

Link: http://lkml.kernel.org/r/20191016113316.13415-3-mbenes@suse.cz

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

selftests/livepatch: push and pop dynamic debug config

The livepatching self-tests tweak the dynamic debug config to verify
the kernel log during the tests. Enhance set_dynamic_debug() so that
the config changes are restored when the script exits.

Note this functionality needs to keep in sync with:
- dynamic_debug input/output formatting
- functions affected by set_dynamic_debug()

For example, push_dynamic_debug() transforms:
kernel/livepatch/transition.c:530 [livepatch]klp_init_transition =_ "'%s': initializing %s transition\012"
to the following:
file kernel/livepatch/transition.c line 530 =_

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/livepatch: add test skip handling

Add a skip() message function that stops the test, logs an explanation,
and sets the "skip" return code (4).

Before loading a livepatch self-test kernel module, first verify that
we've built and installed it by running a 'modprobe --dry-run'. This
should catch a few environment issues, including !CONFIG_LIVEPATCH and
!CONFIG_TEST_LIVEPATCH. In these cases, exit gracefully with the new
skip() function.

Reported-by: Jiri Benc <jbenc@redhat.com>
Suggested-by: Shuah Khan <shuah@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

livepatch/selftests: use "$@" to preserve argument list

The livepatch selftest functions.sh library uses "$*" and an
intermediate variable to extract and then pass arguments from function
to function call. The effect of this combination is that the argument
list is flattened into a single argument. Sometimes this is benign, but
in cases like __load_mod(), the modprobe invocation will interpret all
the module parameters as a single parameter.

Drop the intermediate variable and use the "$@" special parameter as
described in the bash manual.

Link: https://www.gnu.org/software/bash/manual/bash.html#Special-Parameters
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Petr Mladek <pmladek@suse.com>

selftests/livepatch: introduce tests

Add a few livepatch modules and simple target modules that the included
regression suite can run tests against:

- basic livepatching (multiple patches, atomic replace)
- pre/post (un)patch callbacks
- shadow variable API

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Tested-by: Miroslav Benes <mbenes@suse.cz>
Tested-by: Alice Ferrazzi <alice.ferrazzi@gmail.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>