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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> |
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| .. | ||
| config | ||
| functions.sh | ||
| Makefile | ||
| README | ||
| settings | ||
| test-callbacks.sh | ||
| test-ftrace.sh | ||
| test-livepatch.sh | ||
| test-shadow-vars.sh | ||
| test-state.sh | ||
| test-sysfs.sh | ||
==================== Livepatch Self Tests ==================== This is a small set of sanity tests for the kernel livepatching. The test suite loads and unloads several test kernel modules to verify livepatch behavior. Debug information is logged to the kernel's message buffer and parsed for expected messages. (Note: the tests will compare the message buffer for only the duration of each individual test.) Config ------ Set these config options and their prerequisites: CONFIG_LIVEPATCH=y CONFIG_TEST_LIVEPATCH=m Running the tests ----------------- Test kernel modules are built as part of lib/ (make modules) and need to be installed (make modules_install) as the test scripts will modprobe them. To run the livepatch selftests, from the top of the kernel source tree: % make -C tools/testing/selftests TARGETS=livepatch run_tests Adding tests ------------ See the common functions.sh file for the existing collection of utility functions, most importantly setup_config(), start_test() and check_result(). The latter function greps the kernel's ring buffer for "livepatch:" and "test_klp" strings, so tests be sure to include one of those strings for result comparison. Other utility functions include general module loading and livepatch loading helpers (waiting for patch transitions, sysfs entries, etc.)