acrn-kernel/lib/livepatch
Joe Lawrence 55eb9a6c8b selftests/livepatch: better synchronize test_klp_callbacks_busy
The test_klp_callbacks_busy module conditionally blocks a future
livepatch transition by busy waiting inside its workqueue function,
busymod_work_func().  After scheduling this work, a test livepatch is
loaded, introducing the transition under test.

Both events are marked in the kernel log for later verification, but
there is no synchronization to ensure that busymod_work_func() logs its
function entry message before subsequent selftest commands log their own
messages.  This can lead to a rare test failure due to unexpected
ordering like:

  --- expected
  +++ result
  @@ -1,7 +1,7 @@
   % modprobe test_klp_callbacks_busy block_transition=Y
   test_klp_callbacks_busy: test_klp_callbacks_busy_init
  -test_klp_callbacks_busy: busymod_work_func enter
   % modprobe test_klp_callbacks_demo
  +test_klp_callbacks_busy: busymod_work_func enter
   livepatch: enabling patch 'test_klp_callbacks_demo'
   livepatch: 'test_klp_callbacks_demo': initializing patching transition
   test_klp_callbacks_demo: pre_patch_callback: vmlinux

Force the module init function to wait until busymod_work_func() has
started (and logged its message), before exiting to the next selftest
steps.

Fixes: 547840bd5a ("selftests/livepatch: simplify test-klp-callbacks busy target tests")
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220602203233.979681-1-joe.lawrence@redhat.com
2022-06-15 10:29:10 +02:00
..
Makefile kbuild: trace functions in subdirectories of lib/ 2020-08-10 01:32:59 +09:00
test_klp_atomic_replace.c
test_klp_callbacks_busy.c selftests/livepatch: better synchronize test_klp_callbacks_busy 2022-06-15 10:29:10 +02:00
test_klp_callbacks_demo.c
test_klp_callbacks_demo2.c selftests/livepatch: introduce tests 2019-01-11 20:51:24 +01:00
test_klp_callbacks_mod.c
test_klp_livepatch.c
test_klp_shadow_vars.c selftests/livepatch: fix mem leaks in test-klp-shadow-vars 2020-06-08 10:55:10 +02:00
test_klp_state.c livepatch: Selftests of the API for tracking system state changes 2019-11-01 13:08:29 +01:00
test_klp_state2.c livepatch: Selftests of the API for tracking system state changes 2019-11-01 13:08:29 +01:00
test_klp_state3.c livepatch: Selftests of the API for tracking system state changes 2019-11-01 13:08:29 +01:00