diff options
| -rw-r--r-- | Documentation/livepatch/callbacks.txt | 489 | ||||
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 22 | ||||
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/livepatch/Makefile | 15 | ||||
| -rw-r--r-- | lib/livepatch/test_klp_atomic_replace.c | 57 | ||||
| -rw-r--r-- | lib/livepatch/test_klp_callbacks_busy.c | 43 | ||||
| -rw-r--r-- | lib/livepatch/test_klp_callbacks_demo.c | 121 | ||||
| -rw-r--r-- | lib/livepatch/test_klp_callbacks_demo2.c | 93 | ||||
| -rw-r--r-- | lib/livepatch/test_klp_callbacks_mod.c | 24 | ||||
| -rw-r--r-- | lib/livepatch/test_klp_livepatch.c | 51 | ||||
| -rw-r--r-- | lib/livepatch/test_klp_shadow_vars.c | 236 | ||||
| -rw-r--r-- | tools/testing/selftests/Makefile | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/livepatch/Makefile | 8 | ||||
| -rw-r--r-- | tools/testing/selftests/livepatch/README | 43 | ||||
| -rw-r--r-- | tools/testing/selftests/livepatch/config | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/livepatch/functions.sh | 203 | ||||
| -rwxr-xr-x | tools/testing/selftests/livepatch/test-callbacks.sh | 587 | ||||
| -rwxr-xr-x | tools/testing/selftests/livepatch/test-livepatch.sh | 168 | ||||
| -rwxr-xr-x | tools/testing/selftests/livepatch/test-shadow-vars.sh | 60 |
20 files changed, 1740 insertions, 485 deletions
diff --git a/Documentation/livepatch/callbacks.txt b/Documentation/livepatch/callbacks.txt index c9776f48e458..182e31d4abce 100644 --- a/Documentation/livepatch/callbacks.txt +++ b/Documentation/livepatch/callbacks.txt @@ -118,488 +118,9 @@ similar change to their hw_features value. (Client functions of the value may need to be updated accordingly.) -Test cases -========== - -What follows is not an exhaustive test suite of every possible livepatch -pre/post-(un)patch combination, but a selection that demonstrates a few -important concepts. Each test case uses the kernel modules located in -the samples/livepatch/ and assumes that no livepatches are loaded at the -beginning of the test. - - -Test 1 ------- - -Test a combination of loading a kernel module and a livepatch that -patches a function in the first module. (Un)load the target module -before the livepatch module: - -- load target module -- load livepatch -- disable livepatch -- unload target module -- unload livepatch - -First load a target module: - - % insmod samples/livepatch/livepatch-callbacks-mod.ko - [ 34.475708] livepatch_callbacks_mod: livepatch_callbacks_mod_init - -On livepatch enable, before the livepatch transition starts, pre-patch -callbacks are executed for vmlinux and livepatch_callbacks_mod (those -klp_objects currently loaded). After klp_objects are patched according -to the klp_patch, their post-patch callbacks run and the transition -completes: - - % insmod samples/livepatch/livepatch-callbacks-demo.ko - [ 36.503719] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 36.504213] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 36.504238] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 36.504721] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state - [ 36.505849] livepatch: 'livepatch_callbacks_demo': starting patching transition - [ 37.727133] livepatch: 'livepatch_callbacks_demo': completing patching transition - [ 37.727232] livepatch_callbacks_demo: post_patch_callback: vmlinux - [ 37.727860] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state - [ 37.728792] livepatch: 'livepatch_callbacks_demo': patching complete - -Similarly, on livepatch disable, pre-patch callbacks run before the -unpatching transition starts. klp_objects are reverted, post-patch -callbacks execute and the transition completes: - - % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled - [ 38.510209] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition - [ 38.510234] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux - [ 38.510982] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state - [ 38.512209] livepatch: 'livepatch_callbacks_demo': starting unpatching transition - [ 39.711132] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 39.711210] livepatch_callbacks_demo: post_unpatch_callback: vmlinux - [ 39.711779] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state - [ 39.712735] livepatch: 'livepatch_callbacks_demo': unpatching complete - - % rmmod samples/livepatch/livepatch-callbacks-demo.ko - % rmmod samples/livepatch/livepatch-callbacks-mod.ko - [ 42.534183] livepatch_callbacks_mod: livepatch_callbacks_mod_exit - - -Test 2 ------- - -This test is similar to the previous test, but (un)load the livepatch -module before the target kernel module. This tests the livepatch core's -module_coming handler: - -- load livepatch -- load target module -- disable livepatch -- unload livepatch -- unload target module - - -On livepatch enable, only pre/post-patch callbacks are executed for -currently loaded klp_objects, in this case, vmlinux: - - % insmod samples/livepatch/livepatch-callbacks-demo.ko - [ 44.553328] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 44.553997] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 44.554049] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 44.554845] livepatch: 'livepatch_callbacks_demo': starting patching transition - [ 45.727128] livepatch: 'livepatch_callbacks_demo': completing patching transition - [ 45.727212] livepatch_callbacks_demo: post_patch_callback: vmlinux - [ 45.727961] livepatch: 'livepatch_callbacks_demo': patching complete - -When a targeted module is subsequently loaded, only its pre/post-patch -callbacks are executed: - - % insmod samples/livepatch/livepatch-callbacks-mod.ko - [ 46.560845] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod' - [ 46.561988] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init - [ 46.563452] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init - [ 46.565495] livepatch_callbacks_mod: livepatch_callbacks_mod_init - -On livepatch disable, all currently loaded klp_objects' (vmlinux and -livepatch_callbacks_mod) pre/post-unpatch callbacks are executed: - - % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled - [ 48.568885] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition - [ 48.568910] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux - [ 48.569441] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state - [ 48.570502] livepatch: 'livepatch_callbacks_demo': starting unpatching transition - [ 49.759091] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 49.759171] livepatch_callbacks_demo: post_unpatch_callback: vmlinux - [ 49.759742] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state - [ 49.760690] livepatch: 'livepatch_callbacks_demo': unpatching complete - - % rmmod samples/livepatch/livepatch-callbacks-demo.ko - % rmmod samples/livepatch/livepatch-callbacks-mod.ko - [ 52.592283] livepatch_callbacks_mod: livepatch_callbacks_mod_exit - - -Test 3 ------- - -Test loading the livepatch after a targeted kernel module, then unload -the kernel module before disabling the livepatch. This tests the -livepatch core's module_going handler: - -- load target module -- load livepatch -- unload target module -- disable livepatch -- unload livepatch - -First load a target module, then the livepatch: - - % insmod samples/livepatch/livepatch-callbacks-mod.ko - [ 54.607948] livepatch_callbacks_mod: livepatch_callbacks_mod_init - - % insmod samples/livepatch/livepatch-callbacks-demo.ko - [ 56.613919] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 56.614411] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 56.614436] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 56.614818] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state - [ 56.615656] livepatch: 'livepatch_callbacks_demo': starting patching transition - [ 57.759070] livepatch: 'livepatch_callbacks_demo': completing patching transition - [ 57.759147] livepatch_callbacks_demo: post_patch_callback: vmlinux - [ 57.759621] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_LIVE] Normal state - [ 57.760307] livepatch: 'livepatch_callbacks_demo': patching complete - -When a target module is unloaded, the livepatch is only reverted from -that klp_object (livepatch_callbacks_mod). As such, only its pre and -post-unpatch callbacks are executed when this occurs: - - % rmmod samples/livepatch/livepatch-callbacks-mod.ko - [ 58.623409] livepatch_callbacks_mod: livepatch_callbacks_mod_exit - [ 58.623903] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away - [ 58.624658] livepatch: reverting patch 'livepatch_callbacks_demo' on unloading module 'livepatch_callbacks_mod' - [ 58.625305] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away - -When the livepatch is disabled, pre and post-unpatch callbacks are run -for the remaining klp_object, vmlinux: - - % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled - [ 60.638420] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition - [ 60.638444] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux - [ 60.638996] livepatch: 'livepatch_callbacks_demo': starting unpatching transition - [ 61.727088] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 61.727165] livepatch_callbacks_demo: post_unpatch_callback: vmlinux - [ 61.727985] livepatch: 'livepatch_callbacks_demo': unpatching complete - - % rmmod samples/livepatch/livepatch-callbacks-demo.ko - - -Test 4 ------- - -This test is similar to the previous test, however the livepatch is -loaded first. This tests the livepatch core's module_coming and -module_going handlers: - -- load livepatch -- load target module -- unload target module -- disable livepatch -- unload livepatch - -First load the livepatch: - - % insmod samples/livepatch/livepatch-callbacks-demo.ko - [ 64.661552] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 64.662147] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 64.662175] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 64.662850] livepatch: 'livepatch_callbacks_demo': starting patching transition - [ 65.695056] livepatch: 'livepatch_callbacks_demo': completing patching transition - [ 65.695147] livepatch_callbacks_demo: post_patch_callback: vmlinux - [ 65.695561] livepatch: 'livepatch_callbacks_demo': patching complete - -When a targeted kernel module is subsequently loaded, only its -pre/post-patch callbacks are executed: - - % insmod samples/livepatch/livepatch-callbacks-mod.ko - [ 66.669196] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod' - [ 66.669882] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init - [ 66.670744] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init - [ 66.672873] livepatch_callbacks_mod: livepatch_callbacks_mod_init - -When the target module is unloaded, the livepatch is only reverted from -the livepatch_callbacks_mod klp_object. As such, only pre and -post-unpatch callbacks are executed when this occurs: - - % rmmod samples/livepatch/livepatch-callbacks-mod.ko - [ 68.680065] livepatch_callbacks_mod: livepatch_callbacks_mod_exit - [ 68.680688] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away - [ 68.681452] livepatch: reverting patch 'livepatch_callbacks_demo' on unloading module 'livepatch_callbacks_mod' - [ 68.682094] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away - - % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled - [ 70.689225] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition - [ 70.689256] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux - [ 70.689882] livepatch: 'livepatch_callbacks_demo': starting unpatching transition - [ 71.711080] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 71.711481] livepatch_callbacks_demo: post_unpatch_callback: vmlinux - [ 71.711988] livepatch: 'livepatch_callbacks_demo': unpatching complete - - % rmmod samples/livepatch/livepatch-callbacks-demo.ko - - -Test 5 ------- - -A simple test of loading a livepatch without one of its patch target -klp_objects ever loaded (livepatch_callbacks_mod): - -- load livepatch -- disable livepatch -- unload livepatch - -Load the livepatch: - - % insmod samples/livepatch/livepatch-callbacks-demo.ko - [ 74.711081] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 74.711595] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 74.711639] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 74.712272] livepatch: 'livepatch_callbacks_demo': starting patching transition - [ 75.743137] livepatch: 'livepatch_callbacks_demo': completing patching transition - [ 75.743219] livepatch_callbacks_demo: post_patch_callback: vmlinux - [ 75.743867] livepatch: 'livepatch_callbacks_demo': patching complete - -As expected, only pre/post-(un)patch handlers are executed for vmlinux: - - % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled - [ 76.716254] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition - [ 76.716278] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux - [ 76.716666] livepatch: 'livepatch_callbacks_demo': starting unpatching transition - [ 77.727089] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 77.727194] livepatch_callbacks_demo: post_unpatch_callback: vmlinux - [ 77.727907] livepatch: 'livepatch_callbacks_demo': unpatching complete +Other Examples +============== - % rmmod samples/livepatch/livepatch-callbacks-demo.ko - - -Test 6 ------- - -Test a scenario where a vmlinux pre-patch callback returns a non-zero -status (ie, failure): - -- load target module -- load livepatch -ENODEV -- unload target module - -First load a target module: - - % insmod samples/livepatch/livepatch-callbacks-mod.ko - [ 80.740520] livepatch_callbacks_mod: livepatch_callbacks_mod_init - -Load the livepatch module, setting its 'pre_patch_ret' value to -19 -(-ENODEV). When its vmlinux pre-patch callback executed, this status -code will propagate back to the module-loading subsystem. The result is -that the insmod command refuses to load the livepatch module: - - % insmod samples/livepatch/livepatch-callbacks-demo.ko pre_patch_ret=-19 - [ 82.747326] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 82.747743] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 82.747767] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 82.748237] livepatch: pre-patch callback failed for object 'vmlinux' - [ 82.748637] livepatch: failed to enable patch 'livepatch_callbacks_demo' - [ 82.749059] livepatch: 'livepatch_callbacks_demo': canceling transition, going to unpatch - [ 82.749060] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 82.749868] livepatch: 'livepatch_callbacks_demo': unpatching complete - [ 82.765809] insmod: ERROR: could not insert module samples/livepatch/livepatch-callbacks-demo.ko: No such device - - % rmmod samples/livepatch/livepatch-callbacks-mod.ko - [ 84.774238] livepatch_callbacks_mod: livepatch_callbacks_mod_exit - - -Test 7 ------- - -Similar to the previous test, setup a livepatch such that its vmlinux -pre-patch callback returns success. However, when a targeted kernel -module is later loaded, have the livepatch return a failing status code: - -- load livepatch -- setup -ENODEV -- load target module -- disable livepatch -- unload livepatch - -Load the livepatch, notice vmlinux pre-patch callback succeeds: - - % insmod samples/livepatch/livepatch-callbacks-demo.ko - [ 86.787845] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 86.788325] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 86.788427] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 86.788821] livepatch: 'livepatch_callbacks_demo': starting patching transition - [ 87.711069] livepatch: 'livepatch_callbacks_demo': completing patching transition - [ 87.711143] livepatch_callbacks_demo: post_patch_callback: vmlinux - [ 87.711886] livepatch: 'livepatch_callbacks_demo': patching complete - -Set a trap so subsequent pre-patch callbacks to this livepatch will -return -ENODEV: - - % echo -19 > /sys/module/livepatch_callbacks_demo/parameters/pre_patch_ret - -The livepatch pre-patch callback for subsequently loaded target modules -will return failure, so the module loader refuses to load the kernel -module. Notice that no post-patch or pre/post-unpatch callbacks are -executed for this klp_object: - - % insmod samples/livepatch/livepatch-callbacks-mod.ko - [ 90.796976] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod' - [ 90.797834] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init - [ 90.798900] livepatch: pre-patch callback failed for object 'livepatch_callbacks_mod' - [ 90.799652] livepatch: patch 'livepatch_callbacks_demo' failed for module 'livepatch_callbacks_mod', refusing to load module 'livepatch_callbacks_mod' - [ 90.819737] insmod: ERROR: could not insert module samples/livepatch/livepatch-callbacks-mod.ko: No such device - -However, pre/post-unpatch callbacks run for the vmlinux klp_object: - - % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled - [ 92.823547] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition - [ 92.823573] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux - [ 92.824331] livepatch: 'livepatch_callbacks_demo': starting unpatching transition - [ 93.727128] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 93.727327] livepatch_callbacks_demo: post_unpatch_callback: vmlinux - [ 93.727861] livepatch: 'livepatch_callbacks_demo': unpatching complete - - % rmmod samples/livepatch/livepatch-callbacks-demo.ko - - -Test 8 ------- - -Test loading multiple targeted kernel modules. This test-case is -mainly for comparing with the next test-case. - -- load busy target module (0s sleep), -- load livepatch -- load target module -- unload target module -- disable livepatch -- unload livepatch -- unload busy target module - - -Load a target "busy" kernel module which kicks off a worker function -that immediately exits: - - % insmod samples/livepatch/livepatch-callbacks-busymod.ko sleep_secs=0 - [ 96.910107] livepatch_callbacks_busymod: livepatch_callbacks_mod_init - [ 96.910600] livepatch_callbacks_busymod: busymod_work_func, sleeping 0 seconds ... - [ 96.913024] livepatch_callbacks_busymod: busymod_work_func exit - -Proceed with loading the livepatch and another ordinary target module, -notice that the post-patch callbacks are executed and the transition -completes quickly: - - % insmod samples/livepatch/livepatch-callbacks-demo.ko - [ 98.917892] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 98.918426] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 98.918453] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 98.918955] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state - [ 98.923835] livepatch: 'livepatch_callbacks_demo': starting patching transition - [ 99.743104] livepatch: 'livepatch_callbacks_demo': completing patching transition - [ 99.743156] livepatch_callbacks_demo: post_patch_callback: vmlinux - [ 99.743679] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state - [ 99.744616] livepatch: 'livepatch_callbacks_demo': patching complete - - % insmod samples/livepatch/livepatch-callbacks-mod.ko - [ 100.930955] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod' - [ 100.931668] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init - [ 100.932645] livepatch_callbacks_demo: post_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init - [ 100.934125] livepatch_callbacks_mod: livepatch_callbacks_mod_init - - % rmmod samples/livepatch/livepatch-callbacks-mod.ko - [ 102.942805] livepatch_callbacks_mod: livepatch_callbacks_mod_exit - [ 102.943640] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away - [ 102.944585] livepatch: reverting patch 'livepatch_callbacks_demo' on unloading module 'livepatch_callbacks_mod' - [ 102.945455] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away - - % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled - [ 104.953815] livepatch: 'livepatch_callbacks_demo': initializing unpatching transition - [ 104.953838] livepatch_callbacks_demo: pre_unpatch_callback: vmlinux - [ 104.954431] livepatch_callbacks_demo: pre_unpatch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state - [ 104.955426] livepatch: 'livepatch_callbacks_demo': starting unpatching transition - [ 106.719073] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 106.722633] livepatch_callbacks_demo: post_unpatch_callback: vmlinux - [ 106.723282] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state - [ 106.724279] livepatch: 'livepatch_callbacks_demo': unpatching complete - - % rmmod samples/livepatch/livepatch-callbacks-demo.ko - % rmmod samples/livepatch/livepatch-callbacks-busymod.ko - [ 108.975660] livepatch_callbacks_busymod: livepatch_callbacks_mod_exit - - -Test 9 ------- - -A similar test as the previous one, but force the "busy" kernel module -to do longer work. - -The livepatching core will refuse to patch a task that is currently -executing a to-be-patched function -- the consistency model stalls the -current patch transition until this safety-check is met. Test a -scenario where one of a livepatch's target klp_objects sits on such a -function for a long time. Meanwhile, load and unload other target -kernel modules while the livepatch transition is in progress. - -- load busy target module (30s sleep) -- load livepatch -- load target module -- unload target module -- disable livepatch -- unload livepatch -- unload busy target module - - -Load the "busy" kernel module, this time make it do 30 seconds worth of -work: - - % insmod samples/livepatch/livepatch-callbacks-busymod.ko sleep_secs=30 - [ 110.993362] livepatch_callbacks_busymod: livepatch_callbacks_mod_init - [ 110.994059] livepatch_callbacks_busymod: busymod_work_func, sleeping 30 seconds ... - -Meanwhile, the livepatch is loaded. Notice that the patch transition -does not complete as the targeted "busy" module is sitting on a -to-be-patched function: - - % insmod samples/livepatch/livepatch-callbacks-demo.ko - [ 113.000309] livepatch: enabling patch 'livepatch_callbacks_demo' - [ 113.000764] livepatch: 'livepatch_callbacks_demo': initializing patching transition - [ 113.000791] livepatch_callbacks_demo: pre_patch_callback: vmlinux - [ 113.001289] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state - [ 113.005208] livepatch: 'livepatch_callbacks_demo': starting patching transition - -Load a second target module (this one is an ordinary idle kernel -module). Note that *no* post-patch callbacks will be executed while the -livepatch is still in transition: - - % insmod samples/livepatch/livepatch-callbacks-mod.ko - [ 115.012740] livepatch: applying patch 'livepatch_callbacks_demo' to loading module 'livepatch_callbacks_mod' - [ 115.013406] livepatch_callbacks_demo: pre_patch_callback: livepatch_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init - [ 115.015315] livepatch_callbacks_mod: livepatch_callbacks_mod_init - -Request an unload of the simple kernel module. The patch is still -transitioning, so its pre-unpatch callbacks are skipped: - - % rmmod samples/livepatch/livepatch-callbacks-mod.ko - [ 117.022626] livepatch_callbacks_mod: livepatch_callbacks_mod_exit - [ 117.023376] livepatch: reverting patch 'livepatch_callbacks_demo' on unloading module 'livepatch_callbacks_mod' - [ 117.024533] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_mod -> [MODULE_STATE_GOING] Going away - -Finally the livepatch is disabled. Since none of the patch's -klp_object's post-patch callbacks executed, the remaining klp_object's -pre-unpatch callbacks are skipped: - - % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled - [ 119.035408] livepatch: 'livepatch_callbacks_demo': reversing transition from patching to unpatching - [ 119.035485] livepatch: 'livepatch_callbacks_demo': starting unpatching transition - [ 119.711166] livepatch: 'livepatch_callbacks_demo': completing unpatching transition - [ 119.714179] livepatch_callbacks_demo: post_unpatch_callback: vmlinux - [ 119.714653] livepatch_callbacks_demo: post_unpatch_callback: livepatch_callbacks_busymod -> [MODULE_STATE_LIVE] Normal state - [ 119.715437] livepatch: 'livepatch_callbacks_demo': unpatching complete - - % rmmod samples/livepatch/livepatch-callbacks-demo.ko - % rmmod samples/livepatch/livepatch-callbacks-busymod.ko - [ 141.279111] livepatch_callbacks_busymod: busymod_work_func exit - [ 141.279760] livepatch_callbacks_busymod: livepatch_callbacks_mod_exit +Sample livepatch modules demonstrating the callback API can be found in +samples/livepatch/ directory. These samples were modified for use in +kselftests and can be found in the lib/livepatch directory. diff --git a/MAINTAINERS b/MAINTAINERS index 39e75bbefc3d..b1c5cf166703 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8832,6 +8832,7 @@ F: arch/x86/kernel/livepatch.c F: Documentation/livepatch/ F: Documentation/ABI/testing/sysfs-kernel-livepatch F: samples/livepatch/ +F: tools/testing/selftests/livepatch/ L: live-patching@vger.kernel.org T: git git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching.git diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index d4df5b24d75e..0298eb8eaa4e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1991,6 +1991,27 @@ config TEST_MEMCAT_P If unsure, say N. +config TEST_LIVEPATCH + tristate "Test livepatching" + default n + depends on LIVEPATCH + depends on m + help + Test kernel livepatching features for correctness. The tests will + load test modules that will be livepatched in various scenarios. + + To run all the livepatching tests: + + make -C tools/testing/selftests TARGETS=livepatch run_tests + + Alternatively, individual tests may be invoked: + + tools/testing/selftests/livepatch/test-callbacks.sh + tools/testing/selftests/livepatch/test-livepatch.sh + tools/testing/selftests/livepatch/test-shadow-vars.sh + + If unsure, say N. + config TEST_OBJAGG tristate "Perform selftest on object aggreration manager" default n @@ -1999,7 +2020,6 @@ config TEST_OBJAGG Enable this option to test object aggregation manager on boot (or module load). - If unsure, say N. endif # RUNTIME_TESTING_MENU diff --git a/lib/Makefile b/lib/Makefile index e1b59da71418..a1cfa1975ca3 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -77,6 +77,8 @@ obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o +obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/ + ifeq ($(CONFIG_DEBUG_KOBJECT),y) CFLAGS_kobject.o += -DDEBUG CFLAGS_kobject_uevent.o += -DDEBUG diff --git a/lib/livepatch/Makefile b/lib/livepatch/Makefile new file mode 100644 index 000000000000..26900ddaef82 --- /dev/null +++ b/lib/livepatch/Makefile @@ -0,0 +1,15 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for livepatch test code. + +obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \ + test_klp_callbacks_demo.o \ + test_klp_callbacks_demo2.o \ + test_klp_callbacks_busy.o \ + test_klp_callbacks_mod.o \ + test_klp_livepatch.o \ + test_klp_shadow_vars.o + +# Target modules to be livepatched require CC_FLAGS_FTRACE +CFLAGS_test_klp_callbacks_busy.o += $(CC_FLAGS_FTRACE) +CFLAGS_test_klp_callbacks_mod.o += $(CC_FLAGS_FTRACE) diff --git a/lib/livepatch/test_klp_atomic_replace.c b/lib/livepatch/test_klp_atomic_replace.c new file mode 100644 index 000000000000..5af7093ca00c --- /dev/null +++ b/lib/livepatch/test_klp_atomic_replace.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com> + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/livepatch.h> + +static int replace; +module_param(replace, int, 0644); +MODULE_PARM_DESC(replace, "replace (default=0)"); + +#include <linux/seq_file.h> +static int livepatch_meminfo_proc_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%s: %s\n", THIS_MODULE->name, + "this has been live patched"); + return 0; +} + +static struct klp_func funcs[] = { + { + .old_name = "meminfo_proc_show", + .new_func = livepatch_meminfo_proc_show, + }, {} +}; + +static struct klp_object objs[] = { + { + /* name being NULL means vmlinux */ + .funcs = funcs, + }, {} +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, + /* set .replace in the init function below for demo purposes */ +}; + +static int test_klp_atomic_replace_init(void) +{ + patch.replace = replace; + return klp_enable_patch(&patch); +} + +static void test_klp_atomic_replace_exit(void) +{ +} + +module_init(test_klp_atomic_replace_init); +module_exit(test_klp_atomic_replace_exit); +MODULE_LICENSE("GPL"); +MODULE_INFO(livepatch, "Y"); +MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>"); +MODULE_DESCRIPTION("Livepatch test: atomic replace"); diff --git a/lib/livepatch/test_klp_callbacks_busy.c b/lib/livepatch/test_klp_callbacks_busy.c new file mode 100644 index 000000000000..40beddf8a0e2 --- /dev/null +++ b/lib/livepatch/test_klp_callbacks_busy.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com> + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/workqueue.h> +#include <linux/delay.h> + +static int sleep_secs; +module_param(sleep_secs, int, 0644); +MODULE_PARM_DESC(sleep_secs, "sleep_secs (default=0)"); + +static void busymod_work_func(struct work_struct *work); +static DECLARE_DELAYED_WORK(work, busymod_work_func); + +static void busymod_work_func(struct work_struct *work) +{ + pr_info("%s, sleeping %d seconds ...\n", __func__, sleep_secs); + msleep(sleep_secs * 1000); + pr_info("%s exit\n", __func__); +} + +static int test_klp_callbacks_busy_init(void) +{ + pr_info("%s\n", __func__); + schedule_delayed_work(&work, + msecs_to_jiffies(1000 * 0)); + return 0; +} + +static void test_klp_callbacks_busy_exit(void) +{ + cancel_delayed_work_sync(&work); + pr_info("%s\n", __func__); +} + +module_init(test_klp_callbacks_busy_init); +module_exit(test_klp_callbacks_busy_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>"); +MODULE_DESCRIPTION("Livepatch test: busy target module"); diff --git a/lib/livepatch/test_klp_callbacks_demo.c b/lib/livepatch/test_klp_callbacks_demo.c new file mode 100644 index 000000000000..3fd8fe1cd1cc --- /dev/null +++ b/lib/livepatch/test_klp_callbacks_demo.c @@ -0,0 +1,121 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com> + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/livepatch.h> + +static int pre_patch_ret; +module_param(pre_patch_ret, int, 0644); +MODULE_PARM_DESC(pre_patch_ret, "pre_patch_ret (default=0)"); + +static const char *const module_state[] = { + [MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state", + [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init", + [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away", + [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up", +}; + +static void callback_info(const char *callback, struct klp_object *obj) +{ + if (obj->mod) + pr_info("%s: %s -> %s\n", callback, obj->mod->name, + module_state[obj->mod->state]); + else + pr_info("%s: vmlinux\n", callback); +} + +/* Executed on object patching (ie, patch enablement) */ +static int pre_patch_callback(struct klp_object *obj) +{ + callback_info(__func__, obj); + return pre_patch_ret; +} + +/* Executed on object unpatching (ie, patch disablement) */ +static void post_patch_callback(struct klp_object *obj) +{ + callback_info(__func__, obj); +} + +/* Executed on object unpatching (ie, patch disablement) */ +static void pre_unpatch_callback(struct klp_object *obj) +{ + callback_info(__func__, obj); +} + +/* Executed on object unpatching (ie, patch disablement) */ +static void post_unpatch_callback(struct klp_object *obj) +{ + callback_info(__func__, obj); +} + +static void patched_work_func(struct work_struct *work) +{ + pr_info("%s\n", __func__); +} + +static struct klp_func no_funcs[] = { + {} +}; + +static struct klp_func busymod_funcs[] = { + { + .old_name = "busymod_work_func", + .new_func = patched_work_func, + }, {} +}; + +static struct klp_object objs[] = { + { + .name = NULL, /* vmlinux */ + .funcs = no_funcs, + .callbacks = { + .pre_patch = pre_patch_callback, + .post_patch = post_patch_callback, + .pre_unpatch = pre_unpatch_callback, + .post_unpatch = post_unpatch_callback, + }, + }, { + .name = "test_klp_callbacks_mod", + .funcs = no_funcs, + .callbacks = { + .pre_patch = pre_patch_callback, + .post_patch = post_patch_callback, + .pre_unpatch = pre_unpatch_callback, + .post_unpatch = post_unpatch_callback, + }, + }, { + .name = "test_klp_callbacks_busy", + .funcs = busymod_funcs, + .callbacks = { + .pre_patch = pre_patch_callback, |