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2022-06-15selftests/livepatch: better synchronize test_klp_callbacks_busyJoe Lawrence1-0/+8
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: 547840bd5ae5 ("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
2020-08-09Merge tag 'kbuild-v5.9' of ↵Linus Torvalds1-4/+0
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - run the checker (e.g. sparse) after the compiler - remove unneeded cc-option tests for old compiler flags - fix tar-pkg to install dtbs - introduce ccflags-remove-y and asflags-remove-y syntax - allow to trace functions in sub-directories of lib/ - introduce hostprogs-always-y and userprogs-always-y syntax - various Makefile cleanups * tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled kbuild: introduce hostprogs-always-y and userprogs-always-y kbuild: sort hostprogs before passing it to ifneq kbuild: move host .so build rules to scripts/gcc-plugins/Makefile kbuild: Replace HTTP links with HTTPS ones kbuild: trace functions in subdirectories of lib/ kbuild: introduce ccflags-remove-y and asflags-remove-y kbuild: do not export LDFLAGS_vmlinux kbuild: always create directories of targets powerpc/boot: add DTB to 'targets' kbuild: buildtar: add dtbs support kbuild: remove cc-option test of -ffreestanding kbuild: remove cc-option test of -fno-stack-protector Revert "kbuild: Create directory for target DTB" kbuild: run the checker after the compiler
2020-08-10kbuild: trace functions in subdirectories of lib/Masahiro Yamada1-6/+0
ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE) exists here in sub-directories of lib/ to keep the behavior of commit 2464a609ded0 ("ftrace: do not trace library functions"). Since that commit, not only the objects in lib/ but also the ones in the sub-directories are excluded from ftrace (although the commit description did not explicitly mention this). However, most of library functions in sub-directories are not so hot. Re-add them to ftrace. Going forward, only the objects right under lib/ will be excluded. Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-08-10kbuild: introduce ccflags-remove-y and asflags-remove-yMasahiro Yamada1-0/+2
CFLAGS_REMOVE_<file>.o filters out flags when compiling a particular object, but there is no convenient way to do that for every object in a directory. Add ccflags-remove-y and asflags-remove-y to make it easily. Use ccflags-remove-y to clean up some Makefiles. The add/remove order works as follows: [1] KBUILD_CFLAGS specifies compiler flags used globally [2] ccflags-y adds compiler flags for all objects in the current Makefile [3] ccflags-remove-y removes compiler flags for all objects in the current Makefile (New feature) [4] CFLAGS_<file> adds compiler flags per file. [5] CFLAGS_REMOVE_<file> removes compiler flags per file. Having [3] before [4] allows us to remove flags from most (but not all) objects in the current Makefile. For example, kernel/trace/Makefile removes $(CC_FLAGS_FTRACE) from all objects in the directory, then adds it back to trace_selftest_dynamic.o and CFLAGS_trace_kprobe_selftest.o The same applies to lib/livepatch/Makefile. Please note ccflags-remove-y has no effect to the sub-directories. In contrast, the previous notation got rid of compiler flags also from all the sub-directories. The following are not affected because they have no sub-directories: arch/arm/boot/compressed/ arch/powerpc/xmon/ arch/sh/ kernel/trace/ However, lib/ has several sub-directories. To keep the behavior, I added ccflags-remove-y to all Makefiles in subdirectories of lib/, except the following: lib/vdso/Makefile - Kbuild does not descend into this Makefile lib/raid/test/Makefile - This is not used for the kernel build I think commit 2464a609ded0 ("ftrace: do not trace library functions") excluded too much. In the next commit, I will remove ccflags-remove-y from the sub-directories of lib/. Suggested-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by: Brendan Higgins <brendanhiggins@google.com> (KUnit) Tested-by: Anders Roxell <anders.roxell@linaro.org>
2020-06-08selftests/livepatch: fix mem leaks in test-klp-shadow-varsYannick Cote1-12/+31
In some cases, when an error occurs during testing and the main test routine returns, a memory leak occurs via leaving previously registered shadow variables allocated in the kernel as well as shadow_ptr list elements. From now on, in case of error, remove all allocated shadow variables and shadow_ptr struct elements. Signed-off-by: Yannick Cote <ycote@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20200603182058.109470-5-ycote@redhat.com
2020-06-08selftests/livepatch: more verification in test-klp-shadow-varsYannick Cote1-100/+92
This change makes the test feel more familiar with narrowing to a typical usage by operating on a number of identical structure instances and populating the same two new shadow variables symmetrically while keeping the same testing and verification criteria for the extra variables. Signed-off-by: Yannick Cote <ycote@redhat.com> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20200603182058.109470-4-ycote@redhat.com
2020-06-08selftests/livepatch: rework test-klp-shadow-varsYannick Cote1-44/+57
The initial idea was to make a change to please cppcheck and remove void pointer arithmetics found a few times: portability: 'obj' is of type 'void *'. When using void pointers in calculations, the behaviour is undefined. [arithOperationsOnVoidPointer] The rest of the changes are to help make the test read as an example while continuing to verify the shadow variable code. The logic of the test is unchanged but restructured to use descriptive names. Signed-off-by: Yannick Cote <ycote@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20200603182058.109470-3-ycote@redhat.com
2020-06-08selftests/livepatch: simplify test-klp-callbacks busy target testsJoe Lawrence1-9/+28
The test-klp-callbacks script includes a few tests which rely on kernel task timings that may not always execute as expected under system load. These may generate out of sequence kernel log messages that result in test failure. Instead of using sleep timing windows to orchestrate these tests, add a block_transition module parameter to communicate the test purpose and utilize flush_queue() to serialize the test module's task output. Signed-off-by: Joe Lawrence <joe.lawrence@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/20200603182058.109470-2-ycote@redhat.com
2020-01-17livepatch/samples/selftest: Use klp_shadow_alloc() API correctlyPetr Mladek1-22/+30
The commit e91c2518a5d22a ("livepatch: Initialize shadow variables safely by a custom callback") leads to the following static checker warning: samples/livepatch/livepatch-shadow-fix1.c:86 livepatch_fix1_dummy_alloc() error: 'klp_shadow_alloc()' 'leak' too small (4 vs 8) It is because klp_shadow_alloc() is used a wrong way: int *leak; shadow_leak = klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL, shadow_leak_ctor, leak); The code is supposed to store the "leak" pointer into the shadow variable. 3rd parameter correctly passes size of the data (size of pointer). But the 5th parameter is wrong. It should pass pointer to the data (pointer to the pointer) but it passes the pointer directly. It works because shadow_leak_ctor() handle "ctor_data" as the data instead of pointer to the data. But it is semantically wrong and confusing. The same problem is also in the module used by selftests. In this case, "pvX" variables are introduced. They represent the data stored in the shadow variables. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-01-17livepatch/selftest: Clean up shadow variable names and typePetr Mladek1-41/+52
The shadow variable selftest is quite tricky. Especially it is problematic to understand what values are stored, returned, and printed. Make it easier to understand by using "int *var, **sv" variables consistently everywhere instead of the generic "void *", "ret", and "ctor_data". Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2019-11-01livepatch: Selftests of the API for tracking system state changesPetr Mladek4-1/+362
Four selftests for the new API. Link: http://lkml.kernel.org/r/20191030154313.13263-6-pmladek@suse.com To: Jiri Kosina <jikos@kernel.org> Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Cc: Nicolai Stange <nstange@suse.de> Cc: live-patching@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-02-06livepatch: Proper error handling in the shadow variables selftestPetr Mladek1-0/+22
Add proper error handling when allocating or getting shadow variables in the selftest. It prevents an invalid pointer access in some situations. It shows the good programming practice in the others. The error codes are just the best guess and specific for this particular test. In general, klp_shadow_alloc() returns NULL also when the given shadow variable has already been allocated. In addition, both klp_shadow_alloc() and klp_shadow_get_or_alloc() might fail from other reasons when the constructor fails. Note, that the error code is not really important even in the real life. The use of shadow variables should be transparent for the original livepatched code. Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-02-06livepatch: return -ENOMEM on ptr_id() allocation failureJoe Lawrence1-1/+1
Fixes the following smatch warning: lib/livepatch/test_klp_shadow_vars.c:47 ptr_id() warn: returning -1 instead of -ENOMEM is sloppy Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-01-11selftests/livepatch: introduce testsJoe Lawrence8-0/+640
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>