linux-dev/kernel/kcsan/Makefile, branch master

Merge tag 'kcsan.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

2022-01-11T17:51:26Z

Pull KCSAN updates from Paul McKenney: "This provides KCSAN fixes and also the ability to take memory barriers into account for weakly-ordered systems. This last can increase the probability of detecting certain types of data races" * tag 'kcsan.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (29 commits) kcsan: Only test clear_bit_unlock_is_negative_byte if arch defines it kcsan: Avoid nested contexts reading inconsistent reorder_access kcsan: Turn barrier instrumentation into macros kcsan: Make barrier tests compatible with lockdep kcsan: Support WEAK_MEMORY with Clang where no objtool support exists compiler_attributes.h: Add __disable_sanitizer_instrumentation objtool, kcsan: Remove memory barrier instrumentation from noinstr objtool, kcsan: Add memory barrier instrumentation to whitelist sched, kcsan: Enable memory barrier instrumentation mm, kcsan: Enable barrier instrumentation x86/qspinlock, kcsan: Instrument barrier of pv_queued_spin_unlock() x86/barriers, kcsan: Use generic instrumentation for non-smp barriers asm-generic/bitops, kcsan: Add instrumentation for barriers locking/atomics, kcsan: Add instrumentation for barriers locking/barriers, kcsan: Support generic instrumentation locking/barriers, kcsan: Add instrumentation for barriers kcsan: selftest: Add test case to check memory barrier instrumentation kcsan: Ignore GCC 11+ warnings about TSan runtime support kcsan: test: Add test cases for memory barrier instrumentation kcsan: test: Match reordered or normal accesses ...

arm64: Enable KCSAN

2021-12-14T18:54:34Z

This patch enables KCSAN for arm64, with updates to build rules to not use KCSAN for several incompatible compilation units. Recent GCC version(at least GCC10) made outline-atomics as the default option(unlike Clang), which will cause linker errors for kernel/kcsan/core.o. Disables the out-of-line atomics by no-outline-atomics to fix the linker errors. Meanwhile, as Mark said[1], some latent issues are needed to be fixed which isn't just a KCSAN problem, we make the KCSAN depends on EXPERT for now. Tested selftest and kcsan_test(built with GCC11 and Clang 13), and all passed. [1] https://lkml.kernel.org/r/YadiUPpJ0gADbiHQ@FVFF77S0Q05N Acked-by: Marco Elver # kernel/kcsan Tested-by: Joey Gouly Signed-off-by: Kefeng Wang Link: https://lore.kernel.org/r/20211211131734.126874-1-wangkefeng.wang@huawei.com [catalin.marinas@arm.com: added comment to justify EXPERT] Signed-off-by: Catalin Marinas

kcsan: selftest: Add test case to check memory barrier instrumentation

2021-12-10T00:42:27Z

Memory barrier instrumentation is crucial to avoid false positives. To avoid surprises, run a simple test case in the boot-time selftest to ensure memory barriers are still instrumented correctly. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Make test follow KUnit style recommendations

2021-03-08T22:27:43Z

Per recently added KUnit style recommendations at Documentation/dev-tools/kunit/style.rst, make the following changes to the KCSAN test: 1. Rename 'kcsan-test.c' to 'kcsan_test.c'. 2. Rename suite name 'kcsan-test' to 'kcsan'. 3. Rename CONFIG_KCSAN_TEST to CONFIG_KCSAN_KUNIT_TEST and default to KUNIT_ALL_TESTS. Reviewed-by: David Gow Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Disable branch tracing in core runtime

2020-06-29T19:04:48Z

Disable branch tracing in core KCSAN runtime if branches are being traced (TRACE_BRANCH_PROFILING). This it to avoid its performance impact, but also avoid recursion in case KCSAN is enabled for the branch tracing runtime. The latter had already been a problem for KASAN: https://lore.kernel.org/lkml/CANpmjNOeXmD5E3O50Z3MjkiuCYaYOPyi+1rq=GZvEKwBvLR0Ug@mail.gmail.com/ Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Simplify compiler flags

2020-06-29T19:04:48Z

Simplify the set of compiler flags for the runtime by removing cc-option from -fno-stack-protector, because all supported compilers support it. This saves us one compiler invocation during build. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Rename test.c to selftest.c

2020-06-29T19:04:48Z

Rename 'test.c' to 'selftest.c' to better reflect its purpose (Kconfig variable and code inside already match this). This is to avoid confusion with the test suite module in 'kcsan-test.c'. No functional change. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Add test suite

2020-06-29T19:04:48Z

This adds KCSAN test focusing on behaviour of the integrated runtime. Tests various race scenarios, and verifies the reports generated to console. Makes use of KUnit for test organization, and the Torture framework for test thread control. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan, trace: Make KCSAN compatible with tracing

2020-03-21T08:44:41Z

Previously the system would lock up if ftrace was enabled together with KCSAN. This is due to recursion on reporting if the tracer code is instrumented with KCSAN. To avoid this for all types of tracing, disable KCSAN instrumentation for all of kernel/trace. Furthermore, since KCSAN relies on udelay() to introduce delay, we have to disable ftrace for udelay() (currently done for x86) in case KCSAN is used together with lockdep and ftrace. The reason is that it may corrupt lockdep IRQ flags tracing state due to a peculiar case of recursion (details in Makefile comment). Reported-by: Qian Cai Tested-by: Qian Cai Acked-by: Steven Rostedt (VMware) Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney Signed-off-by: Ingo Molnar

kcsan, ubsan: Make KCSAN+UBSAN work together

2020-01-07T15:47:23Z

Context: http://lkml.kernel.org/r/fb7e25d8-aba4-3dcf-7761-cb7ecb3ebb71@infradead.org Reported-by: Randy Dunlap Signed-off-by: Marco Elver Acked-by: Randy Dunlap # build-tested Signed-off-by: Paul E. McKenney