linux-toradex.git/kernel/kcsan/Makefile, branch v7.0-rc6

kcsan: Enable context analysis

2026-01-05T15:43:35+00:00

Enable context analysis for the KCSAN subsystem.

Signed-off-by: Marco Elver 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20251219154418.3592607-31-elver@google.com

kcsan: avoid passing -g for test

2023-03-24T00:18:35+00:00

Nathan reported that when building with GNU as and a version of clang that
defaults to DWARF5, the assembler will complain with:

  Error: non-constant .uleb128 is not supported

This is because `-g` defaults to the compiler debug info default. If the
assembler does not support some of the directives used, the above errors
occur. To fix, remove the explicit passing of `-g`.

All the test wants is that stack traces print valid function names, and
debug info is not required for that. (I currently cannot recall why I
added the explicit `-g`.)

Link: https://lkml.kernel.org/r/20230316224705.709984-2-elver@google.com
Fixes: 1fe84fd4a402 ("kcsan: Add test suite")
Signed-off-by: Marco Elver 
Reported-by: Nathan Chancellor 
Cc: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: 
Signed-off-by: Andrew Morton

kernel: kcsan: kcsan_test: build without structleak plugin

2022-12-12T03:30:18+00:00

Building kcsan_test with structleak plugin enabled makes the stack frame
size to grow.

kernel/kcsan/kcsan_test.c:704:1: error: the frame size of 3296 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]

Turn off the structleak plugin checks for kcsan_test.

Link: https://lkml.kernel.org/r/20221128104358.2660634-1-anders.roxell@linaro.org
Signed-off-by: Anders Roxell 
Suggested-by: Arnd Bergmann 
Acked-by: Marco Elver 
Cc: Arnd Bergmann 
Cc: David Gow 
Cc: Jason A. Donenfeld 
Cc: Kees Cook 
Signed-off-by: Andrew Morton

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

2022-01-11T17:51:26+00:00

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

2021-12-14T18:54:34+00:00

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

2021-12-10T00:42:27+00:00

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

2021-03-08T22:27:43+00:00

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

2020-06-29T19:04:48+00:00

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

2020-06-29T19:04:48+00:00

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

2020-06-29T19:04:48+00:00

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