kcsan: avoid passing -g for test

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 n

kcsan: avoid passing -g for test

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/[email protected]
Fixes: 1fe84fd4a402 ("kcsan: Add test suite")
Signed-off-by: Marco Elver <[email protected]>
Reported-by: Nathan Chancellor <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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kernel: kcsan: kcsan_test: build without structleak plugin

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

kernel/kcsan/kcsan_test.c:704:1: error: the frame s

kernel: kcsan: kcsan_test: build without structleak plugin

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/[email protected]
Signed-off-by: Anders Roxell <[email protected]>
Suggested-by: Arnd Bergmann <[email protected]>
Acked-by: Marco Elver <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: David Gow <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Kees Cook <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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arm64: Enable KCSAN

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-atom

arm64: Enable KCSAN

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 <[email protected]> # kernel/kcsan
Tested-by: Joey Gouly <[email protected]>
Signed-off-by: Kefeng Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[[email protected]: added comment to justify EXPERT]
Signed-off-by: Catalin Marinas <[email protected]>

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

Memory barrier instrumentation is crucial to avoid false positives. To
avoid surprises, run a simple test case in the boot-time

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

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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

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kcsan: Make test follow KUnit style recommendations

Per recently added KUnit style recommendations at
Documentation/dev-tools/kunit/style.rst, make the following changes to
the KCSAN test:

1. Rena

kcsan: Make test follow KUnit style recommendations

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 <[email protected]>
Signed-off-by: Marco Elver <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

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kcsan: Disable branch tracing in core runtime

Disable branch tracing in core KCSAN runtime if branches are being
traced (TRACE_BRANCH_PROFILING). This it to avoid its performance
impact, but also av

kcsan: Disable branch tracing in core runtime

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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

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kcsan: Simplify compiler flags

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 compi

kcsan: Simplify compiler flags

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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

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kcsan: Rename test.c to selftest.c

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

kcsan: Rename test.c to selftest.c

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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

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kcsan: Add test suite

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 o

kcsan: Add test suite

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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

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kcsan, trace: Make KCSAN compatible with tracing

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
instrument

kcsan, trace: Make KCSAN compatible with tracing

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 <[email protected]>
Tested-by: Qian Cai <[email protected]>
Acked-by: Steven Rostedt (VMware) <[email protected]>
Signed-off-by: Marco Elver <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

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kcsan, ubsan: Make KCSAN+UBSAN work together

Context:
http://lkml.kernel.org/r/[email protected]

Reported-by: Randy Dunlap <[email protected]>
Signed-off-by: Ma

kcsan, ubsan: Make KCSAN+UBSAN work together

Context:
http://lkml.kernel.org/r/[email protected]

Reported-by: Randy Dunlap <[email protected]>
Signed-off-by: Marco Elver <[email protected]>
Acked-by: Randy Dunlap <[email protected]> # build-tested
Signed-off-by: Paul E. McKenney <[email protected]>

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kcsan: Add Kernel Concurrency Sanitizer infrastructure

Kernel Concurrency Sanitizer (KCSAN) is a dynamic data-race detector for
kernel space. KCSAN is a sampling watchpoint-based data-race detector.

kcsan: Add Kernel Concurrency Sanitizer infrastructure

Kernel Concurrency Sanitizer (KCSAN) is a dynamic data-race detector for
kernel space. KCSAN is a sampling watchpoint-based data-race detector.
See the included Documentation/dev-tools/kcsan.rst for more details.

This patch adds basic infrastructure, but does not yet enable KCSAN for
any architecture.

Signed-off-by: Marco Elver <[email protected]>
Acked-by: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

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