This is the patch-series for the Kernel Concurrency Sanitizer (KCSAN). KCSAN is a sampling watchpoint-based data-race detector. More details are included in Documentation/dev-tools/kcsan.rst. This patch-series only enables KCSAN for x86, but we expect adding support for other architectures is relatively straightforward (we are aware of experimental ARM64 and POWER support). To gather early feedback, we announced KCSAN back in September, and have integrated the feedback where possible: http://lkml.kernel.org/r/CANpmjNPJ_bHjfLZCAPV23AXFfiPiyXXqqu72n6TgWzb2Gnu1eA@xxxxxxxxxxxxxx We want to point out and acknowledge the work surrounding the LKMM, including several articles that motivate why data-races are dangerous [1, 2], justifying a data-race detector such as KCSAN. [1] https://lwn.net/Articles/793253/ [2] https://lwn.net/Articles/799218/ The current list of known upstream fixes for data-races found by KCSAN can be found here: https://github.com/google/ktsan/wiki/KCSAN#upstream-fixes-of-data-races-found-by-kcsan Changelog --------- v3: * Major changes: - Add microbenchmark. - Add instruction watchpoint skip randomization. - Refactor API and core runtime fast-path and slow-path. Compared to the previous version, with a default config and benchmarked using the added microbenchmark, this version is 3.8x faster. - Make __tsan_unaligned __alias of generic accesses. - Rename kcsan_{begin,end}_atomic -> kcsan_{nestable,flat}_atomic_{begin,end} - For filter list in debugfs.c use kmalloc+krealloc instead of kvmalloc. - Split Documentation into separate patch. v2: http://lkml.kernel.org/r/20191017141305.146193-1-elver@xxxxxxxxxx * Major changes: - Replace kcsan_check_access(.., {true, false}) with kcsan_check_{read,write}. - Change atomic-instrumented.h to use __atomic_check_{read,write}. - Use common struct kcsan_ctx in task_struct and for per-CPU interrupt contexts. v1: http://lkml.kernel.org/r/20191016083959.186860-1-elver@xxxxxxxxxx Marco Elver (9): kcsan: Add Kernel Concurrency Sanitizer infrastructure kcsan: Add Documentation entry in dev-tools objtool, kcsan: Add KCSAN runtime functions to whitelist build, kcsan: Add KCSAN build exceptions seqlock, kcsan: Add annotations for KCSAN seqlock: Require WRITE_ONCE surrounding raw_seqcount_barrier asm-generic, kcsan: Add KCSAN instrumentation for bitops locking/atomics, kcsan: Add KCSAN instrumentation x86, kcsan: Enable KCSAN for x86 Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kcsan.rst | 217 +++++++++ MAINTAINERS | 11 + Makefile | 3 +- arch/x86/Kconfig | 1 + arch/x86/boot/Makefile | 2 + arch/x86/boot/compressed/Makefile | 2 + arch/x86/entry/vdso/Makefile | 3 + arch/x86/include/asm/bitops.h | 6 +- arch/x86/kernel/Makefile | 7 + arch/x86/kernel/cpu/Makefile | 3 + arch/x86/lib/Makefile | 4 + arch/x86/mm/Makefile | 3 + arch/x86/purgatory/Makefile | 2 + arch/x86/realmode/Makefile | 3 + arch/x86/realmode/rm/Makefile | 3 + drivers/firmware/efi/libstub/Makefile | 2 + include/asm-generic/atomic-instrumented.h | 393 +++++++-------- include/asm-generic/bitops-instrumented.h | 18 + include/linux/compiler-clang.h | 9 + include/linux/compiler-gcc.h | 7 + include/linux/compiler.h | 35 +- include/linux/kcsan-checks.h | 97 ++++ include/linux/kcsan.h | 115 +++++ include/linux/sched.h | 4 + include/linux/seqlock.h | 51 +- init/init_task.c | 8 + init/main.c | 2 + kernel/Makefile | 6 + kernel/kcsan/Makefile | 11 + kernel/kcsan/atomic.h | 27 ++ kernel/kcsan/core.c | 560 ++++++++++++++++++++++ kernel/kcsan/debugfs.c | 275 +++++++++++ kernel/kcsan/encoding.h | 94 ++++ kernel/kcsan/kcsan.h | 131 +++++ kernel/kcsan/report.c | 306 ++++++++++++ kernel/kcsan/test.c | 121 +++++ kernel/sched/Makefile | 6 + lib/Kconfig.debug | 2 + lib/Kconfig.kcsan | 119 +++++ lib/Makefile | 3 + mm/Makefile | 8 + scripts/Makefile.kcsan | 6 + scripts/Makefile.lib | 10 + scripts/atomic/gen-atomic-instrumented.sh | 17 +- tools/objtool/check.c | 18 + 46 files changed, 2526 insertions(+), 206 deletions(-) create mode 100644 Documentation/dev-tools/kcsan.rst create mode 100644 include/linux/kcsan-checks.h create mode 100644 include/linux/kcsan.h create mode 100644 kernel/kcsan/Makefile create mode 100644 kernel/kcsan/atomic.h create mode 100644 kernel/kcsan/core.c create mode 100644 kernel/kcsan/debugfs.c create mode 100644 kernel/kcsan/encoding.h create mode 100644 kernel/kcsan/kcsan.h create mode 100644 kernel/kcsan/report.c create mode 100644 kernel/kcsan/test.c create mode 100644 lib/Kconfig.kcsan create mode 100644 scripts/Makefile.kcsan -- 2.24.0.rc1.363.gb1bccd3e3d-goog
