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 --------- v2: * Elaborate comment about instrumentation calls emitted by compilers. * Replace kcsan_check_access(.., {true, false}) with kcsan_check_{read,write} for improved readability. * Introduce __atomic_check_{read,write} in atomic-instrumented.h [Suggested by Mark Rutland]. * Change bug title of race of unknown origin to just say "data-race in". * Refine "Key Properties" in kcsan.rst, and mention observed slow-down. * Add comment about safety of find_watchpoint without user_access_save. * Remove unnecessary preempt_disable/enable and elaborate on comment why we want to disable interrupts and preemptions. * Use common struct kcsan_ctx in task_struct and for per-CPU interrupt contexts [Suggested by Mark Rutland]. * Document x86 build exceptions where no previous above comment explained why we cannot instrument. v1: http://lkml.kernel.org/r/20191016083959.186860-1-elver@xxxxxxxxxx Marco Elver (8): kcsan: Add Kernel Concurrency Sanitizer infrastructure 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/kcsan.rst | 203 ++++++++++ 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 | 147 ++++++++ include/linux/kcsan.h | 108 ++++++ 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 | 14 + kernel/kcsan/atomic.c | 21 ++ kernel/kcsan/core.c | 428 ++++++++++++++++++++++ kernel/kcsan/debugfs.c | 225 ++++++++++++ kernel/kcsan/encoding.h | 94 +++++ kernel/kcsan/kcsan.c | 86 +++++ kernel/kcsan/kcsan.h | 140 +++++++ kernel/kcsan/report.c | 306 ++++++++++++++++ kernel/kcsan/test.c | 117 ++++++ kernel/sched/Makefile | 6 + lib/Kconfig.debug | 2 + lib/Kconfig.kcsan | 88 +++++ 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 | 17 + 46 files changed, 2428 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.c 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.c 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 -- 2.23.0.866.gb869b98d4c-goog
