Re: [PATCH v3 0/9] Add Kernel Concurrency Sanitizer (KCSAN)
From: Marco Elver
Date: Mon Nov 04 2019 - 13:41:47 EST
On Mon, 4 Nov 2019 at 17:47, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
>
> On Mon, Nov 04, 2019 at 03:27:36PM +0100, Marco Elver wrote:
> > 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
>
> Making this more accessible to more people seems like a good thing.
> So, for the series:
>
> Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Much appreciated. Thanks, Paul!
Any suggestions which tree this could eventually land in?
Thanks,
-- Marco
> > 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
> >
>
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