* [PATCH v2 2/3] kcsan: Instrument memcpy/memset/memmove with newer Clang [not found] <20220909073840.45349-1-elver@google.com> @ 2022-09-09 7:38 ` Marco Elver 2022-09-09 8:38 ` Dmitry Vyukov 0 siblings, 1 reply; 3+ messages in thread From: Marco Elver @ 2022-09-09 7:38 UTC (permalink / raw) To: elver, Paul E. McKenney Cc: Mark Rutland, Dmitry Vyukov, Alexander Potapenko, Boqun Feng, kasan-dev, linux-kernel, Nathan Chancellor, Nick Desaulniers, llvm, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Christian Borntraeger, Sven Schnelle, Peter Zijlstra, linux-s390, stable With Clang version 16+, -fsanitize=thread will turn memcpy/memset/memmove calls in instrumented functions into __tsan_memcpy/__tsan_memset/__tsan_memmove calls respectively. Add these functions to the core KCSAN runtime, so that we (a) catch data races with mem* functions, and (b) won't run into linker errors with such newer compilers. Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Marco Elver <elver@google.com> --- v2: * Fix for architectures which do not provide their own memcpy/memset/memmove and instead use the generic versions in lib/string. In this case we'll just alias the __tsan_ variants. --- kernel/kcsan/core.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c index fe12dfe254ec..4015f2a3e7f6 100644 --- a/kernel/kcsan/core.c +++ b/kernel/kcsan/core.c @@ -18,6 +18,7 @@ #include <linux/percpu.h> #include <linux/preempt.h> #include <linux/sched.h> +#include <linux/string.h> #include <linux/uaccess.h> #include "encoding.h" @@ -1308,3 +1309,41 @@ noinline void __tsan_atomic_signal_fence(int memorder) } } EXPORT_SYMBOL(__tsan_atomic_signal_fence); + +#ifdef __HAVE_ARCH_MEMSET +void *__tsan_memset(void *s, int c, size_t count); +noinline void *__tsan_memset(void *s, int c, size_t count) +{ + check_access(s, count, KCSAN_ACCESS_WRITE, _RET_IP_); + return __memset(s, c, count); +} +#else +void *__tsan_memset(void *s, int c, size_t count) __alias(memset); +#endif +EXPORT_SYMBOL(__tsan_memset); + +#ifdef __HAVE_ARCH_MEMMOVE +void *__tsan_memmove(void *dst, const void *src, size_t len); +noinline void *__tsan_memmove(void *dst, const void *src, size_t len) +{ + check_access(dst, len, KCSAN_ACCESS_WRITE, _RET_IP_); + check_access(src, len, 0, _RET_IP_); + return __memmove(dst, src, len); +} +#else +void *__tsan_memmove(void *dst, const void *src, size_t len) __alias(memmove); +#endif +EXPORT_SYMBOL(__tsan_memmove); + +#ifdef __HAVE_ARCH_MEMCPY +void *__tsan_memcpy(void *dst, const void *src, size_t len); +noinline void *__tsan_memcpy(void *dst, const void *src, size_t len) +{ + check_access(dst, len, KCSAN_ACCESS_WRITE, _RET_IP_); + check_access(src, len, 0, _RET_IP_); + return __memcpy(dst, src, len); +} +#else +void *__tsan_memcpy(void *dst, const void *src, size_t len) __alias(memcpy); +#endif +EXPORT_SYMBOL(__tsan_memcpy); -- 2.37.2.789.g6183377224-goog ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2 2/3] kcsan: Instrument memcpy/memset/memmove with newer Clang 2022-09-09 7:38 ` [PATCH v2 2/3] kcsan: Instrument memcpy/memset/memmove with newer Clang Marco Elver @ 2022-09-09 8:38 ` Dmitry Vyukov 2022-09-09 8:43 ` Marco Elver 0 siblings, 1 reply; 3+ messages in thread From: Dmitry Vyukov @ 2022-09-09 8:38 UTC (permalink / raw) To: Marco Elver Cc: Paul E. McKenney, Mark Rutland, Alexander Potapenko, Boqun Feng, kasan-dev, linux-kernel, Nathan Chancellor, Nick Desaulniers, llvm, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Christian Borntraeger, Sven Schnelle, Peter Zijlstra, linux-s390, stable On Fri, 9 Sept 2022 at 09:38, Marco Elver <elver@google.com> wrote: > > With Clang version 16+, -fsanitize=thread will turn > memcpy/memset/memmove calls in instrumented functions into > __tsan_memcpy/__tsan_memset/__tsan_memmove calls respectively. > > Add these functions to the core KCSAN runtime, so that we (a) catch data > races with mem* functions, and (b) won't run into linker errors with > such newer compilers. > > Cc: stable@vger.kernel.org # v5.10+ > Signed-off-by: Marco Elver <elver@google.com> > --- > v2: > * Fix for architectures which do not provide their own > memcpy/memset/memmove and instead use the generic versions in > lib/string. In this case we'll just alias the __tsan_ variants. > --- > kernel/kcsan/core.c | 39 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c > index fe12dfe254ec..4015f2a3e7f6 100644 > --- a/kernel/kcsan/core.c > +++ b/kernel/kcsan/core.c > @@ -18,6 +18,7 @@ > #include <linux/percpu.h> > #include <linux/preempt.h> > #include <linux/sched.h> > +#include <linux/string.h> > #include <linux/uaccess.h> > > #include "encoding.h" > @@ -1308,3 +1309,41 @@ noinline void __tsan_atomic_signal_fence(int memorder) > } > } > EXPORT_SYMBOL(__tsan_atomic_signal_fence); > + > +#ifdef __HAVE_ARCH_MEMSET > +void *__tsan_memset(void *s, int c, size_t count); > +noinline void *__tsan_memset(void *s, int c, size_t count) > +{ > + check_access(s, count, KCSAN_ACCESS_WRITE, _RET_IP_); These can use large sizes, does it make sense to truncate it to MAX_ENCODABLE_SIZE? > + return __memset(s, c, count); > +} > +#else > +void *__tsan_memset(void *s, int c, size_t count) __alias(memset); > +#endif > +EXPORT_SYMBOL(__tsan_memset); > + > +#ifdef __HAVE_ARCH_MEMMOVE > +void *__tsan_memmove(void *dst, const void *src, size_t len); > +noinline void *__tsan_memmove(void *dst, const void *src, size_t len) > +{ > + check_access(dst, len, KCSAN_ACCESS_WRITE, _RET_IP_); > + check_access(src, len, 0, _RET_IP_); > + return __memmove(dst, src, len); > +} > +#else > +void *__tsan_memmove(void *dst, const void *src, size_t len) __alias(memmove); > +#endif > +EXPORT_SYMBOL(__tsan_memmove); > + > +#ifdef __HAVE_ARCH_MEMCPY > +void *__tsan_memcpy(void *dst, const void *src, size_t len); > +noinline void *__tsan_memcpy(void *dst, const void *src, size_t len) > +{ > + check_access(dst, len, KCSAN_ACCESS_WRITE, _RET_IP_); > + check_access(src, len, 0, _RET_IP_); > + return __memcpy(dst, src, len); > +} > +#else > +void *__tsan_memcpy(void *dst, const void *src, size_t len) __alias(memcpy); > +#endif > +EXPORT_SYMBOL(__tsan_memcpy); > -- > 2.37.2.789.g6183377224-goog > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2 2/3] kcsan: Instrument memcpy/memset/memmove with newer Clang 2022-09-09 8:38 ` Dmitry Vyukov @ 2022-09-09 8:43 ` Marco Elver 0 siblings, 0 replies; 3+ messages in thread From: Marco Elver @ 2022-09-09 8:43 UTC (permalink / raw) To: Dmitry Vyukov Cc: Paul E. McKenney, Mark Rutland, Alexander Potapenko, Boqun Feng, kasan-dev, linux-kernel, Nathan Chancellor, Nick Desaulniers, llvm, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Christian Borntraeger, Sven Schnelle, Peter Zijlstra, linux-s390, stable On Fri, 9 Sept 2022 at 10:38, Dmitry Vyukov <dvyukov@google.com> wrote: > > On Fri, 9 Sept 2022 at 09:38, Marco Elver <elver@google.com> wrote: > > > > With Clang version 16+, -fsanitize=thread will turn > > memcpy/memset/memmove calls in instrumented functions into > > __tsan_memcpy/__tsan_memset/__tsan_memmove calls respectively. > > > > Add these functions to the core KCSAN runtime, so that we (a) catch data > > races with mem* functions, and (b) won't run into linker errors with > > such newer compilers. > > > > Cc: stable@vger.kernel.org # v5.10+ > > Signed-off-by: Marco Elver <elver@google.com> > > --- > > v2: > > * Fix for architectures which do not provide their own > > memcpy/memset/memmove and instead use the generic versions in > > lib/string. In this case we'll just alias the __tsan_ variants. > > --- > > kernel/kcsan/core.c | 39 +++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 39 insertions(+) > > > > diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c > > index fe12dfe254ec..4015f2a3e7f6 100644 > > --- a/kernel/kcsan/core.c > > +++ b/kernel/kcsan/core.c > > @@ -18,6 +18,7 @@ > > #include <linux/percpu.h> > > #include <linux/preempt.h> > > #include <linux/sched.h> > > +#include <linux/string.h> > > #include <linux/uaccess.h> > > > > #include "encoding.h" > > @@ -1308,3 +1309,41 @@ noinline void __tsan_atomic_signal_fence(int memorder) > > } > > } > > EXPORT_SYMBOL(__tsan_atomic_signal_fence); > > + > > +#ifdef __HAVE_ARCH_MEMSET > > +void *__tsan_memset(void *s, int c, size_t count); > > +noinline void *__tsan_memset(void *s, int c, size_t count) > > +{ > > + check_access(s, count, KCSAN_ACCESS_WRITE, _RET_IP_); > > These can use large sizes, does it make sense to truncate it to > MAX_ENCODABLE_SIZE? Hmm, good point - that way it can still set up watchpoints on them. I'll do a v3. ^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-09-09 7:38 ` [PATCH v2 2/3] kcsan: Instrument memcpy/memset/memmove with newer Clang Marco Elver
2022-09-09 8:38 ` Dmitry Vyukov
2022-09-09 8:43 ` Marco Elver
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