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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 19:03:49 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 19:03:49 +0300 |
commit | f433cf2102fec78cf05ece06fb8e24fbfc6a64d8 (patch) | |
tree | c34ee84aa3a985a32f33211617e4816c046b3560 | |
parent | 5517a2eaec8f525506867988adc6cfe1c414c90a (diff) | |
parent | 144b9152791ffcd038c3b63063999b25780060d8 (diff) | |
download | linux-f433cf2102fec78cf05ece06fb8e24fbfc6a64d8.tar.xz |
Merge tag 'kcsan.2022.12.02a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull KCSAN updates from Paul McKenney:
- Add instrumentation for memcpy(), memset(), and memmove() for Clang
v16+'s new function names that are used when the -fsanitize=thread
argument is given
- Fix objtool warnings from KCSAN's volatile instrumentation, and typos
in a pair of Kconfig options' help clauses
* tag 'kcsan.2022.12.02a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
kcsan: Fix trivial typo in Kconfig help comments
objtool, kcsan: Add volatile read/write instrumentation to whitelist
kcsan: Instrument memcpy/memset/memmove with newer Clang
-rw-r--r-- | kernel/kcsan/core.c | 50 | ||||
-rw-r--r-- | lib/Kconfig.kcsan | 6 | ||||
-rw-r--r-- | tools/objtool/check.c | 10 |
3 files changed, 63 insertions, 3 deletions
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c index fe12dfe254ec..54d077e1a2dc 100644 --- a/kernel/kcsan/core.c +++ b/kernel/kcsan/core.c @@ -14,10 +14,12 @@ #include <linux/init.h> #include <linux/kernel.h> #include <linux/list.h> +#include <linux/minmax.h> #include <linux/moduleparam.h> #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 +1310,51 @@ 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) +{ + /* + * Instead of not setting up watchpoints where accessed size is greater + * than MAX_ENCODABLE_SIZE, truncate checked size to MAX_ENCODABLE_SIZE. + */ + size_t check_len = min_t(size_t, count, MAX_ENCODABLE_SIZE); + + check_access(s, check_len, 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) +{ + size_t check_len = min_t(size_t, len, MAX_ENCODABLE_SIZE); + + check_access(dst, check_len, KCSAN_ACCESS_WRITE, _RET_IP_); + check_access(src, check_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) +{ + size_t check_len = min_t(size_t, len, MAX_ENCODABLE_SIZE); + + check_access(dst, check_len, KCSAN_ACCESS_WRITE, _RET_IP_); + check_access(src, check_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); diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan index 47a693c45864..375575a5a0e3 100644 --- a/lib/Kconfig.kcsan +++ b/lib/Kconfig.kcsan @@ -125,7 +125,7 @@ config KCSAN_SKIP_WATCH default 4000 help The number of per-CPU memory operations to skip, before another - watchpoint is set up, i.e. one in KCSAN_WATCH_SKIP per-CPU + watchpoint is set up, i.e. one in KCSAN_SKIP_WATCH per-CPU memory operations are used to set up a watchpoint. A smaller value results in more aggressive race detection, whereas a larger value improves system performance at the cost of missing some races. @@ -135,8 +135,8 @@ config KCSAN_SKIP_WATCH_RANDOMIZE default y help If instruction skip count should be randomized, where the maximum is - KCSAN_WATCH_SKIP. If false, the chosen value is always - KCSAN_WATCH_SKIP. + KCSAN_SKIP_WATCH. If false, the chosen value is always + KCSAN_SKIP_WATCH. config KCSAN_INTERRUPT_WATCHER bool "Interruptible watchers" if !KCSAN_STRICT diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 43ec14c29a60..a7f1e6c8bb0a 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -999,6 +999,16 @@ static const char *uaccess_safe_builtin[] = { "__tsan_read_write4", "__tsan_read_write8", "__tsan_read_write16", + "__tsan_volatile_read1", + "__tsan_volatile_read2", + "__tsan_volatile_read4", + "__tsan_volatile_read8", + "__tsan_volatile_read16", + "__tsan_volatile_write1", + "__tsan_volatile_write2", + "__tsan_volatile_write4", + "__tsan_volatile_write8", + "__tsan_volatile_write16", "__tsan_atomic8_load", "__tsan_atomic16_load", "__tsan_atomic32_load", |