projects/linux·commit f433cf21

Merge tag 'kcsan.2022.12.02a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

f433cf21 · Linus Torvalds <[email protected]> · 2022-12-12 08:03:49 -08:00

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
Commit
f433cf2102fec78cf05ece06fb8e24fbfc6a64d8
Parents
5517a2ea · 144b9152

Merge commit. Changes below are compared with the first parent: 5517a2ea.

Changes

3 files changed · +63 −3

FileStatusAddDelContent
kernel/kcsan/core.cmodified+50−0View file
lib/Kconfig.kcsanmodified+3−3View file
tools/objtool/check.cmodified+10−0View file

kernel/kcsan/core.c

View file
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
index fe12dfe..54d077e 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);

lib/Kconfig.kcsan

View file
diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan
index 47a693c..375575a 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

tools/objtool/check.c

View file
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 43ec14c..a7f1e6c 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",