Merge branch 'kcsan' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into locking/core

Pull KCSAN updates for v5.10 from Paul E. McKenney:

 - Improve kernel messages.

 - Be more permissive with bitops races under KCSAN_ASSUME_PLAIN_WRITES_ATOMIC=y.

 - Optimize debugfs stat counters.

 - Introduce the instrument_*read_write() annotations, to provide a
   finer description of certain ops - using KCSAN's compound instrumentation.
   Use them for atomic RNW and bitops, where appropriate.
   Doing this might find new races.
   (Depends on the compiler having tsan-compound-read-before-write=1 support.)

 - Support atomic built-ins, which will help certain architectures, such as s390.

 - Misc enhancements and smaller fixes.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h
index 43e6ea591975..42faebbaa202 100644
--- a/include/linux/instrumented.h
+++ b/include/linux/instrumented.h
@@ -43,6 +43,21 @@ static __always_inline void instrument_write(const volatile void *v, size_t size
 }
 
 /**
+ * instrument_read_write - instrument regular read-write access
+ *
+ * Instrument a regular write access. The instrumentation should be inserted
+ * before the actual write happens.
+ *
+ * @ptr address of access
+ * @size size of access
+ */
+static __always_inline void instrument_read_write(const volatile void *v, size_t size)
+{
+	kasan_check_write(v, size);
+	kcsan_check_read_write(v, size);
+}
+
+/**
  * instrument_atomic_read - instrument atomic read access
  *
  * Instrument an atomic read access. The instrumentation should be inserted
@@ -73,6 +88,21 @@ static __always_inline void instrument_atomic_write(const volatile void *v, size
 }
 
 /**
+ * instrument_atomic_read_write - instrument atomic read-write access
+ *
+ * Instrument an atomic read-write access. The instrumentation should be
+ * inserted before the actual write happens.
+ *
+ * @ptr address of access
+ * @size size of access
+ */
+static __always_inline void instrument_atomic_read_write(const volatile void *v, size_t size)
+{
+	kasan_check_write(v, size);
+	kcsan_check_atomic_read_write(v, size);
+}
+
+/**
  * instrument_copy_to_user - instrument reads of copy_to_user
  *
  * Instrument reads from kernel memory, that are due to copy_to_user (and