+ instrumentedh-add-instrument_memcpy_before-instrument_memcpy_after.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: instrumented.h: add instrument_memcpy_before, instrument_memcpy_after
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     instrumentedh-add-instrument_memcpy_before-instrument_memcpy_after.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/instrumentedh-add-instrument_memcpy_before-instrument_memcpy_after.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Alexander Potapenko <glider@google.com>
Subject: instrumented.h: add instrument_memcpy_before, instrument_memcpy_after
Date: Wed, 20 Mar 2024 11:18:50 +0100

Bug detection tools based on compiler instrumentation may miss memory
accesses in custom memcpy implementations (such as copy_mc_to_kernel). 
Provide instrumentation hooks that tell KASAN, KCSAN, and KMSAN about such
accesses.

Link: https://lore.kernel.org/all/3b7dbd88-0861-4638-b2d2-911c97a4cadf@I-love.SAKURA.ne.jp/
Link: https://lkml.kernel.org/r/20240320101851.2589698-2-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/instrumented.h |   35 +++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

--- a/include/linux/instrumented.h~instrumentedh-add-instrument_memcpy_before-instrument_memcpy_after
+++ a/include/linux/instrumented.h
@@ -148,6 +148,41 @@ instrument_copy_from_user_after(const vo
 }
 
 /**
+ * instrument_memcpy_before - add instrumentation before non-instrumented memcpy
+ * @to: destination address
+ * @from: source address
+ * @n: number of bytes to copy
+ *
+ * Instrument memory accesses that happen in custom memcpy implementations. The
+ * instrumentation should be inserted before the memcpy call.
+ */
+static __always_inline void instrument_memcpy_before(void *to, const void *from,
+						     unsigned long n)
+{
+	kasan_check_write(to, n);
+	kasan_check_read(from, n);
+	kcsan_check_write(to, n);
+	kcsan_check_read(from, n);
+}
+
+/**
+ * instrument_memcpy_after - add instrumentation after non-instrumented memcpy
+ * @to: destination address
+ * @from: source address
+ * @n: number of bytes to copy
+ * @left: number of bytes not copied (if known)
+ *
+ * Instrument memory accesses that happen in custom memcpy implementations. The
+ * instrumentation should be inserted after the memcpy call.
+ */
+static __always_inline void instrument_memcpy_after(void *to, const void *from,
+						    unsigned long n,
+						    unsigned long left)
+{
+	kmsan_memmove(to, from, n - left);
+}
+
+/**
  * instrument_get_user() - add instrumentation to get_user()-like macros
  * @to: destination variable, may not be address-taken
  *
_

Patches currently in -mm which might be from glider@google.com are

mm-kmsan-implement-kmsan_memmove.patch
instrumentedh-add-instrument_memcpy_before-instrument_memcpy_after.patch
x86-call-instrumentation-hooks-from-copy_mcc.patch