The patch titled
Subject: kmsan: compiler_types: declare __no_sanitize_or_inline
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
kmsan-compiler_types-declare-__no_sanitize_or_inline.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kmsan-compiler_types-declare-__no_sanitize_or_inline.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Alexander Potapenko <glider@xxxxxxxxxx>
Subject: kmsan: compiler_types: declare __no_sanitize_or_inline
Date: Fri, 26 Apr 2024 11:16:22 +0200
It turned out that KMSAN instruments READ_ONCE_NOCHECK(), resulting in
false positive reports, because __no_sanitize_or_inline enforced inlining.
Properly declare __no_sanitize_or_inline under __SANITIZE_MEMORY__, so
that it does not __always_inline the annotated function.
Link: https://lkml.kernel.org/r/20240426091622.3846771-1-glider@xxxxxxxxxx
Fixes: 5de0ce85f5a4 ("kmsan: mark noinstr as __no_sanitize_memory")
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Reported-by: syzbot+355c5bb8c1445c871ee8@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/000000000000826ac1061675b0e3@xxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Miguel Ojeda <ojeda@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/compiler_types.h | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/include/linux/compiler_types.h~kmsan-compiler_types-declare-__no_sanitize_or_inline
+++ a/include/linux/compiler_types.h
@@ -278,6 +278,17 @@ struct ftrace_likely_data {
# define __no_kcsan
#endif
+#ifdef __SANITIZE_MEMORY__
+/*
+ * Similarly to KASAN and KCSAN, KMSAN loses function attributes of inlined
+ * functions, therefore disabling KMSAN checks also requires disabling inlining.
+ *
+ * __no_sanitize_or_inline effectively prevents KMSAN from reporting errors
+ * within the function and marks all its outputs as initialized.
+ */
+# define __no_sanitize_or_inline __no_kmsan_checks notrace __maybe_unused
+#endif
+
#ifndef __no_sanitize_or_inline
#define __no_sanitize_or_inline __always_inline
#endif
_
Patches currently in -mm which might be from glider@xxxxxxxxxx are
kmsan-compiler_types-declare-__no_sanitize_or_inline.patch
