+ kmsan-compiler_types-declare-__no_sanitize_or_inline.patch added to mm-hotfixes-unstable branch

+ kmsan-compiler_types-declare-__no_sanitize_or_inline.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

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

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Alexander Potapenko <glider@google.com>
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@google.com
Fixes: 5de0ce85f5a4 ("kmsan: mark noinstr as __no_sanitize_memory")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: syzbot+355c5bb8c1445c871ee8@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/000000000000826ac1061675b0e3@google.com
Cc: <stable@vger.kernel.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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@google.com are

kmsan-compiler_types-declare-__no_sanitize_or_inline.patch

+ kmsan-compiler_types-declare-__no_sanitize_or_inline.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

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

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Alexander Potapenko <glider@google.com>
Subject: kmsan: compiler_types: declare __no_sanitize_or_inline
Date: Thu, 25 Apr 2024 11:28:59 +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 inline the annotated function.

Link: https://lkml.kernel.org/r/20240425092859.3370297-1-glider@google.com
Reported-by: syzbot+355c5bb8c1445c871ee8@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/000000000000826ac1061675b0e3@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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@google.com are

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