From: Marco Elver <elver@google.com>
To: elver@google.com
Cc: paulmck@kernel.org, dvyukov@google.com, glider@google.com,
andreyknvl@google.com, kasan-dev@googlegroups.com,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
mingo@kernel.org, peterz@infradead.org, will@kernel.org,
clang-built-linux@googlegroups.com
Subject: [PATCH -tip 05/10] kcsan: Remove 'noinline' from __no_kcsan_or_inline
Date: Fri, 15 May 2020 17:03:33 +0200 [thread overview]
Message-ID: <20200515150338.190344-6-elver@google.com> (raw)
In-Reply-To: <20200515150338.190344-1-elver@google.com>
Some compilers incorrectly inline small __no_kcsan functions, which then
results in instrumenting the accesses. For this reason, the 'noinline'
attribute was added to __no_kcsan_or_inline. All known versions of GCC
are affected by this. Supported version of Clang are unaffected, and
never inlines a no_sanitize function.
However, the attribute 'noinline' in __no_kcsan_or_inline causes
unexpected code generation in functions that are __no_kcsan and call a
__no_kcsan_or_inline function.
In certain situations it is expected that the __no_kcsan_or_inline
function is actually inlined by the __no_kcsan function, and *no* calls
are emitted. By removing the 'noinline' attribute we give the compiler
the ability to inline and generate the expected code in __no_kcsan
functions.
Link: https://lkml.kernel.org/r/CANpmjNNOpJk0tprXKB_deiNAv_UmmORf1-2uajLhnLWQQ1hvoA@mail.gmail.com
Signed-off-by: Marco Elver <elver@google.com>
---
include/linux/compiler.h | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index e24cc3a2bc3e..17c98b215572 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -276,11 +276,9 @@ do { \
#ifdef __SANITIZE_THREAD__
/*
* Rely on __SANITIZE_THREAD__ instead of CONFIG_KCSAN, to avoid not inlining in
- * compilation units where instrumentation is disabled. The attribute 'noinline'
- * is required for older compilers, where implicit inlining of very small
- * functions renders __no_sanitize_thread ineffective.
+ * compilation units where instrumentation is disabled.
*/
-# define __no_kcsan_or_inline __no_kcsan noinline notrace __maybe_unused
+# define __no_kcsan_or_inline __no_kcsan notrace __maybe_unused
# define __no_sanitize_or_inline __no_kcsan_or_inline
#else
# define __no_kcsan_or_inline __always_inline
--
2.26.2.761.g0e0b3e54be-goog
next prev parent reply other threads:[~2020-05-15 15:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 15:03 [PATCH -tip 00/10] Fix KCSAN for new ONCE (require Clang 11) Marco Elver
2020-05-15 15:03 ` [PATCH -tip 01/10] ubsan, kcsan: don't combine sanitizer with kcov on clang Marco Elver
2020-05-15 15:03 ` [PATCH -tip 02/10] kcsan: Avoid inserting __tsan_func_entry/exit if possible Marco Elver
2020-05-15 15:03 ` [PATCH -tip 03/10] kcsan: Support distinguishing volatile accesses Marco Elver
2020-05-15 15:03 ` [PATCH -tip 04/10] kcsan: Pass option tsan-instrument-read-before-write to Clang Marco Elver
2020-05-15 15:03 ` Marco Elver [this message]
2020-05-15 15:03 ` [PATCH -tip 06/10] kcsan: Restrict supported compilers Marco Elver
2020-05-15 15:03 ` [PATCH -tip 07/10] kcsan: Update Documentation to change " Marco Elver
2020-05-15 15:03 ` [PATCH -tip 08/10] READ_ONCE, WRITE_ONCE: Remove data_race() wrapping Marco Elver
2020-05-21 9:47 ` Marco Elver
2020-05-21 10:18 ` Marco Elver
2020-05-21 10:22 ` Will Deacon
2020-05-15 15:03 ` [PATCH -tip 09/10] compiler.h: Move function attributes to compiler_types.h Marco Elver
2020-05-15 15:03 ` [PATCH -tip 10/10] compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining Marco Elver
2020-05-21 11:11 ` [PATCH -tip 00/10] Fix KCSAN for new ONCE (require Clang 11) Marco Elver
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