From: Arnd Bergmann <arnd@arndb.de>
To: Marco Elver <elver@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Dmitry Vyukov <dvyukov@google.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Ingo Molnar <mingo@kernel.org>, Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
clang-built-linux@googlegroups.com
Subject: [PATCH] [v2] ubsan, kcsan: don't combine sanitizer with kcov on clang
Date: Thu, 7 May 2020 18:25:31 +0200 [thread overview]
Message-ID: <20200507162617.2472578-1-arnd@arndb.de> (raw)
In-Reply-To: <CANpmjNPCZ2r9V7t50_yy+F_-roBWJdiQWgmvvcqTFxzdzOwKhg@mail.gmail.com>
Clang does not allow -fsanitize-coverage=trace-{pc,cmp} together
with -fsanitize=bounds or with ubsan:
clang: error: argument unused during compilation: '-fsanitize-coverage=trace-pc' [-Werror,-Wunused-command-line-argument]
clang: error: argument unused during compilation: '-fsanitize-coverage=trace-cmp' [-Werror,-Wunused-command-line-argument]
To avoid the warning, check whether clang can handle this correctly
or disallow ubsan and kcsan when kcov is enabled.
Link: https://bugs.llvm.org/show_bug.cgi?id=45831
Link: https://lore.kernel.org/lkml/20200505142341.1096942-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: this implements Marco's suggestion to check what the compiler
actually supports, and references the bug report I now opened.
Let's wait for replies on that bug report before this gets applied,
in case the feedback there changes the conclusion.
---
lib/Kconfig.kcsan | 11 +++++++++++
lib/Kconfig.ubsan | 11 +++++++++++
2 files changed, 22 insertions(+)
diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan
index ea28245c6c1d..a7276035ca0d 100644
--- a/lib/Kconfig.kcsan
+++ b/lib/Kconfig.kcsan
@@ -3,9 +3,20 @@
config HAVE_ARCH_KCSAN
bool
+config KCSAN_KCOV_BROKEN
+ def_bool KCOV && CC_HAS_SANCOV_TRACE_PC
+ depends on CC_IS_CLANG
+ depends on !$(cc-option,-Werror=unused-command-line-argument -fsanitize=thread -fsanitize-coverage=trace-pc)
+ help
+ Some versions of clang support either KCSAN and KCOV but not the
+ combination of the two.
+ See https://bugs.llvm.org/show_bug.cgi?id=45831 for the status
+ in newer releases.
+
menuconfig KCSAN
bool "KCSAN: dynamic data race detector"
depends on HAVE_ARCH_KCSAN && DEBUG_KERNEL && !KASAN
+ depends on !KCSAN_KCOV_BROKEN
select STACKTRACE
help
The Kernel Concurrency Sanitizer (KCSAN) is a dynamic
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index 929211039bac..a5ba2fd51823 100644
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -26,9 +26,20 @@ config UBSAN_TRAP
the system. For some system builders this is an acceptable
trade-off.
+config UBSAN_KCOV_BROKEN
+ def_bool KCOV && CC_HAS_SANCOV_TRACE_PC
+ depends on CC_IS_CLANG
+ depends on !$(cc-option,-Werror=unused-command-line-argument -fsanitize=bounds -fsanitize-coverage=trace-pc)
+ help
+ Some versions of clang support either UBSAN or KCOV but not the
+ combination of the two.
+ See https://bugs.llvm.org/show_bug.cgi?id=45831 for the status
+ in newer releases.
+
config UBSAN_BOUNDS
bool "Perform array index bounds checking"
default UBSAN
+ depends on !UBSAN_KCOV_BROKEN
help
This option enables detection of directly indexed out of bounds
array accesses, where the array size is known at compile time.
--
2.26.0
next prev parent reply other threads:[~2020-05-07 16:26 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 14:23 [PATCH] ubsan, kcsan: don't combine sanitizer with kcov Arnd Bergmann
2020-05-05 14:36 ` Marco Elver
2020-05-05 14:50 ` Dmitry Vyukov
2020-05-05 14:59 ` Arnd Bergmann
2020-05-05 15:19 ` Marco Elver
2020-05-05 15:28 ` Arnd Bergmann
2020-05-05 17:07 ` Marco Elver
2020-05-07 16:25 ` Arnd Bergmann [this message]
2020-05-07 16:50 ` [PATCH] [v2] ubsan, kcsan: don't combine sanitizer with kcov on clang Marco Elver
2020-05-13 20:02 ` Paul E. McKenney
2020-05-22 16:08 ` [tip: locking/kcsan] ubsan, kcsan: Don't " tip-bot2 for Arnd Bergmann
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